Index: /branches/rel_ag_9_4_0_493_SBOM/restfulapi/proxy/media/node_modules/grunt/node_modules/grunt-legacy-log/node_modules/lodash/README.md
===================================================================
--- /branches/rel_ag_9_4_0_493_SBOM/restfulapi/proxy/media/node_modules/grunt/node_modules/grunt-legacy-log/node_modules/lodash/README.md	(revision 20239)
+++ /branches/rel_ag_9_4_0_493_SBOM/restfulapi/proxy/media/node_modules/grunt/node_modules/grunt-legacy-log/node_modules/lodash/README.md	(working copy)
@@ -1,145 +1,39 @@
-# Lo-Dash v2.4.2
-A utility library delivering consistency, [customization](https://lodash.com/custom-builds), [performance](https://lodash.com/benchmarks), & [extras](https://lodash.com/#features).
+# lodash v4.17.21
 
-## Download
+The [Lodash](https://lodash.com/) library exported as [Node.js](https://nodejs.org/) modules.
 
-Check out our [wiki]([https://github.com/lodash/lodash/wiki/build-differences]) for details over the differences between builds.
+## Installation
 
-* Modern builds perfect for newer browsers/environments:<br>
-[Development](https://raw.github.com/lodash/lodash/2.4.2/dist/lodash.js) &
-[Production](https://raw.github.com/lodash/lodash/2.4.2/dist/lodash.min.js)
-
-* Compatibility builds for older environment support too:<br>
-[Development](https://raw.github.com/lodash/lodash/2.4.2/dist/lodash.compat.js) &
-[Production](https://raw.github.com/lodash/lodash/2.4.2/dist/lodash.compat.min.js)
-
-* Underscore builds to use as a drop-in replacement:<br>
-[Development](https://raw.github.com/lodash/lodash/2.4.2/dist/lodash.underscore.js) &
-[Production](https://raw.github.com/lodash/lodash/2.4.2/dist/lodash.underscore.min.js)
-
-CDN copies are available on [cdnjs](http://cdnjs.com/libraries/lodash.js/) & [jsDelivr](http://www.jsdelivr.com/#!lodash). For smaller file sizes, create [custom builds](https://lodash.com/custom-builds) with only the features needed.
-
-Love modules? We’ve got you covered with [lodash-amd](https://npmjs.org/package/lodash-amd), [lodash-es6](https://github.com/lodash/lodash-es6), [lodash-node](https://npmjs.org/package/lodash-node), & [npm packages](https://npmjs.org/browse/keyword/lodash-modularized) per method.
-
-## Dive in
-
-There’s plenty of **[documentation](https://lodash.com/docs)**, [unit tests](https://lodash.com/tests), & [benchmarks](https://lodash.com/benchmarks).<br>
-Check out <a href="http://devdocs.io/lodash/">DevDocs</a> as a fast, organized, & searchable interface for our documentation.
-
-The full changelog for this release is available on our [wiki](https://github.com/lodash/lodash/wiki/Changelog).<br>
-A list of upcoming features is available on our [roadmap](https://github.com/lodash/lodash/wiki/Roadmap).
-
-## Installation & usage
-
-In browsers:
-
-```html
-<script src="lodash.js"></script>
+Using npm:
+```shell
+$ npm i -g npm
+$ npm i --save lodash
 ```
 
-Using [`npm`](http://npmjs.org/):
-
-```bash
-npm i --save lodash
-
-{sudo} npm i -g lodash
-npm ln lodash
-```
-
-In [Node.js](http://nodejs.org/) & [Ringo](http://ringojs.org/):
-
+In Node.js:
 ```js
+// Load the full build.
 var _ = require('lodash');
-// or as Underscore
-var _ = require('lodash/dist/lodash.underscore');
-```
-
-**Notes:**
- * Don’t assign values to [special variable](http://nodejs.org/api/repl.html#repl_repl_features) `_` when in the REPL
- * If Lo-Dash is installed globally, run [`npm ln lodash`](http://blog.nodejs.org/2011/03/23/npm-1-0-global-vs-local-installation/) in your project’s root directory *before* requiring it
-
-In [Rhino](http://www.mozilla.org/rhino/):
-
-```js
-load('lodash.js');
-```
-
-In an AMD loader:
-
-```js
-require({
-  'packages': [
-    { 'name': 'lodash', 'location': 'path/to/lodash', 'main': 'lodash' }
-  ]
-},
-['lodash'], function(_) {
-  console.log(_.VERSION);
-});
+// Load the core build.
+var _ = require('lodash/core');
+// Load the FP build for immutable auto-curried iteratee-first data-last methods.
+var fp = require('lodash/fp');
+
+// Load method categories.
+var array = require('lodash/array');
+var object = require('lodash/fp/object');
+
+// Cherry-pick methods for smaller browserify/rollup/webpack bundles.
+var at = require('lodash/at');
+var curryN = require('lodash/fp/curryN');
 ```
 
-## Resources
-
- * Podcasts
-  - [JavaScript Jabber](http://javascriptjabber.com/079-jsj-lo-dash-with-john-david-dalton/)
+See the [package source](https://github.com/lodash/lodash/tree/4.17.21-npm) for more details.
 
- * Posts
-  - [Say “Hello” to Lo-Dash](http://kitcambridge.be/blog/say-hello-to-lo-dash/)
-  - [Custom builds in Lo-Dash 2.0](http://kitcambridge.be/blog/custom-builds-in-lo-dash-2-dot-0/)
-
- * Videos
-  - [Introduction](https://vimeo.com/44154599)
-  - [Origins](https://vimeo.com/44154600)
-  - [Optimizations & builds](https://vimeo.com/44154601)
-  - [Native method use](https://vimeo.com/48576012)
-  - [Testing](https://vimeo.com/45865290)
-  - [CascadiaJS ’12](http://www.youtube.com/watch?v=dpPy4f_SeEk)
-
- A list of other community created podcasts, posts, & videos is available on our [wiki](https://github.com/lodash/lodash/wiki/Resources).
-
-## Features
-
- * AMD loader support ([curl](https://github.com/cujojs/curl), [dojo](http://dojotoolkit.org/), [requirejs](http://requirejs.org/), etc.)
- * [_(…)](https://lodash.com/docs#_) supports intuitive chaining
- * [_.at](https://lodash.com/docs#at) for cherry-picking collection values
- * [_.bindKey](https://lodash.com/docs#bindKey) for binding [*“lazy”*](http://michaux.ca/articles/lazy-function-definition-pattern) defined methods
- * [_.clone](https://lodash.com/docs#clone) supports shallow cloning of `Date` & `RegExp` objects
- * [_.cloneDeep](https://lodash.com/docs#cloneDeep) for deep cloning arrays & objects
- * [_.constant](https://lodash.com/docs#constant) & [_.property](https://lodash.com/docs#property) function generators for composing functions
- * [_.contains](https://lodash.com/docs#contains) accepts a `fromIndex`
- * [_.create](https://lodash.com/docs#create) for easier object inheritance
- * [_.createCallback](https://lodash.com/docs#createCallback) for extending callbacks in methods & mixins
- * [_.curry](https://lodash.com/docs#curry) for creating [curried](http://hughfdjackson.com/javascript/2013/07/06/why-curry-helps/) functions
- * [_.debounce](https://lodash.com/docs#debounce) & [_.throttle](https://lodash.com/docs#throttle) accept additional `options` for more control
- * [_.findIndex](https://lodash.com/docs#findIndex) & [_.findKey](https://lodash.com/docs#findKey) for finding indexes & keys
- * [_.forEach](https://lodash.com/docs#forEach) is chainable & supports exiting early
- * [_.forIn](https://lodash.com/docs#forIn) for iterating own & inherited properties
- * [_.forOwn](https://lodash.com/docs#forOwn) for iterating own properties
- * [_.isPlainObject](https://lodash.com/docs#isPlainObject) for checking if values are created by `Object`
- * [_.mapValues](https://lodash.com/docs#mapValues) for [mapping](https://lodash.com/docs#map) values to an object
- * [_.memoize](https://lodash.com/docs#memoize) exposes the `cache` of memoized functions
- * [_.merge](https://lodash.com/docs#merge) for a deep [_.extend](https://lodash.com/docs#extend)
- * [_.noop](https://lodash.com/docs#noop) for function placeholders
- * [_.now](https://lodash.com/docs#now) as a cross-browser `Date.now` alternative
- * [_.parseInt](https://lodash.com/docs#parseInt) for consistent behavior
- * [_.pull](https://lodash.com/docs#pull) & [_.remove](https://lodash.com/docs#remove) for mutating arrays
- * [_.random](https://lodash.com/docs#random) supports returning floating-point numbers
- * [_.runInContext](https://lodash.com/docs#runInContext) for easier mocking
- * [_.sortBy](https://lodash.com/docs#sortBy) supports sorting by multiple properties
- * [_.support](https://lodash.com/docs#support) for flagging environment features
- * [_.template](https://lodash.com/docs#template) supports [*“imports”*](https://lodash.com/docs#templateSettings_imports) options & [ES6 template delimiters](http://people.mozilla.org/~jorendorff/es6-draft.html#sec-literals-string-literals)
- * [_.transform](https://lodash.com/docs#transform) as a powerful alternative to [_.reduce](https://lodash.com/docs#reduce) for transforming objects
- * [_.where](https://lodash.com/docs#where) supports deep object comparisons
- * [_.xor](https://lodash.com/docs#xor) as a companion to [_.difference](https://lodash.com/docs#difference), [_.intersection](https://lodash.com/docs#intersection), & [_.union](https://lodash.com/docs#union)
- * [_.zip](https://lodash.com/docs#zip) is capable of unzipping values
- * [_.omit](https://lodash.com/docs#omit), [_.pick](https://lodash.com/docs#pick), &
-   [more](https://lodash.com/docs "_.assign, _.clone, _.cloneDeep, _.first, _.initial, _.isEqual, _.last, _.merge, _.rest") accept callbacks
- * [_.contains](https://lodash.com/docs#contains), [_.toArray](https://lodash.com/docs#toArray), &
-   [more](https://lodash.com/docs "_.at, _.countBy, _.every, _.filter, _.find, _.forEach, _.forEachRight, _.groupBy, _.invoke, _.map, _.max, _.min, _.pluck, _.reduce, _.reduceRight, _.reject, _.shuffle, _.size, _.some, _.sortBy, _.where") accept strings
- * [_.filter](https://lodash.com/docs#filter), [_.map](https://lodash.com/docs#map), &
-   [more](https://lodash.com/docs "_.countBy, _.every, _.find, _.findKey, _.findLast, _.findLastIndex, _.findLastKey, _.first, _.groupBy, _.initial, _.last, _.max, _.min, _.reject, _.rest, _.some, _.sortBy, _.sortedIndex, _.uniq") support *“_.pluck”* & *“_.where”* shorthands
- * [_.findLast](https://lodash.com/docs#findLast), [_.findLastIndex](https://lodash.com/docs#findLastIndex), &
-   [more](https://lodash.com/docs "_.findLastKey, _.forEachRight, _.forInRight, _.forOwnRight, _.partialRight") right-associative methods
+**Note:**<br>
+Install [n_](https://www.npmjs.com/package/n_) for Lodash use in the Node.js < 6 REPL.
 
 ## Support
 
-Tested in Chrome 5~31, Firefox 2~25, IE 6-11, Opera 9.25-17, Safari 3-7, Node.js 0.6.21-0.10.22, Narwhal 0.3.2, PhantomJS 1.9.2, RingoJS 0.9, & Rhino 1.7RC5.
+Tested in Chrome 74-75, Firefox 66-67, IE 11, Edge 18, Safari 11-12, & Node.js 8-12.<br>
+Automated [browser](https://saucelabs.com/u/lodash) & [CI](https://travis-ci.org/lodash/lodash/) test runs are available.
Index: /branches/rel_ag_9_4_0_493_SBOM/restfulapi/proxy/media/node_modules/grunt/node_modules/grunt-legacy-log/node_modules/lodash/lodash.js
===================================================================
--- /branches/rel_ag_9_4_0_493_SBOM/restfulapi/proxy/media/node_modules/grunt/node_modules/grunt-legacy-log/node_modules/lodash/lodash.js	(revision 20239)
+++ /branches/rel_ag_9_4_0_493_SBOM/restfulapi/proxy/media/node_modules/grunt/node_modules/grunt-legacy-log/node_modules/lodash/lodash.js	(working copy)
@@ -1,642 +1,1685 @@
 /**
  * @license
- * Lo-Dash 2.4.2 <https://lodash.com/>
- * Copyright 2012-2013 The Dojo Foundation <http://dojofoundation.org/>
- * Based on Underscore.js 1.5.2 <http://underscorejs.org/LICENSE>
- * Copyright 2009-2013 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
- * Available under MIT license <https://lodash.com/license>
+ * Lodash <https://lodash.com/>
+ * Copyright OpenJS Foundation and other contributors <https://openjsf.org/>
+ * Released under MIT license <https://lodash.com/license>
+ * Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
+ * Copyright Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
  */
 ;(function() {
 
-  /** Used as a safe reference for `undefined` in pre ES5 environments */
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
   var undefined;
 
-  /** Used to pool arrays and objects used internally */
-  var arrayPool = [],
-      objectPool = [];
+  /** Used as the semantic version number. */
+  var VERSION = '4.17.21';
 
-  /** Used to generate unique IDs */
-  var idCounter = 0;
+  /** Used as the size to enable large array optimizations. */
+  var LARGE_ARRAY_SIZE = 200;
 
-  /** Used internally to indicate various things */
-  var indicatorObject = {};
+  /** Error message constants. */
+  var CORE_ERROR_TEXT = 'Unsupported core-js use. Try https://npms.io/search?q=ponyfill.',
+      FUNC_ERROR_TEXT = 'Expected a function',
+      INVALID_TEMPL_VAR_ERROR_TEXT = 'Invalid `variable` option passed into `_.template`';
+
+  /** Used to stand-in for `undefined` hash values. */
+  var HASH_UNDEFINED = '__lodash_hash_undefined__';
+
+  /** Used as the maximum memoize cache size. */
+  var MAX_MEMOIZE_SIZE = 500;
+
+  /** Used as the internal argument placeholder. */
+  var PLACEHOLDER = '__lodash_placeholder__';
+
+  /** Used to compose bitmasks for cloning. */
+  var CLONE_DEEP_FLAG = 1,
+      CLONE_FLAT_FLAG = 2,
+      CLONE_SYMBOLS_FLAG = 4;
+
+  /** Used to compose bitmasks for value comparisons. */
+  var COMPARE_PARTIAL_FLAG = 1,
+      COMPARE_UNORDERED_FLAG = 2;
+
+  /** Used to compose bitmasks for function metadata. */
+  var WRAP_BIND_FLAG = 1,
+      WRAP_BIND_KEY_FLAG = 2,
+      WRAP_CURRY_BOUND_FLAG = 4,
+      WRAP_CURRY_FLAG = 8,
+      WRAP_CURRY_RIGHT_FLAG = 16,
+      WRAP_PARTIAL_FLAG = 32,
+      WRAP_PARTIAL_RIGHT_FLAG = 64,
+      WRAP_ARY_FLAG = 128,
+      WRAP_REARG_FLAG = 256,
+      WRAP_FLIP_FLAG = 512;
+
+  /** Used as default options for `_.truncate`. */
+  var DEFAULT_TRUNC_LENGTH = 30,
+      DEFAULT_TRUNC_OMISSION = '...';
+
+  /** Used to detect hot functions by number of calls within a span of milliseconds. */
+  var HOT_COUNT = 800,
+      HOT_SPAN = 16;
+
+  /** Used to indicate the type of lazy iteratees. */
+  var LAZY_FILTER_FLAG = 1,
+      LAZY_MAP_FLAG = 2,
+      LAZY_WHILE_FLAG = 3;
+
+  /** Used as references for various `Number` constants. */
+  var INFINITY = 1 / 0,
+      MAX_SAFE_INTEGER = 9007199254740991,
+      MAX_INTEGER = 1.7976931348623157e+308,
+      NAN = 0 / 0;
+
+  /** Used as references for the maximum length and index of an array. */
+  var MAX_ARRAY_LENGTH = 4294967295,
+      MAX_ARRAY_INDEX = MAX_ARRAY_LENGTH - 1,
+      HALF_MAX_ARRAY_LENGTH = MAX_ARRAY_LENGTH >>> 1;
+
+  /** Used to associate wrap methods with their bit flags. */
+  var wrapFlags = [
+    ['ary', WRAP_ARY_FLAG],
+    ['bind', WRAP_BIND_FLAG],
+    ['bindKey', WRAP_BIND_KEY_FLAG],
+    ['curry', WRAP_CURRY_FLAG],
+    ['curryRight', WRAP_CURRY_RIGHT_FLAG],
+    ['flip', WRAP_FLIP_FLAG],
+    ['partial', WRAP_PARTIAL_FLAG],
+    ['partialRight', WRAP_PARTIAL_RIGHT_FLAG],
+    ['rearg', WRAP_REARG_FLAG]
+  ];
 
-  /** Used to prefix keys to avoid issues with `__proto__` and properties on `Object.prototype` */
-  var keyPrefix = +new Date + '';
+  /** `Object#toString` result references. */
+  var argsTag = '[object Arguments]',
+      arrayTag = '[object Array]',
+      asyncTag = '[object AsyncFunction]',
+      boolTag = '[object Boolean]',
+      dateTag = '[object Date]',
+      domExcTag = '[object DOMException]',
+      errorTag = '[object Error]',
+      funcTag = '[object Function]',
+      genTag = '[object GeneratorFunction]',
+      mapTag = '[object Map]',
+      numberTag = '[object Number]',
+      nullTag = '[object Null]',
+      objectTag = '[object Object]',
+      promiseTag = '[object Promise]',
+      proxyTag = '[object Proxy]',
+      regexpTag = '[object RegExp]',
+      setTag = '[object Set]',
+      stringTag = '[object String]',
+      symbolTag = '[object Symbol]',
+      undefinedTag = '[object Undefined]',
+      weakMapTag = '[object WeakMap]',
+      weakSetTag = '[object WeakSet]';
+
+  var arrayBufferTag = '[object ArrayBuffer]',
+      dataViewTag = '[object DataView]',
+      float32Tag = '[object Float32Array]',
+      float64Tag = '[object Float64Array]',
+      int8Tag = '[object Int8Array]',
+      int16Tag = '[object Int16Array]',
+      int32Tag = '[object Int32Array]',
+      uint8Tag = '[object Uint8Array]',
+      uint8ClampedTag = '[object Uint8ClampedArray]',
+      uint16Tag = '[object Uint16Array]',
+      uint32Tag = '[object Uint32Array]';
 
-  /** Used as the size when optimizations are enabled for large arrays */
-  var largeArraySize = 75;
+  /** Used to match empty string literals in compiled template source. */
+  var reEmptyStringLeading = /\b__p \+= '';/g,
+      reEmptyStringMiddle = /\b(__p \+=) '' \+/g,
+      reEmptyStringTrailing = /(__e\(.*?\)|\b__t\)) \+\n'';/g;
 
-  /** Used as the max size of the `arrayPool` and `objectPool` */
-  var maxPoolSize = 40;
+  /** Used to match HTML entities and HTML characters. */
+  var reEscapedHtml = /&(?:amp|lt|gt|quot|#39);/g,
+      reUnescapedHtml = /[&<>"']/g,
+      reHasEscapedHtml = RegExp(reEscapedHtml.source),
+      reHasUnescapedHtml = RegExp(reUnescapedHtml.source);
+
+  /** Used to match template delimiters. */
+  var reEscape = /<%-([\s\S]+?)%>/g,
+      reEvaluate = /<%([\s\S]+?)%>/g,
+      reInterpolate = /<%=([\s\S]+?)%>/g;
+
+  /** Used to match property names within property paths. */
+  var reIsDeepProp = /\.|\[(?:[^[\]]*|(["'])(?:(?!\1)[^\\]|\\.)*?\1)\]/,
+      reIsPlainProp = /^\w*$/,
+      rePropName = /[^.[\]]+|\[(?:(-?\d+(?:\.\d+)?)|(["'])((?:(?!\2)[^\\]|\\.)*?)\2)\]|(?=(?:\.|\[\])(?:\.|\[\]|$))/g;
 
-  /** Used to detect and test whitespace */
-  var whitespace = (
-    // whitespace
-    ' \t\x0B\f\xA0\ufeff' +
+  /**
+   * Used to match `RegExp`
+   * [syntax characters](http://ecma-international.org/ecma-262/7.0/#sec-patterns).
+   */
+  var reRegExpChar = /[\\^$.*+?()[\]{}|]/g,
+      reHasRegExpChar = RegExp(reRegExpChar.source);
 
-    // line terminators
-    '\n\r\u2028\u2029' +
+  /** Used to match leading whitespace. */
+  var reTrimStart = /^\s+/;
 
-    // unicode category "Zs" space separators
-    '\u1680\u180e\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u202f\u205f\u3000'
-  );
+  /** Used to match a single whitespace character. */
+  var reWhitespace = /\s/;
 
-  /** Used to match empty string literals in compiled template source */
-  var reEmptyStringLeading = /\b__p \+= '';/g,
-      reEmptyStringMiddle = /\b(__p \+=) '' \+/g,
-      reEmptyStringTrailing = /(__e\(.*?\)|\b__t\)) \+\n'';/g;
+  /** Used to match wrap detail comments. */
+  var reWrapComment = /\{(?:\n\/\* \[wrapped with .+\] \*\/)?\n?/,
+      reWrapDetails = /\{\n\/\* \[wrapped with (.+)\] \*/,
+      reSplitDetails = /,? & /;
+
+  /** Used to match words composed of alphanumeric characters. */
+  var reAsciiWord = /[^\x00-\x2f\x3a-\x40\x5b-\x60\x7b-\x7f]+/g;
 
   /**
-   * Used to match ES6 template delimiters
-   * http://people.mozilla.org/~jorendorff/es6-draft.html#sec-literals-string-literals
+   * Used to validate the `validate` option in `_.template` variable.
+   *
+   * Forbids characters which could potentially change the meaning of the function argument definition:
+   * - "()," (modification of function parameters)
+   * - "=" (default value)
+   * - "[]{}" (destructuring of function parameters)
+   * - "/" (beginning of a comment)
+   * - whitespace
+   */
+  var reForbiddenIdentifierChars = /[()=,{}\[\]\/\s]/;
+
+  /** Used to match backslashes in property paths. */
+  var reEscapeChar = /\\(\\)?/g;
+
+  /**
+   * Used to match
+   * [ES template delimiters](http://ecma-international.org/ecma-262/7.0/#sec-template-literal-lexical-components).
    */
   var reEsTemplate = /\$\{([^\\}]*(?:\\.[^\\}]*)*)\}/g;
 
-  /** Used to match regexp flags from their coerced string values */
+  /** Used to match `RegExp` flags from their coerced string values. */
   var reFlags = /\w*$/;
 
-  /** Used to detected named functions */
-  var reFuncName = /^\s*function[ \n\r\t]+\w/;
+  /** Used to detect bad signed hexadecimal string values. */
+  var reIsBadHex = /^[-+]0x[0-9a-f]+$/i;
+
+  /** Used to detect binary string values. */
+  var reIsBinary = /^0b[01]+$/i;
+
+  /** Used to detect host constructors (Safari). */
+  var reIsHostCtor = /^\[object .+?Constructor\]$/;
+
+  /** Used to detect octal string values. */
+  var reIsOctal = /^0o[0-7]+$/i;
 
-  /** Used to match "interpolate" template delimiters */
-  var reInterpolate = /<%=([\s\S]+?)%>/g;
+  /** Used to detect unsigned integer values. */
+  var reIsUint = /^(?:0|[1-9]\d*)$/;
 
-  /** Used to match leading whitespace and zeros to be removed */
-  var reLeadingSpacesAndZeros = RegExp('^[' + whitespace + ']*0+(?=.$)');
+  /** Used to match Latin Unicode letters (excluding mathematical operators). */
+  var reLatin = /[\xc0-\xd6\xd8-\xf6\xf8-\xff\u0100-\u017f]/g;
 
-  /** Used to ensure capturing order of template delimiters */
+  /** Used to ensure capturing order of template delimiters. */
   var reNoMatch = /($^)/;
 
-  /** Used to detect functions containing a `this` reference */
-  var reThis = /\bthis\b/;
+  /** Used to match unescaped characters in compiled string literals. */
+  var reUnescapedString = /['\n\r\u2028\u2029\\]/g;
 
-  /** Used to match unescaped characters in compiled string literals */
-  var reUnescapedString = /['\n\r\t\u2028\u2029\\]/g;
+  /** Used to compose unicode character classes. */
+  var rsAstralRange = '\\ud800-\\udfff',
+      rsComboMarksRange = '\\u0300-\\u036f',
+      reComboHalfMarksRange = '\\ufe20-\\ufe2f',
+      rsComboSymbolsRange = '\\u20d0-\\u20ff',
+      rsComboRange = rsComboMarksRange + reComboHalfMarksRange + rsComboSymbolsRange,
+      rsDingbatRange = '\\u2700-\\u27bf',
+      rsLowerRange = 'a-z\\xdf-\\xf6\\xf8-\\xff',
+      rsMathOpRange = '\\xac\\xb1\\xd7\\xf7',
+      rsNonCharRange = '\\x00-\\x2f\\x3a-\\x40\\x5b-\\x60\\x7b-\\xbf',
+      rsPunctuationRange = '\\u2000-\\u206f',
+      rsSpaceRange = ' \\t\\x0b\\f\\xa0\\ufeff\\n\\r\\u2028\\u2029\\u1680\\u180e\\u2000\\u2001\\u2002\\u2003\\u2004\\u2005\\u2006\\u2007\\u2008\\u2009\\u200a\\u202f\\u205f\\u3000',
+      rsUpperRange = 'A-Z\\xc0-\\xd6\\xd8-\\xde',
+      rsVarRange = '\\ufe0e\\ufe0f',
+      rsBreakRange = rsMathOpRange + rsNonCharRange + rsPunctuationRange + rsSpaceRange;
+
+  /** Used to compose unicode capture groups. */
+  var rsApos = "['\u2019]",
+      rsAstral = '[' + rsAstralRange + ']',
+      rsBreak = '[' + rsBreakRange + ']',
+      rsCombo = '[' + rsComboRange + ']',
+      rsDigits = '\\d+',
+      rsDingbat = '[' + rsDingbatRange + ']',
+      rsLower = '[' + rsLowerRange + ']',
+      rsMisc = '[^' + rsAstralRange + rsBreakRange + rsDigits + rsDingbatRange + rsLowerRange + rsUpperRange + ']',
+      rsFitz = '\\ud83c[\\udffb-\\udfff]',
+      rsModifier = '(?:' + rsCombo + '|' + rsFitz + ')',
+      rsNonAstral = '[^' + rsAstralRange + ']',
+      rsRegional = '(?:\\ud83c[\\udde6-\\uddff]){2}',
+      rsSurrPair = '[\\ud800-\\udbff][\\udc00-\\udfff]',
+      rsUpper = '[' + rsUpperRange + ']',
+      rsZWJ = '\\u200d';
+
+  /** Used to compose unicode regexes. */
+  var rsMiscLower = '(?:' + rsLower + '|' + rsMisc + ')',
+      rsMiscUpper = '(?:' + rsUpper + '|' + rsMisc + ')',
+      rsOptContrLower = '(?:' + rsApos + '(?:d|ll|m|re|s|t|ve))?',
+      rsOptContrUpper = '(?:' + rsApos + '(?:D|LL|M|RE|S|T|VE))?',
+      reOptMod = rsModifier + '?',
+      rsOptVar = '[' + rsVarRange + ']?',
+      rsOptJoin = '(?:' + rsZWJ + '(?:' + [rsNonAstral, rsRegional, rsSurrPair].join('|') + ')' + rsOptVar + reOptMod + ')*',
+      rsOrdLower = '\\d*(?:1st|2nd|3rd|(?![123])\\dth)(?=\\b|[A-Z_])',
+      rsOrdUpper = '\\d*(?:1ST|2ND|3RD|(?![123])\\dTH)(?=\\b|[a-z_])',
+      rsSeq = rsOptVar + reOptMod + rsOptJoin,
+      rsEmoji = '(?:' + [rsDingbat, rsRegional, rsSurrPair].join('|') + ')' + rsSeq,
+      rsSymbol = '(?:' + [rsNonAstral + rsCombo + '?', rsCombo, rsRegional, rsSurrPair, rsAstral].join('|') + ')';
 
-  /** Used to assign default `context` object properties */
-  var contextProps = [
-    'Array', 'Boolean', 'Date', 'Error', 'Function', 'Math', 'Number', 'Object',
-    'RegExp', 'String', '_', 'attachEvent', 'clearTimeout', 'isFinite', 'isNaN',
-    'parseInt', 'setTimeout'
-  ];
+  /** Used to match apostrophes. */
+  var reApos = RegExp(rsApos, 'g');
 
-  /** Used to fix the JScript [[DontEnum]] bug */
-  var shadowedProps = [
-    'constructor', 'hasOwnProperty', 'isPrototypeOf', 'propertyIsEnumerable',
-    'toLocaleString', 'toString', 'valueOf'
-  ];
+  /**
+   * Used to match [combining diacritical marks](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks) and
+   * [combining diacritical marks for symbols](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks_for_Symbols).
+   */
+  var reComboMark = RegExp(rsCombo, 'g');
 
-  /** Used to make template sourceURLs easier to identify */
-  var templateCounter = 0;
+  /** Used to match [string symbols](https://mathiasbynens.be/notes/javascript-unicode). */
+  var reUnicode = RegExp(rsFitz + '(?=' + rsFitz + ')|' + rsSymbol + rsSeq, 'g');
 
-  /** `Object#toString` result shortcuts */
-  var argsClass = '[object Arguments]',
-      arrayClass = '[object Array]',
-      boolClass = '[object Boolean]',
-      dateClass = '[object Date]',
-      errorClass = '[object Error]',
-      funcClass = '[object Function]',
-      numberClass = '[object Number]',
-      objectClass = '[object Object]',
-      regexpClass = '[object RegExp]',
-      stringClass = '[object String]';
-
-  /** Used to identify object classifications that `_.clone` supports */
-  var cloneableClasses = {};
-  cloneableClasses[funcClass] = false;
-  cloneableClasses[argsClass] = cloneableClasses[arrayClass] =
-  cloneableClasses[boolClass] = cloneableClasses[dateClass] =
-  cloneableClasses[numberClass] = cloneableClasses[objectClass] =
-  cloneableClasses[regexpClass] = cloneableClasses[stringClass] = true;
-
-  /** Used as an internal `_.debounce` options object */
-  var debounceOptions = {
-    'leading': false,
-    'maxWait': 0,
-    'trailing': false
-  };
+  /** Used to match complex or compound words. */
+  var reUnicodeWord = RegExp([
+    rsUpper + '?' + rsLower + '+' + rsOptContrLower + '(?=' + [rsBreak, rsUpper, '$'].join('|') + ')',
+    rsMiscUpper + '+' + rsOptContrUpper + '(?=' + [rsBreak, rsUpper + rsMiscLower, '$'].join('|') + ')',
+    rsUpper + '?' + rsMiscLower + '+' + rsOptContrLower,
+    rsUpper + '+' + rsOptContrUpper,
+    rsOrdUpper,
+    rsOrdLower,
+    rsDigits,
+    rsEmoji
+  ].join('|'), 'g');
 
-  /** Used as the property descriptor for `__bindData__` */
-  var descriptor = {
-    'configurable': false,
-    'enumerable': false,
-    'value': null,
-    'writable': false
+  /** Used to detect strings with [zero-width joiners or code points from the astral planes](http://eev.ee/blog/2015/09/12/dark-corners-of-unicode/). */
+  var reHasUnicode = RegExp('[' + rsZWJ + rsAstralRange  + rsComboRange + rsVarRange + ']');
+
+  /** Used to detect strings that need a more robust regexp to match words. */
+  var reHasUnicodeWord = /[a-z][A-Z]|[A-Z]{2}[a-z]|[0-9][a-zA-Z]|[a-zA-Z][0-9]|[^a-zA-Z0-9 ]/;
+
+  /** Used to assign default `context` object properties. */
+  var contextProps = [
+    'Array', 'Buffer', 'DataView', 'Date', 'Error', 'Float32Array', 'Float64Array',
+    'Function', 'Int8Array', 'Int16Array', 'Int32Array', 'Map', 'Math', 'Object',
+    'Promise', 'RegExp', 'Set', 'String', 'Symbol', 'TypeError', 'Uint8Array',
+    'Uint8ClampedArray', 'Uint16Array', 'Uint32Array', 'WeakMap',
+    '_', 'clearTimeout', 'isFinite', 'parseInt', 'setTimeout'
+  ];
+
+  /** Used to make template sourceURLs easier to identify. */
+  var templateCounter = -1;
+
+  /** Used to identify `toStringTag` values of typed arrays. */
+  var typedArrayTags = {};
+  typedArrayTags[float32Tag] = typedArrayTags[float64Tag] =
+  typedArrayTags[int8Tag] = typedArrayTags[int16Tag] =
+  typedArrayTags[int32Tag] = typedArrayTags[uint8Tag] =
+  typedArrayTags[uint8ClampedTag] = typedArrayTags[uint16Tag] =
+  typedArrayTags[uint32Tag] = true;
+  typedArrayTags[argsTag] = typedArrayTags[arrayTag] =
+  typedArrayTags[arrayBufferTag] = typedArrayTags[boolTag] =
+  typedArrayTags[dataViewTag] = typedArrayTags[dateTag] =
+  typedArrayTags[errorTag] = typedArrayTags[funcTag] =
+  typedArrayTags[mapTag] = typedArrayTags[numberTag] =
+  typedArrayTags[objectTag] = typedArrayTags[regexpTag] =
+  typedArrayTags[setTag] = typedArrayTags[stringTag] =
+  typedArrayTags[weakMapTag] = false;
+
+  /** Used to identify `toStringTag` values supported by `_.clone`. */
+  var cloneableTags = {};
+  cloneableTags[argsTag] = cloneableTags[arrayTag] =
+  cloneableTags[arrayBufferTag] = cloneableTags[dataViewTag] =
+  cloneableTags[boolTag] = cloneableTags[dateTag] =
+  cloneableTags[float32Tag] = cloneableTags[float64Tag] =
+  cloneableTags[int8Tag] = cloneableTags[int16Tag] =
+  cloneableTags[int32Tag] = cloneableTags[mapTag] =
+  cloneableTags[numberTag] = cloneableTags[objectTag] =
+  cloneableTags[regexpTag] = cloneableTags[setTag] =
+  cloneableTags[stringTag] = cloneableTags[symbolTag] =
+  cloneableTags[uint8Tag] = cloneableTags[uint8ClampedTag] =
+  cloneableTags[uint16Tag] = cloneableTags[uint32Tag] = true;
+  cloneableTags[errorTag] = cloneableTags[funcTag] =
+  cloneableTags[weakMapTag] = false;
+
+  /** Used to map Latin Unicode letters to basic Latin letters. */
+  var deburredLetters = {
+    // Latin-1 Supplement block.
+    '\xc0': 'A',  '\xc1': 'A', '\xc2': 'A', '\xc3': 'A', '\xc4': 'A', '\xc5': 'A',
+    '\xe0': 'a',  '\xe1': 'a', '\xe2': 'a', '\xe3': 'a', '\xe4': 'a', '\xe5': 'a',
+    '\xc7': 'C',  '\xe7': 'c',
+    '\xd0': 'D',  '\xf0': 'd',
+    '\xc8': 'E',  '\xc9': 'E', '\xca': 'E', '\xcb': 'E',
+    '\xe8': 'e',  '\xe9': 'e', '\xea': 'e', '\xeb': 'e',
+    '\xcc': 'I',  '\xcd': 'I', '\xce': 'I', '\xcf': 'I',
+    '\xec': 'i',  '\xed': 'i', '\xee': 'i', '\xef': 'i',
+    '\xd1': 'N',  '\xf1': 'n',
+    '\xd2': 'O',  '\xd3': 'O', '\xd4': 'O', '\xd5': 'O', '\xd6': 'O', '\xd8': 'O',
+    '\xf2': 'o',  '\xf3': 'o', '\xf4': 'o', '\xf5': 'o', '\xf6': 'o', '\xf8': 'o',
+    '\xd9': 'U',  '\xda': 'U', '\xdb': 'U', '\xdc': 'U',
+    '\xf9': 'u',  '\xfa': 'u', '\xfb': 'u', '\xfc': 'u',
+    '\xdd': 'Y',  '\xfd': 'y', '\xff': 'y',
+    '\xc6': 'Ae', '\xe6': 'ae',
+    '\xde': 'Th', '\xfe': 'th',
+    '\xdf': 'ss',
+    // Latin Extended-A block.
+    '\u0100': 'A',  '\u0102': 'A', '\u0104': 'A',
+    '\u0101': 'a',  '\u0103': 'a', '\u0105': 'a',
+    '\u0106': 'C',  '\u0108': 'C', '\u010a': 'C', '\u010c': 'C',
+    '\u0107': 'c',  '\u0109': 'c', '\u010b': 'c', '\u010d': 'c',
+    '\u010e': 'D',  '\u0110': 'D', '\u010f': 'd', '\u0111': 'd',
+    '\u0112': 'E',  '\u0114': 'E', '\u0116': 'E', '\u0118': 'E', '\u011a': 'E',
+    '\u0113': 'e',  '\u0115': 'e', '\u0117': 'e', '\u0119': 'e', '\u011b': 'e',
+    '\u011c': 'G',  '\u011e': 'G', '\u0120': 'G', '\u0122': 'G',
+    '\u011d': 'g',  '\u011f': 'g', '\u0121': 'g', '\u0123': 'g',
+    '\u0124': 'H',  '\u0126': 'H', '\u0125': 'h', '\u0127': 'h',
+    '\u0128': 'I',  '\u012a': 'I', '\u012c': 'I', '\u012e': 'I', '\u0130': 'I',
+    '\u0129': 'i',  '\u012b': 'i', '\u012d': 'i', '\u012f': 'i', '\u0131': 'i',
+    '\u0134': 'J',  '\u0135': 'j',
+    '\u0136': 'K',  '\u0137': 'k', '\u0138': 'k',
+    '\u0139': 'L',  '\u013b': 'L', '\u013d': 'L', '\u013f': 'L', '\u0141': 'L',
+    '\u013a': 'l',  '\u013c': 'l', '\u013e': 'l', '\u0140': 'l', '\u0142': 'l',
+    '\u0143': 'N',  '\u0145': 'N', '\u0147': 'N', '\u014a': 'N',
+    '\u0144': 'n',  '\u0146': 'n', '\u0148': 'n', '\u014b': 'n',
+    '\u014c': 'O',  '\u014e': 'O', '\u0150': 'O',
+    '\u014d': 'o',  '\u014f': 'o', '\u0151': 'o',
+    '\u0154': 'R',  '\u0156': 'R', '\u0158': 'R',
+    '\u0155': 'r',  '\u0157': 'r', '\u0159': 'r',
+    '\u015a': 'S',  '\u015c': 'S', '\u015e': 'S', '\u0160': 'S',
+    '\u015b': 's',  '\u015d': 's', '\u015f': 's', '\u0161': 's',
+    '\u0162': 'T',  '\u0164': 'T', '\u0166': 'T',
+    '\u0163': 't',  '\u0165': 't', '\u0167': 't',
+    '\u0168': 'U',  '\u016a': 'U', '\u016c': 'U', '\u016e': 'U', '\u0170': 'U', '\u0172': 'U',
+    '\u0169': 'u',  '\u016b': 'u', '\u016d': 'u', '\u016f': 'u', '\u0171': 'u', '\u0173': 'u',
+    '\u0174': 'W',  '\u0175': 'w',
+    '\u0176': 'Y',  '\u0177': 'y', '\u0178': 'Y',
+    '\u0179': 'Z',  '\u017b': 'Z', '\u017d': 'Z',
+    '\u017a': 'z',  '\u017c': 'z', '\u017e': 'z',
+    '\u0132': 'IJ', '\u0133': 'ij',
+    '\u0152': 'Oe', '\u0153': 'oe',
+    '\u0149': "'n", '\u017f': 's'
   };
 
-  /** Used as the data object for `iteratorTemplate` */
-  var iteratorData = {
-    'args': '',
-    'array': null,
-    'bottom': '',
-    'firstArg': '',
-    'init': '',
-    'keys': null,
-    'loop': '',
-    'shadowedProps': null,
-    'support': null,
-    'top': '',
-    'useHas': false
+  /** Used to map characters to HTML entities. */
+  var htmlEscapes = {
+    '&': '&amp;',
+    '<': '&lt;',
+    '>': '&gt;',
+    '"': '&quot;',
+    "'": '&#39;'
   };
 
-  /** Used to determine if values are of the language type Object */
-  var objectTypes = {
-    'boolean': false,
-    'function': true,
-    'object': true,
-    'number': false,
-    'string': false,
-    'undefined': false
+  /** Used to map HTML entities to characters. */
+  var htmlUnescapes = {
+    '&amp;': '&',
+    '&lt;': '<',
+    '&gt;': '>',
+    '&quot;': '"',
+    '&#39;': "'"
   };
 
-  /** Used to escape characters for inclusion in compiled string literals */
+  /** Used to escape characters for inclusion in compiled string literals. */
   var stringEscapes = {
     '\\': '\\',
     "'": "'",
     '\n': 'n',
     '\r': 'r',
-    '\t': 't',
     '\u2028': 'u2028',
     '\u2029': 'u2029'
   };
 
-  /** Used as a reference to the global object */
-  var root = (objectTypes[typeof window] && window) || this;
+  /** Built-in method references without a dependency on `root`. */
+  var freeParseFloat = parseFloat,
+      freeParseInt = parseInt;
 
-  /** Detect free variable `exports` */
-  var freeExports = objectTypes[typeof exports] && exports && !exports.nodeType && exports;
+  /** Detect free variable `global` from Node.js. */
+  var freeGlobal = typeof global == 'object' && global && global.Object === Object && global;
 
-  /** Detect free variable `module` */
-  var freeModule = objectTypes[typeof module] && module && !module.nodeType && module;
+  /** Detect free variable `self`. */
+  var freeSelf = typeof self == 'object' && self && self.Object === Object && self;
 
-  /** Detect the popular CommonJS extension `module.exports` */
-  var moduleExports = freeModule && freeModule.exports === freeExports && freeExports;
-
-  /** Detect free variable `global` from Node.js or Browserified code and use it as `root` */
-  var freeGlobal = objectTypes[typeof global] && global;
-  if (freeGlobal && (freeGlobal.global === freeGlobal || freeGlobal.window === freeGlobal)) {
-    root = freeGlobal;
-  }
+  /** Used as a reference to the global object. */
+  var root = freeGlobal || freeSelf || Function('return this')();
+
+  /** Detect free variable `exports`. */
+  var freeExports = typeof exports == 'object' && exports && !exports.nodeType && exports;
+
+  /** Detect free variable `module`. */
+  var freeModule = freeExports && typeof module == 'object' && module && !module.nodeType && module;
+
+  /** Detect the popular CommonJS extension `module.exports`. */
+  var moduleExports = freeModule && freeModule.exports === freeExports;
+
+  /** Detect free variable `process` from Node.js. */
+  var freeProcess = moduleExports && freeGlobal.process;
+
+  /** Used to access faster Node.js helpers. */
+  var nodeUtil = (function() {
+    try {
+      // Use `util.types` for Node.js 10+.
+      var types = freeModule && freeModule.require && freeModule.require('util').types;
+
+      if (types) {
+        return types;
+      }
+
+      // Legacy `process.binding('util')` for Node.js < 10.
+      return freeProcess && freeProcess.binding && freeProcess.binding('util');
+    } catch (e) {}
+  }());
+
+  /* Node.js helper references. */
+  var nodeIsArrayBuffer = nodeUtil && nodeUtil.isArrayBuffer,
+      nodeIsDate = nodeUtil && nodeUtil.isDate,
+      nodeIsMap = nodeUtil && nodeUtil.isMap,
+      nodeIsRegExp = nodeUtil && nodeUtil.isRegExp,
+      nodeIsSet = nodeUtil && nodeUtil.isSet,
+      nodeIsTypedArray = nodeUtil && nodeUtil.isTypedArray;
 
   /*--------------------------------------------------------------------------*/
 
   /**
-   * The base implementation of `_.indexOf` without support for binary searches
-   * or `fromIndex` constraints.
+   * A faster alternative to `Function#apply`, this function invokes `func`
+   * with the `this` binding of `thisArg` and the arguments of `args`.
    *
    * @private
-   * @param {Array} array The array to search.
-   * @param {*} value The value to search for.
-   * @param {number} [fromIndex=0] The index to search from.
-   * @returns {number} Returns the index of the matched value or `-1`.
+   * @param {Function} func The function to invoke.
+   * @param {*} thisArg The `this` binding of `func`.
+   * @param {Array} args The arguments to invoke `func` with.
+   * @returns {*} Returns the result of `func`.
    */
-  function baseIndexOf(array, value, fromIndex) {
-    var index = (fromIndex || 0) - 1,
-        length = array ? array.length : 0;
+  function apply(func, thisArg, args) {
+    switch (args.length) {
+      case 0: return func.call(thisArg);
+      case 1: return func.call(thisArg, args[0]);
+      case 2: return func.call(thisArg, args[0], args[1]);
+      case 3: return func.call(thisArg, args[0], args[1], args[2]);
+    }
+    return func.apply(thisArg, args);
+  }
+
+  /**
+   * A specialized version of `baseAggregator` for arrays.
+   *
+   * @private
+   * @param {Array} [array] The array to iterate over.
+   * @param {Function} setter The function to set `accumulator` values.
+   * @param {Function} iteratee The iteratee to transform keys.
+   * @param {Object} accumulator The initial aggregated object.
+   * @returns {Function} Returns `accumulator`.
+   */
+  function arrayAggregator(array, setter, iteratee, accumulator) {
+    var index = -1,
+        length = array == null ? 0 : array.length;
 
     while (++index < length) {
-      if (array[index] === value) {
-        return index;
-      }
+      var value = array[index];
+      setter(accumulator, value, iteratee(value), array);
     }
-    return -1;
+    return accumulator;
   }
 
   /**
-   * An implementation of `_.contains` for cache objects that mimics the return
-   * signature of `_.indexOf` by returning `0` if the value is found, else `-1`.
+   * A specialized version of `_.forEach` for arrays without support for
+   * iteratee shorthands.
    *
    * @private
-   * @param {Object} cache The cache object to inspect.
-   * @param {*} value The value to search for.
-   * @returns {number} Returns `0` if `value` is found, else `-1`.
+   * @param {Array} [array] The array to iterate over.
+   * @param {Function} iteratee The function invoked per iteration.
+   * @returns {Array} Returns `array`.
    */
-  function cacheIndexOf(cache, value) {
-    var type = typeof value;
-    cache = cache.cache;
+  function arrayEach(array, iteratee) {
+    var index = -1,
+        length = array == null ? 0 : array.length;
 
-    if (type == 'boolean' || value == null) {
-      return cache[value] ? 0 : -1;
-    }
-    if (type != 'number' && type != 'string') {
-      type = 'object';
+    while (++index < length) {
+      if (iteratee(array[index], index, array) === false) {
+        break;
+      }
     }
-    var key = type == 'number' ? value : keyPrefix + value;
-    cache = (cache = cache[type]) && cache[key];
+    return array;
+  }
 
-    return type == 'object'
-      ? (cache && baseIndexOf(cache, value) > -1 ? 0 : -1)
-      : (cache ? 0 : -1);
+  /**
+   * A specialized version of `_.forEachRight` for arrays without support for
+   * iteratee shorthands.
+   *
+   * @private
+   * @param {Array} [array] The array to iterate over.
+   * @param {Function} iteratee The function invoked per iteration.
+   * @returns {Array} Returns `array`.
+   */
+  function arrayEachRight(array, iteratee) {
+    var length = array == null ? 0 : array.length;
+
+    while (length--) {
+      if (iteratee(array[length], length, array) === false) {
+        break;
+      }
+    }
+    return array;
   }
 
   /**
-   * Adds a given value to the corresponding cache object.
+   * A specialized version of `_.every` for arrays without support for
+   * iteratee shorthands.
    *
    * @private
-   * @param {*} value The value to add to the cache.
+   * @param {Array} [array] The array to iterate over.
+   * @param {Function} predicate The function invoked per iteration.
+   * @returns {boolean} Returns `true` if all elements pass the predicate check,
+   *  else `false`.
    */
-  function cachePush(value) {
-    var cache = this.cache,
-        type = typeof value;
+  function arrayEvery(array, predicate) {
+    var index = -1,
+        length = array == null ? 0 : array.length;
 
-    if (type == 'boolean' || value == null) {
-      cache[value] = true;
-    } else {
-      if (type != 'number' && type != 'string') {
-        type = 'object';
+    while (++index < length) {
+      if (!predicate(array[index], index, array)) {
+        return false;
       }
-      var key = type == 'number' ? value : keyPrefix + value,
-          typeCache = cache[type] || (cache[type] = {});
+    }
+    return true;
+  }
 
-      if (type == 'object') {
-        (typeCache[key] || (typeCache[key] = [])).push(value);
-      } else {
-        typeCache[key] = true;
+  /**
+   * A specialized version of `_.filter` for arrays without support for
+   * iteratee shorthands.
+   *
+   * @private
+   * @param {Array} [array] The array to iterate over.
+   * @param {Function} predicate The function invoked per iteration.
+   * @returns {Array} Returns the new filtered array.
+   */
+  function arrayFilter(array, predicate) {
+    var index = -1,
+        length = array == null ? 0 : array.length,
+        resIndex = 0,
+        result = [];
+
+    while (++index < length) {
+      var value = array[index];
+      if (predicate(value, index, array)) {
+        result[resIndex++] = value;
       }
     }
+    return result;
   }
 
   /**
-   * Used by `_.max` and `_.min` as the default callback when a given
-   * collection is a string value.
+   * A specialized version of `_.includes` for arrays without support for
+   * specifying an index to search from.
    *
    * @private
-   * @param {string} value The character to inspect.
-   * @returns {number} Returns the code unit of given character.
+   * @param {Array} [array] The array to inspect.
+   * @param {*} target The value to search for.
+   * @returns {boolean} Returns `true` if `target` is found, else `false`.
    */
-  function charAtCallback(value) {
-    return value.charCodeAt(0);
+  function arrayIncludes(array, value) {
+    var length = array == null ? 0 : array.length;
+    return !!length && baseIndexOf(array, value, 0) > -1;
   }
 
   /**
-   * Used by `sortBy` to compare transformed `collection` elements, stable sorting
-   * them in ascending order.
+   * This function is like `arrayIncludes` except that it accepts a comparator.
    *
    * @private
-   * @param {Object} a The object to compare to `b`.
-   * @param {Object} b The object to compare to `a`.
-   * @returns {number} Returns the sort order indicator of `1` or `-1`.
+   * @param {Array} [array] The array to inspect.
+   * @param {*} target The value to search for.
+   * @param {Function} comparator The comparator invoked per element.
+   * @returns {boolean} Returns `true` if `target` is found, else `false`.
    */
-  function compareAscending(a, b) {
-    var ac = a.criteria,
-        bc = b.criteria,
-        index = -1,
-        length = ac.length;
+  function arrayIncludesWith(array, value, comparator) {
+    var index = -1,
+        length = array == null ? 0 : array.length;
 
     while (++index < length) {
-      var value = ac[index],
-          other = bc[index];
-
-      if (value !== other) {
-        if (value > other || typeof value == 'undefined') {
-          return 1;
-        }
-        if (value < other || typeof other == 'undefined') {
-          return -1;
-        }
+      if (comparator(value, array[index])) {
+        return true;
       }
     }
-    // Fixes an `Array#sort` bug in the JS engine embedded in Adobe applications
-    // that causes it, under certain circumstances, to return the same value for
-    // `a` and `b`. See https://github.com/jashkenas/underscore/pull/1247
-    //
-    // This also ensures a stable sort in V8 and other engines.
-    // See http://code.google.com/p/v8/issues/detail?id=90
-    return a.index - b.index;
+    return false;
   }
 
   /**
-   * Creates a cache object to optimize linear searches of large arrays.
+   * A specialized version of `_.map` for arrays without support for iteratee
+   * shorthands.
    *
    * @private
-   * @param {Array} [array=[]] The array to search.
-   * @returns {null|Object} Returns the cache object or `null` if caching should not be used.
+   * @param {Array} [array] The array to iterate over.
+   * @param {Function} iteratee The function invoked per iteration.
+   * @returns {Array} Returns the new mapped array.
    */
-  function createCache(array) {
+  function arrayMap(array, iteratee) {
     var index = -1,
-        length = array.length,
-        first = array[0],
-        mid = array[(length / 2) | 0],
-        last = array[length - 1];
+        length = array == null ? 0 : array.length,
+        result = Array(length);
 
-    if (first && typeof first == 'object' &&
-        mid && typeof mid == 'object' && last && typeof last == 'object') {
-      return false;
+    while (++index < length) {
+      result[index] = iteratee(array[index], index, array);
     }
-    var cache = getObject();
-    cache['false'] = cache['null'] = cache['true'] = cache['undefined'] = false;
+    return result;
+  }
 
-    var result = getObject();
-    result.array = array;
-    result.cache = cache;
-    result.push = cachePush;
+  /**
+   * Appends the elements of `values` to `array`.
+   *
+   * @private
+   * @param {Array} array The array to modify.
+   * @param {Array} values The values to append.
+   * @returns {Array} Returns `array`.
+   */
+  function arrayPush(array, values) {
+    var index = -1,
+        length = values.length,
+        offset = array.length;
 
     while (++index < length) {
-      result.push(array[index]);
+      array[offset + index] = values[index];
     }
+    return array;
+  }
+
+  /**
+   * A specialized version of `_.reduce` for arrays without support for
+   * iteratee shorthands.
+   *
+   * @private
+   * @param {Array} [array] The array to iterate over.
+   * @param {Function} iteratee The function invoked per iteration.
+   * @param {*} [accumulator] The initial value.
+   * @param {boolean} [initAccum] Specify using the first element of `array` as
+   *  the initial value.
+   * @returns {*} Returns the accumulated value.
+   */
+  function arrayReduce(array, iteratee, accumulator, initAccum) {
+    var index = -1,
+        length = array == null ? 0 : array.length;
+
+    if (initAccum && length) {
+      accumulator = array[++index];
+    }
+    while (++index < length) {
+      accumulator = iteratee(accumulator, array[index], index, array);
+    }
+    return accumulator;
+  }
+
+  /**
+   * A specialized version of `_.reduceRight` for arrays without support for
+   * iteratee shorthands.
+   *
+   * @private
+   * @param {Array} [array] The array to iterate over.
+   * @param {Function} iteratee The function invoked per iteration.
+   * @param {*} [accumulator] The initial value.
+   * @param {boolean} [initAccum] Specify using the last element of `array` as
+   *  the initial value.
+   * @returns {*} Returns the accumulated value.
+   */
+  function arrayReduceRight(array, iteratee, accumulator, initAccum) {
+    var length = array == null ? 0 : array.length;
+    if (initAccum && length) {
+      accumulator = array[--length];
+    }
+    while (length--) {
+      accumulator = iteratee(accumulator, array[length], length, array);
+    }
+    return accumulator;
+  }
+
+  /**
+   * A specialized version of `_.some` for arrays without support for iteratee
+   * shorthands.
+   *
+   * @private
+   * @param {Array} [array] The array to iterate over.
+   * @param {Function} predicate The function invoked per iteration.
+   * @returns {boolean} Returns `true` if any element passes the predicate check,
+   *  else `false`.
+   */
+  function arraySome(array, predicate) {
+    var index = -1,
+        length = array == null ? 0 : array.length;
+
+    while (++index < length) {
+      if (predicate(array[index], index, array)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  /**
+   * Gets the size of an ASCII `string`.
+   *
+   * @private
+   * @param {string} string The string inspect.
+   * @returns {number} Returns the string size.
+   */
+  var asciiSize = baseProperty('length');
+
+  /**
+   * Converts an ASCII `string` to an array.
+   *
+   * @private
+   * @param {string} string The string to convert.
+   * @returns {Array} Returns the converted array.
+   */
+  function asciiToArray(string) {
+    return string.split('');
+  }
+
+  /**
+   * Splits an ASCII `string` into an array of its words.
+   *
+   * @private
+   * @param {string} The string to inspect.
+   * @returns {Array} Returns the words of `string`.
+   */
+  function asciiWords(string) {
+    return string.match(reAsciiWord) || [];
+  }
+
+  /**
+   * The base implementation of methods like `_.findKey` and `_.findLastKey`,
+   * without support for iteratee shorthands, which iterates over `collection`
+   * using `eachFunc`.
+   *
+   * @private
+   * @param {Array|Object} collection The collection to inspect.
+   * @param {Function} predicate The function invoked per iteration.
+   * @param {Function} eachFunc The function to iterate over `collection`.
+   * @returns {*} Returns the found element or its key, else `undefined`.
+   */
+  function baseFindKey(collection, predicate, eachFunc) {
+    var result;
+    eachFunc(collection, function(value, key, collection) {
+      if (predicate(value, key, collection)) {
+        result = key;
+        return false;
+      }
+    });
     return result;
   }
 
   /**
-   * Used by `template` to escape characters for inclusion in compiled
-   * string literals.
+   * The base implementation of `_.findIndex` and `_.findLastIndex` without
+   * support for iteratee shorthands.
    *
    * @private
-   * @param {string} match The matched character to escape.
-   * @returns {string} Returns the escaped character.
+   * @param {Array} array The array to inspect.
+   * @param {Function} predicate The function invoked per iteration.
+   * @param {number} fromIndex The index to search from.
+   * @param {boolean} [fromRight] Specify iterating from right to left.
+   * @returns {number} Returns the index of the matched value, else `-1`.
    */
-  function escapeStringChar(match) {
-    return '\\' + stringEscapes[match];
+  function baseFindIndex(array, predicate, fromIndex, fromRight) {
+    var length = array.length,
+        index = fromIndex + (fromRight ? 1 : -1);
+
+    while ((fromRight ? index-- : ++index < length)) {
+      if (predicate(array[index], index, array)) {
+        return index;
+      }
+    }
+    return -1;
   }
 
   /**
-   * Gets an array from the array pool or creates a new one if the pool is empty.
+   * The base implementation of `_.indexOf` without `fromIndex` bounds checks.
    *
    * @private
-   * @returns {Array} The array from the pool.
+   * @param {Array} array The array to inspect.
+   * @param {*} value The value to search for.
+   * @param {number} fromIndex The index to search from.
+   * @returns {number} Returns the index of the matched value, else `-1`.
    */
-  function getArray() {
-    return arrayPool.pop() || [];
+  function baseIndexOf(array, value, fromIndex) {
+    return value === value
+      ? strictIndexOf(array, value, fromIndex)
+      : baseFindIndex(array, baseIsNaN, fromIndex);
   }
 
   /**
-   * Gets an object from the object pool or creates a new one if the pool is empty.
+   * This function is like `baseIndexOf` except that it accepts a comparator.
    *
    * @private
-   * @returns {Object} The object from the pool.
+   * @param {Array} array The array to inspect.
+   * @param {*} value The value to search for.
+   * @param {number} fromIndex The index to search from.
+   * @param {Function} comparator The comparator invoked per element.
+   * @returns {number} Returns the index of the matched value, else `-1`.
    */
-  function getObject() {
-    return objectPool.pop() || {
-      'array': null,
-      'cache': null,
-      'criteria': null,
-      'false': false,
-      'index': 0,
-      'null': false,
-      'number': null,
-      'object': null,
-      'push': null,
-      'string': null,
-      'true': false,
-      'undefined': false,
-      'value': null
-    };
+  function baseIndexOfWith(array, value, fromIndex, comparator) {
+    var index = fromIndex - 1,
+        length = array.length;
+
+    while (++index < length) {
+      if (comparator(array[index], value)) {
+        return index;
+      }
+    }
+    return -1;
   }
 
   /**
-   * Checks if `value` is a DOM node in IE < 9.
+   * The base implementation of `_.isNaN` without support for number objects.
    *
    * @private
    * @param {*} value The value to check.
-   * @returns {boolean} Returns `true` if the `value` is a DOM node, else `false`.
+   * @returns {boolean} Returns `true` if `value` is `NaN`, else `false`.
+   */
+  function baseIsNaN(value) {
+    return value !== value;
+  }
+
+  /**
+   * The base implementation of `_.mean` and `_.meanBy` without support for
+   * iteratee shorthands.
+   *
+   * @private
+   * @param {Array} array The array to iterate over.
+   * @param {Function} iteratee The function invoked per iteration.
+   * @returns {number} Returns the mean.
+   */
+  function baseMean(array, iteratee) {
+    var length = array == null ? 0 : array.length;
+    return length ? (baseSum(array, iteratee) / length) : NAN;
+  }
+
+  /**
+   * The base implementation of `_.property` without support for deep paths.
+   *
+   * @private
+   * @param {string} key The key of the property to get.
+   * @returns {Function} Returns the new accessor function.
+   */
+  function baseProperty(key) {
+    return function(object) {
+      return object == null ? undefined : object[key];
+    };
+  }
+
+  /**
+   * The base implementation of `_.propertyOf` without support for deep paths.
+   *
+   * @private
+   * @param {Object} object The object to query.
+   * @returns {Function} Returns the new accessor function.
+   */
+  function basePropertyOf(object) {
+    return function(key) {
+      return object == null ? undefined : object[key];
+    };
+  }
+
+  /**
+   * The base implementation of `_.reduce` and `_.reduceRight`, without support
+   * for iteratee shorthands, which iterates over `collection` using `eachFunc`.
+   *
+   * @private
+   * @param {Array|Object} collection The collection to iterate over.
+   * @param {Function} iteratee The function invoked per iteration.
+   * @param {*} accumulator The initial value.
+   * @param {boolean} initAccum Specify using the first or last element of
+   *  `collection` as the initial value.
+   * @param {Function} eachFunc The function to iterate over `collection`.
+   * @returns {*} Returns the accumulated value.
+   */
+  function baseReduce(collection, iteratee, accumulator, initAccum, eachFunc) {
+    eachFunc(collection, function(value, index, collection) {
+      accumulator = initAccum
+        ? (initAccum = false, value)
+        : iteratee(accumulator, value, index, collection);
+    });
+    return accumulator;
+  }
+
+  /**
+   * The base implementation of `_.sortBy` which uses `comparer` to define the
+   * sort order of `array` and replaces criteria objects with their corresponding
+   * values.
+   *
+   * @private
+   * @param {Array} array The array to sort.
+   * @param {Function} comparer The function to define sort order.
+   * @returns {Array} Returns `array`.
+   */
+  function baseSortBy(array, comparer) {
+    var length = array.length;
+
+    array.sort(comparer);
+    while (length--) {
+      array[length] = array[length].value;
+    }
+    return array;
+  }
+
+  /**
+   * The base implementation of `_.sum` and `_.sumBy` without support for
+   * iteratee shorthands.
+   *
+   * @private
+   * @param {Array} array The array to iterate over.
+   * @param {Function} iteratee The function invoked per iteration.
+   * @returns {number} Returns the sum.
    */
-  function isNode(value) {
-    // IE < 9 presents DOM nodes as `Object` objects except they have `toString`
-    // methods that are `typeof` "string" and still can coerce nodes to strings
-    return typeof value.toString != 'function' && typeof (value + '') == 'string';
+  function baseSum(array, iteratee) {
+    var result,
+        index = -1,
+        length = array.length;
+
+    while (++index < length) {
+      var current = iteratee(array[index]);
+      if (current !== undefined) {
+        result = result === undefined ? current : (result + current);
+      }
+    }
+    return result;
   }
 
   /**
-   * Releases the given array back to the array pool.
+   * The base implementation of `_.times` without support for iteratee shorthands
+   * or max array length checks.
    *
    * @private
-   * @param {Array} [array] The array to release.
+   * @param {number} n The number of times to invoke `iteratee`.
+   * @param {Function} iteratee The function invoked per iteration.
+   * @returns {Array} Returns the array of results.
    */
-  function releaseArray(array) {
-    array.length = 0;
-    if (arrayPool.length < maxPoolSize) {
-      arrayPool.push(array);
+  function baseTimes(n, iteratee) {
+    var index = -1,
+        result = Array(n);
+
+    while (++index < n) {
+      result[index] = iteratee(index);
     }
+    return result;
   }
 
   /**
-   * Releases the given object back to the object pool.
+   * The base implementation of `_.toPairs` and `_.toPairsIn` which creates an array
+   * of key-value pairs for `object` corresponding to the property names of `props`.
    *
    * @private
-   * @param {Object} [object] The object to release.
+   * @param {Object} object The object to query.
+   * @param {Array} props The property names to get values for.
+   * @returns {Object} Returns the key-value pairs.
    */
-  function releaseObject(object) {
-    var cache = object.cache;
-    if (cache) {
-      releaseObject(cache);
+  function baseToPairs(object, props) {
+    return arrayMap(props, function(key) {
+      return [key, object[key]];
+    });
+  }
+
+  /**
+   * The base implementation of `_.trim`.
+   *
+   * @private
+   * @param {string} string The string to trim.
+   * @returns {string} Returns the trimmed string.
+   */
+  function baseTrim(string) {
+    return string
+      ? string.slice(0, trimmedEndIndex(string) + 1).replace(reTrimStart, '')
+      : string;
+  }
+
+  /**
+   * The base implementation of `_.unary` without support for storing metadata.
+   *
+   * @private
+   * @param {Function} func The function to cap arguments for.
+   * @returns {Function} Returns the new capped function.
+   */
+  function baseUnary(func) {
+    return function(value) {
+      return func(value);
+    };
+  }
+
+  /**
+   * The base implementation of `_.values` and `_.valuesIn` which creates an
+   * array of `object` property values corresponding to the property names
+   * of `props`.
+   *
+   * @private
+   * @param {Object} object The object to query.
+   * @param {Array} props The property names to get values for.
+   * @returns {Object} Returns the array of property values.
+   */
+  function baseValues(object, props) {
+    return arrayMap(props, function(key) {
+      return object[key];
+    });
+  }
+
+  /**
+   * Checks if a `cache` value for `key` exists.
+   *
+   * @private
+   * @param {Object} cache The cache to query.
+   * @param {string} key The key of the entry to check.
+   * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
+   */
+  function cacheHas(cache, key) {
+    return cache.has(key);
+  }
+
+  /**
+   * Used by `_.trim` and `_.trimStart` to get the index of the first string symbol
+   * that is not found in the character symbols.
+   *
+   * @private
+   * @param {Array} strSymbols The string symbols to inspect.
+   * @param {Array} chrSymbols The character symbols to find.
+   * @returns {number} Returns the index of the first unmatched string symbol.
+   */
+  function charsStartIndex(strSymbols, chrSymbols) {
+    var index = -1,
+        length = strSymbols.length;
+
+    while (++index < length && baseIndexOf(chrSymbols, strSymbols[index], 0) > -1) {}
+    return index;
+  }
+
+  /**
+   * Used by `_.trim` and `_.trimEnd` to get the index of the last string symbol
+   * that is not found in the character symbols.
+   *
+   * @private
+   * @param {Array} strSymbols The string symbols to inspect.
+   * @param {Array} chrSymbols The character symbols to find.
+   * @returns {number} Returns the index of the last unmatched string symbol.
+   */
+  function charsEndIndex(strSymbols, chrSymbols) {
+    var index = strSymbols.length;
+
+    while (index-- && baseIndexOf(chrSymbols, strSymbols[index], 0) > -1) {}
+    return index;
+  }
+
+  /**
+   * Gets the number of `placeholder` occurrences in `array`.
+   *
+   * @private
+   * @param {Array} array The array to inspect.
+   * @param {*} placeholder The placeholder to search for.
+   * @returns {number} Returns the placeholder count.
+   */
+  function countHolders(array, placeholder) {
+    var length = array.length,
+        result = 0;
+
+    while (length--) {
+      if (array[length] === placeholder) {
+        ++result;
+      }
     }
-    object.array = object.cache = object.criteria = object.object = object.number = object.string = object.value = null;
-    if (objectPool.length < maxPoolSize) {
-      objectPool.push(object);
+    return result;
+  }
+
+  /**
+   * Used by `_.deburr` to convert Latin-1 Supplement and Latin Extended-A
+   * letters to basic Latin letters.
+   *
+   * @private
+   * @param {string} letter The matched letter to deburr.
+   * @returns {string} Returns the deburred letter.
+   */
+  var deburrLetter = basePropertyOf(deburredLetters);
+
+  /**
+   * Used by `_.escape` to convert characters to HTML entities.
+   *
+   * @private
+   * @param {string} chr The matched character to escape.
+   * @returns {string} Returns the escaped character.
+   */
+  var escapeHtmlChar = basePropertyOf(htmlEscapes);
+
+  /**
+   * Used by `_.template` to escape characters for inclusion in compiled string literals.
+   *
+   * @private
+   * @param {string} chr The matched character to escape.
+   * @returns {string} Returns the escaped character.
+   */
+  function escapeStringChar(chr) {
+    return '\\' + stringEscapes[chr];
+  }
+
+  /**
+   * Gets the value at `key` of `object`.
+   *
+   * @private
+   * @param {Object} [object] The object to query.
+   * @param {string} key The key of the property to get.
+   * @returns {*} Returns the property value.
+   */
+  function getValue(object, key) {
+    return object == null ? undefined : object[key];
+  }
+
+  /**
+   * Checks if `string` contains Unicode symbols.
+   *
+   * @private
+   * @param {string} string The string to inspect.
+   * @returns {boolean} Returns `true` if a symbol is found, else `false`.
+   */
+  function hasUnicode(string) {
+    return reHasUnicode.test(string);
+  }
+
+  /**
+   * Checks if `string` contains a word composed of Unicode symbols.
+   *
+   * @private
+   * @param {string} string The string to inspect.
+   * @returns {boolean} Returns `true` if a word is found, else `false`.
+   */
+  function hasUnicodeWord(string) {
+    return reHasUnicodeWord.test(string);
+  }
+
+  /**
+   * Converts `iterator` to an array.
+   *
+   * @private
+   * @param {Object} iterator The iterator to convert.
+   * @returns {Array} Returns the converted array.
+   */
+  function iteratorToArray(iterator) {
+    var data,
+        result = [];
+
+    while (!(data = iterator.next()).done) {
+      result.push(data.value);
     }
+    return result;
   }
 
   /**
-   * Slices the `collection` from the `start` index up to, but not including,
-   * the `end` index.
+   * Converts `map` to its key-value pairs.
    *
-   * Note: This function is used instead of `Array#slice` to support node lists
-   * in IE < 9 and to ensure dense arrays are returned.
+   * @private
+   * @param {Object} map The map to convert.
+   * @returns {Array} Returns the key-value pairs.
+   */
+  function mapToArray(map) {
+    var index = -1,
+        result = Array(map.size);
+
+    map.forEach(function(value, key) {
+      result[++index] = [key, value];
+    });
+    return result;
+  }
+
+  /**
+   * Creates a unary function that invokes `func` with its argument transformed.
+   *
+   * @private
+   * @param {Function} func The function to wrap.
+   * @param {Function} transform The argument transform.
+   * @returns {Function} Returns the new function.
+   */
+  function overArg(func, transform) {
+    return function(arg) {
+      return func(transform(arg));
+    };
+  }
+
+  /**
+   * Replaces all `placeholder` elements in `array` with an internal placeholder
+   * and returns an array of their indexes.
    *
    * @private
-   * @param {Array|Object|string} collection The collection to slice.
-   * @param {number} start The start index.
-   * @param {number} end The end index.
-   * @returns {Array} Returns the new array.
+   * @param {Array} array The array to modify.
+   * @param {*} placeholder The placeholder to replace.
+   * @returns {Array} Returns the new array of placeholder indexes.
    */
-  function slice(array, start, end) {
-    start || (start = 0);
-    if (typeof end == 'undefined') {
-      end = array ? array.length : 0;
+  function replaceHolders(array, placeholder) {
+    var index = -1,
+        length = array.length,
+        resIndex = 0,
+        result = [];
+
+    while (++index < length) {
+      var value = array[index];
+      if (value === placeholder || value === PLACEHOLDER) {
+        array[index] = PLACEHOLDER;
+        result[resIndex++] = index;
+      }
     }
+    return result;
+  }
+
+  /**
+   * Converts `set` to an array of its values.
+   *
+   * @private
+   * @param {Object} set The set to convert.
+   * @returns {Array} Returns the values.
+   */
+  function setToArray(set) {
+    var index = -1,
+        result = Array(set.size);
+
+    set.forEach(function(value) {
+      result[++index] = value;
+    });
+    return result;
+  }
+
+  /**
+   * Converts `set` to its value-value pairs.
+   *
+   * @private
+   * @param {Object} set The set to convert.
+   * @returns {Array} Returns the value-value pairs.
+   */
+  function setToPairs(set) {
     var index = -1,
-        length = end - start || 0,
-        result = Array(length < 0 ? 0 : length);
+        result = Array(set.size);
+
+    set.forEach(function(value) {
+      result[++index] = [value, value];
+    });
+    return result;
+  }
+
+  /**
+   * A specialized version of `_.indexOf` which performs strict equality
+   * comparisons of values, i.e. `===`.
+   *
+   * @private
+   * @param {Array} array The array to inspect.
+   * @param {*} value The value to search for.
+   * @param {number} fromIndex The index to search from.
+   * @returns {number} Returns the index of the matched value, else `-1`.
+   */
+  function strictIndexOf(array, value, fromIndex) {
+    var index = fromIndex - 1,
+        length = array.length;
 
     while (++index < length) {
-      result[index] = array[start + index];
+      if (array[index] === value) {
+        return index;
+      }
+    }
+    return -1;
+  }
+
+  /**
+   * A specialized version of `_.lastIndexOf` which performs strict equality
+   * comparisons of values, i.e. `===`.
+   *
+   * @private
+   * @param {Array} array The array to inspect.
+   * @param {*} value The value to search for.
+   * @param {number} fromIndex The index to search from.
+   * @returns {number} Returns the index of the matched value, else `-1`.
+   */
+  function strictLastIndexOf(array, value, fromIndex) {
+    var index = fromIndex + 1;
+    while (index--) {
+      if (array[index] === value) {
+        return index;
+      }
+    }
+    return index;
+  }
+
+  /**
+   * Gets the number of symbols in `string`.
+   *
+   * @private
+   * @param {string} string The string to inspect.
+   * @returns {number} Returns the string size.
+   */
+  function stringSize(string) {
+    return hasUnicode(string)
+      ? unicodeSize(string)
+      : asciiSize(string);
+  }
+
+  /**
+   * Converts `string` to an array.
+   *
+   * @private
+   * @param {string} string The string to convert.
+   * @returns {Array} Returns the converted array.
+   */
+  function stringToArray(string) {
+    return hasUnicode(string)
+      ? unicodeToArray(string)
+      : asciiToArray(string);
+  }
+
+  /**
+   * Used by `_.trim` and `_.trimEnd` to get the index of the last non-whitespace
+   * character of `string`.
+   *
+   * @private
+   * @param {string} string The string to inspect.
+   * @returns {number} Returns the index of the last non-whitespace character.
+   */
+  function trimmedEndIndex(string) {
+    var index = string.length;
+
+    while (index-- && reWhitespace.test(string.charAt(index))) {}
+    return index;
+  }
+
+  /**
+   * Used by `_.unescape` to convert HTML entities to characters.
+   *
+   * @private
+   * @param {string} chr The matched character to unescape.
+   * @returns {string} Returns the unescaped character.
+   */
+  var unescapeHtmlChar = basePropertyOf(htmlUnescapes);
+
+  /**
+   * Gets the size of a Unicode `string`.
+   *
+   * @private
+   * @param {string} string The string inspect.
+   * @returns {number} Returns the string size.
+   */
+  function unicodeSize(string) {
+    var result = reUnicode.lastIndex = 0;
+    while (reUnicode.test(string)) {
+      ++result;
     }
     return result;
   }
 
+  /**
+   * Converts a Unicode `string` to an array.
+   *
+   * @private
+   * @param {string} string The string to convert.
+   * @returns {Array} Returns the converted array.
+   */
+  function unicodeToArray(string) {
+    return string.match(reUnicode) || [];
+  }
+
+  /**
+   * Splits a Unicode `string` into an array of its words.
+   *
+   * @private
+   * @param {string} The string to inspect.
+   * @returns {Array} Returns the words of `string`.
+   */
+  function unicodeWords(string) {
+    return string.match(reUnicodeWord) || [];
+  }
+
   /*--------------------------------------------------------------------------*/
 
   /**
-   * Create a new `lodash` function using the given context object.
+   * Create a new pristine `lodash` function using the `context` object.
    *
    * @static
    * @memberOf _
-   * @category Utilities
+   * @since 1.1.0
+   * @category Util
    * @param {Object} [context=root] The context object.
-   * @returns {Function} Returns the `lodash` function.
+   * @returns {Function} Returns a new `lodash` function.
+   * @example
+   *
+   * _.mixin({ 'foo': _.constant('foo') });
+   *
+   * var lodash = _.runInContext();
+   * lodash.mixin({ 'bar': lodash.constant('bar') });
+   *
+   * _.isFunction(_.foo);
+   * // => true
+   * _.isFunction(_.bar);
+   * // => false
+   *
+   * lodash.isFunction(lodash.foo);
+   * // => false
+   * lodash.isFunction(lodash.bar);
+   * // => true
+   *
+   * // Create a suped-up `defer` in Node.js.
+   * var defer = _.runInContext({ 'setTimeout': setImmediate }).defer;
    */
-  function runInContext(context) {
-    // Avoid issues with some ES3 environments that attempt to use values, named
-    // after built-in constructors like `Object`, for the creation of literals.
-    // ES5 clears this up by stating that literals must use built-in constructors.
-    // See http://es5.github.io/#x11.1.5.
-    context = context ? _.defaults(root.Object(), context, _.pick(root, contextProps)) : root;
+  var runInContext = (function runInContext(context) {
+    context = context == null ? root : _.defaults(root.Object(), context, _.pick(root, contextProps));
 
-    /** Native constructor references */
+    /** Built-in constructor references. */
     var Array = context.Array,
-        Boolean = context.Boolean,
         Date = context.Date,
         Error = context.Error,
         Function = context.Function,
         Math = context.Math,
-        Number = context.Number,
         Object = context.Object,
         RegExp = context.RegExp,
         String = context.String,
         TypeError = context.TypeError;
 
-    /**
-     * Used for `Array` method references.
-     *
-     * Normally `Array.prototype` would suffice, however, using an array literal
-     * avoids issues in Narwhal.
-     */
-    var arrayRef = [];
-
-    /** Used for native method references */
-    var errorProto = Error.prototype,
-        objectProto = Object.prototype,
-        stringProto = String.prototype;
-
-    /** Used to restore the original `_` reference in `noConflict` */
-    var oldDash = context._;
-
-    /** Used to resolve the internal [[Class]] of values */
-    var toString = objectProto.toString;
+    /** Used for built-in method references. */
+    var arrayProto = Array.prototype,
+        funcProto = Function.prototype,
+        objectProto = Object.prototype;
+
+    /** Used to detect overreaching core-js shims. */
+    var coreJsData = context['__core-js_shared__'];
+
+    /** Used to resolve the decompiled source of functions. */
+    var funcToString = funcProto.toString;
+
+    /** Used to check objects for own properties. */
+    var hasOwnProperty = objectProto.hasOwnProperty;
+
+    /** Used to generate unique IDs. */
+    var idCounter = 0;
+
+    /** Used to detect methods masquerading as native. */
+    var maskSrcKey = (function() {
+      var uid = /[^.]+$/.exec(coreJsData && coreJsData.keys && coreJsData.keys.IE_PROTO || '');
+      return uid ? ('Symbol(src)_1.' + uid) : '';
+    }());
 
-    /** Used to detect if a method is native */
-    var reNative = RegExp('^' +
-      String(toString)
-        .replace(/[.*+?^${}()|[\]\\]/g, '\\$&')
-        .replace(/toString| for [^\]]+/g, '.*?') + '$'
+    /**
+     * Used to resolve the
+     * [`toStringTag`](http://ecma-international.org/ecma-262/7.0/#sec-object.prototype.tostring)
+     * of values.
+     */
+    var nativeObjectToString = objectProto.toString;
+
+    /** Used to infer the `Object` constructor. */
+    var objectCtorString = funcToString.call(Object);
+
+    /** Used to restore the original `_` reference in `_.noConflict`. */
+    var oldDash = root._;
+
+    /** Used to detect if a method is native. */
+    var reIsNative = RegExp('^' +
+      funcToString.call(hasOwnProperty).replace(reRegExpChar, '\\$&')
+      .replace(/hasOwnProperty|(function).*?(?=\\\()| for .+?(?=\\\])/g, '$1.*?') + '$'
     );
 
-    /** Native method shortcuts */
-    var ceil = Math.ceil,
-        clearTimeout = context.clearTimeout,
-        floor = Math.floor,
-        fnToString = Function.prototype.toString,
-        getPrototypeOf = isNative(getPrototypeOf = Object.getPrototypeOf) && getPrototypeOf,
-        hasOwnProperty = objectProto.hasOwnProperty,
-        push = arrayRef.push,
+    /** Built-in value references. */
+    var Buffer = moduleExports ? context.Buffer : undefined,
+        Symbol = context.Symbol,
+        Uint8Array = context.Uint8Array,
+        allocUnsafe = Buffer ? Buffer.allocUnsafe : undefined,
+        getPrototype = overArg(Object.getPrototypeOf, Object),
+        objectCreate = Object.create,
         propertyIsEnumerable = objectProto.propertyIsEnumerable,
-        setTimeout = context.setTimeout,
-        splice = arrayRef.splice,
-        unshift = arrayRef.unshift;
+        splice = arrayProto.splice,
+        spreadableSymbol = Symbol ? Symbol.isConcatSpreadable : undefined,
+        symIterator = Symbol ? Symbol.iterator : undefined,
+        symToStringTag = Symbol ? Symbol.toStringTag : undefined;
 
-    /** Used to set meta data on functions */
     var defineProperty = (function() {
-      // IE 8 only accepts DOM elements
       try {
-        var o = {},
-            func = isNative(func = Object.defineProperty) && func,
-            result = func(o, o, o) && func;
-      } catch(e) { }
-      return result;
+        var func = getNative(Object, 'defineProperty');
+        func({}, '', {});
+        return func;
+      } catch (e) {}
     }());
 
-    /* Native method shortcuts for methods with the same name as other `lodash` methods */
-    var nativeCreate = isNative(nativeCreate = Object.create) && nativeCreate,
-        nativeIsArray = isNative(nativeIsArray = Array.isArray) && nativeIsArray,
+    /** Mocked built-ins. */
+    var ctxClearTimeout = context.clearTimeout !== root.clearTimeout && context.clearTimeout,
+        ctxNow = Date && Date.now !== root.Date.now && Date.now,
+        ctxSetTimeout = context.setTimeout !== root.setTimeout && context.setTimeout;
+
+    /* Built-in method references for those with the same name as other `lodash` methods. */
+    var nativeCeil = Math.ceil,
+        nativeFloor = Math.floor,
+        nativeGetSymbols = Object.getOwnPropertySymbols,
+        nativeIsBuffer = Buffer ? Buffer.isBuffer : undefined,
         nativeIsFinite = context.isFinite,
-        nativeIsNaN = context.isNaN,
-        nativeKeys = isNative(nativeKeys = Object.keys) && nativeKeys,
+        nativeJoin = arrayProto.join,
+        nativeKeys = overArg(Object.keys, Object),
         nativeMax = Math.max,
         nativeMin = Math.min,
+        nativeNow = Date.now,
         nativeParseInt = context.parseInt,
-        nativeRandom = Math.random;
-
-    /** Used to lookup a built-in constructor by [[Class]] */
-    var ctorByClass = {};
-    ctorByClass[arrayClass] = Array;
-    ctorByClass[boolClass] = Boolean;
-    ctorByClass[dateClass] = Date;
-    ctorByClass[funcClass] = Function;
-    ctorByClass[objectClass] = Object;
-    ctorByClass[numberClass] = Number;
-    ctorByClass[regexpClass] = RegExp;
-    ctorByClass[stringClass] = String;
-
-    /** Used to avoid iterating non-enumerable properties in IE < 9 */
-    var nonEnumProps = {};
-    nonEnumProps[arrayClass] = nonEnumProps[dateClass] = nonEnumProps[numberClass] = { 'constructor': true, 'toLocaleString': true, 'toString': true, 'valueOf': true };
-    nonEnumProps[boolClass] = nonEnumProps[stringClass] = { 'constructor': true, 'toString': true, 'valueOf': true };
-    nonEnumProps[errorClass] = nonEnumProps[funcClass] = nonEnumProps[regexpClass] = { 'constructor': true, 'toString': true };
-    nonEnumProps[objectClass] = { 'constructor': true };
-
-    (function() {
-      var length = shadowedProps.length;
-      while (length--) {
-        var key = shadowedProps[length];
-        for (var className in nonEnumProps) {
-          if (hasOwnProperty.call(nonEnumProps, className) && !hasOwnProperty.call(nonEnumProps[className], key)) {
-            nonEnumProps[className][key] = false;
-          }
-        }
-      }
-    }());
-
-    /*--------------------------------------------------------------------------*/
+        nativeRandom = Math.random,
+        nativeReverse = arrayProto.reverse;
 
-    /**
-     * Creates a `lodash` object which wraps the given value to enable intuitive
-     * method chaining.
-     *
-     * In addition to Lo-Dash methods, wrappers also have the following `Array` methods:
-     * `concat`, `join`, `pop`, `push`, `reverse`, `shift`, `slice`, `sort`, `splice`,
-     * and `unshift`
-     *
-     * Chaining is supported in custom builds as long as the `value` method is
-     * implicitly or explicitly included in the build.
-     *
-     * The chainable wrapper functions are:
-     * `after`, `assign`, `bind`, `bindAll`, `bindKey`, `chain`, `compact`,
-     * `compose`, `concat`, `countBy`, `create`, `createCallback`, `curry`,
-     * `debounce`, `defaults`, `defer`, `delay`, `difference`, `filter`, `flatten`,
-     * `forEach`, `forEachRight`, `forIn`, `forInRight`, `forOwn`, `forOwnRight`,
-     * `functions`, `groupBy`, `indexBy`, `initial`, `intersection`, `invert`,
-     * `invoke`, `keys`, `map`, `max`, `memoize`, `merge`, `min`, `object`, `omit`,
-     * `once`, `pairs`, `partial`, `partialRight`, `pick`, `pluck`, `pull`, `push`,
-     * `range`, `reject`, `remove`, `rest`, `reverse`, `shuffle`, `slice`, `sort`,
-     * `sortBy`, `splice`, `tap`, `throttle`, `times`, `toArray`, `transform`,
-     * `union`, `uniq`, `unshift`, `unzip`, `values`, `where`, `without`, `wrap`,
-     * and `zip`
-     *
-     * The non-chainable wrapper functions are:
-     * `clone`, `cloneDeep`, `contains`, `escape`, `every`, `find`, `findIndex`,
-     * `findKey`, `findLast`, `findLastIndex`, `findLastKey`, `has`, `identity`,
-     * `indexOf`, `isArguments`, `isArray`, `isBoolean`, `isDate`, `isElement`,
-     * `isEmpty`, `isEqual`, `isFinite`, `isFunction`, `isNaN`, `isNull`, `isNumber`,
-     * `isObject`, `isPlainObject`, `isRegExp`, `isString`, `isUndefined`, `join`,
-     * `lastIndexOf`, `mixin`, `noConflict`, `parseInt`, `pop`, `random`, `reduce`,
-     * `reduceRight`, `result`, `shift`, `size`, `some`, `sortedIndex`, `runInContext`,
-     * `template`, `unescape`, `uniqueId`, and `value`
-     *
-     * The wrapper functions `first` and `last` return wrapped values when `n` is
-     * provided, otherwise they return unwrapped values.
-     *
-     * Explicit chaining can be enabled by using the `_.chain` method.
+    /* Built-in method references that are verified to be native. */
+    var DataView = getNative(context, 'DataView'),
+        Map = getNative(context, 'Map'),
+        Promise = getNative(context, 'Promise'),
+        Set = getNative(context, 'Set'),
+        WeakMap = getNative(context, 'WeakMap'),
+        nativeCreate = getNative(Object, 'create');
+
+    /** Used to store function metadata. */
+    var metaMap = WeakMap && new WeakMap;
+
+    /** Used to lookup unminified function names. */
+    var realNames = {};
+
+    /** Used to detect maps, sets, and weakmaps. */
+    var dataViewCtorString = toSource(DataView),
+        mapCtorString = toSource(Map),
+        promiseCtorString = toSource(Promise),
+        setCtorString = toSource(Set),
+        weakMapCtorString = toSource(WeakMap);
+
+    /** Used to convert symbols to primitives and strings. */
+    var symbolProto = Symbol ? Symbol.prototype : undefined,
+        symbolValueOf = symbolProto ? symbolProto.valueOf : undefined,
+        symbolToString = symbolProto ? symbolProto.toString : undefined;
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates a `lodash` object which wraps `value` to enable implicit method
+     * chain sequences. Methods that operate on and return arrays, collections,
+     * and functions can be chained together. Methods that retrieve a single value
+     * or may return a primitive value will automatically end the chain sequence
+     * and return the unwrapped value. Otherwise, the value must be unwrapped
+     * with `_#value`.
+     *
+     * Explicit chain sequences, which must be unwrapped with `_#value`, may be
+     * enabled using `_.chain`.
+     *
+     * The execution of chained methods is lazy, that is, it's deferred until
+     * `_#value` is implicitly or explicitly called.
+     *
+     * Lazy evaluation allows several methods to support shortcut fusion.
+     * Shortcut fusion is an optimization to merge iteratee calls; this avoids
+     * the creation of intermediate arrays and can greatly reduce the number of
+     * iteratee executions. Sections of a chain sequence qualify for shortcut
+     * fusion if the section is applied to an array and iteratees accept only
+     * one argument. The heuristic for whether a section qualifies for shortcut
+     * fusion is subject to change.
+     *
+     * Chaining is supported in custom builds as long as the `_#value` method is
+     * directly or indirectly included in the build.
+     *
+     * In addition to lodash methods, wrappers have `Array` and `String` methods.
+     *
+     * The wrapper `Array` methods are:
+     * `concat`, `join`, `pop`, `push`, `shift`, `sort`, `splice`, and `unshift`
+     *
+     * The wrapper `String` methods are:
+     * `replace` and `split`
+     *
+     * The wrapper methods that support shortcut fusion are:
+     * `at`, `compact`, `drop`, `dropRight`, `dropWhile`, `filter`, `find`,
+     * `findLast`, `head`, `initial`, `last`, `map`, `reject`, `reverse`, `slice`,
+     * `tail`, `take`, `takeRight`, `takeRightWhile`, `takeWhile`, and `toArray`
+     *
+     * The chainable wrapper methods are:
+     * `after`, `ary`, `assign`, `assignIn`, `assignInWith`, `assignWith`, `at`,
+     * `before`, `bind`, `bindAll`, `bindKey`, `castArray`, `chain`, `chunk`,
+     * `commit`, `compact`, `concat`, `conforms`, `constant`, `countBy`, `create`,
+     * `curry`, `debounce`, `defaults`, `defaultsDeep`, `defer`, `delay`,
+     * `difference`, `differenceBy`, `differenceWith`, `drop`, `dropRight`,
+     * `dropRightWhile`, `dropWhile`, `extend`, `extendWith`, `fill`, `filter`,
+     * `flatMap`, `flatMapDeep`, `flatMapDepth`, `flatten`, `flattenDeep`,
+     * `flattenDepth`, `flip`, `flow`, `flowRight`, `fromPairs`, `functions`,
+     * `functionsIn`, `groupBy`, `initial`, `intersection`, `intersectionBy`,
+     * `intersectionWith`, `invert`, `invertBy`, `invokeMap`, `iteratee`, `keyBy`,
+     * `keys`, `keysIn`, `map`, `mapKeys`, `mapValues`, `matches`, `matchesProperty`,
+     * `memoize`, `merge`, `mergeWith`, `method`, `methodOf`, `mixin`, `negate`,
+     * `nthArg`, `omit`, `omitBy`, `once`, `orderBy`, `over`, `overArgs`,
+     * `overEvery`, `overSome`, `partial`, `partialRight`, `partition`, `pick`,
+     * `pickBy`, `plant`, `property`, `propertyOf`, `pull`, `pullAll`, `pullAllBy`,
+     * `pullAllWith`, `pullAt`, `push`, `range`, `rangeRight`, `rearg`, `reject`,
+     * `remove`, `rest`, `reverse`, `sampleSize`, `set`, `setWith`, `shuffle`,
+     * `slice`, `sort`, `sortBy`, `splice`, `spread`, `tail`, `take`, `takeRight`,
+     * `takeRightWhile`, `takeWhile`, `tap`, `throttle`, `thru`, `toArray`,
+     * `toPairs`, `toPairsIn`, `toPath`, `toPlainObject`, `transform`, `unary`,
+     * `union`, `unionBy`, `unionWith`, `uniq`, `uniqBy`, `uniqWith`, `unset`,
+     * `unshift`, `unzip`, `unzipWith`, `update`, `updateWith`, `values`,
+     * `valuesIn`, `without`, `wrap`, `xor`, `xorBy`, `xorWith`, `zip`,
+     * `zipObject`, `zipObjectDeep`, and `zipWith`
+     *
+     * The wrapper methods that are **not** chainable by default are:
+     * `add`, `attempt`, `camelCase`, `capitalize`, `ceil`, `clamp`, `clone`,
+     * `cloneDeep`, `cloneDeepWith`, `cloneWith`, `conformsTo`, `deburr`,
+     * `defaultTo`, `divide`, `each`, `eachRight`, `endsWith`, `eq`, `escape`,
+     * `escapeRegExp`, `every`, `find`, `findIndex`, `findKey`, `findLast`,
+     * `findLastIndex`, `findLastKey`, `first`, `floor`, `forEach`, `forEachRight`,
+     * `forIn`, `forInRight`, `forOwn`, `forOwnRight`, `get`, `gt`, `gte`, `has`,
+     * `hasIn`, `head`, `identity`, `includes`, `indexOf`, `inRange`, `invoke`,
+     * `isArguments`, `isArray`, `isArrayBuffer`, `isArrayLike`, `isArrayLikeObject`,
+     * `isBoolean`, `isBuffer`, `isDate`, `isElement`, `isEmpty`, `isEqual`,
+     * `isEqualWith`, `isError`, `isFinite`, `isFunction`, `isInteger`, `isLength`,
+     * `isMap`, `isMatch`, `isMatchWith`, `isNaN`, `isNative`, `isNil`, `isNull`,
+     * `isNumber`, `isObject`, `isObjectLike`, `isPlainObject`, `isRegExp`,
+     * `isSafeInteger`, `isSet`, `isString`, `isUndefined`, `isTypedArray`,
+     * `isWeakMap`, `isWeakSet`, `join`, `kebabCase`, `last`, `lastIndexOf`,
+     * `lowerCase`, `lowerFirst`, `lt`, `lte`, `max`, `maxBy`, `mean`, `meanBy`,
+     * `min`, `minBy`, `multiply`, `noConflict`, `noop`, `now`, `nth`, `pad`,
+     * `padEnd`, `padStart`, `parseInt`, `pop`, `random`, `reduce`, `reduceRight`,
+     * `repeat`, `result`, `round`, `runInContext`, `sample`, `shift`, `size`,
+     * `snakeCase`, `some`, `sortedIndex`, `sortedIndexBy`, `sortedLastIndex`,
+     * `sortedLastIndexBy`, `startCase`, `startsWith`, `stubArray`, `stubFalse`,
+     * `stubObject`, `stubString`, `stubTrue`, `subtract`, `sum`, `sumBy`,
+     * `template`, `times`, `toFinite`, `toInteger`, `toJSON`, `toLength`,
+     * `toLower`, `toNumber`, `toSafeInteger`, `toString`, `toUpper`, `trim`,
+     * `trimEnd`, `trimStart`, `truncate`, `unescape`, `uniqueId`, `upperCase`,
+     * `upperFirst`, `value`, and `words`
      *
      * @name _
      * @constructor
-     * @category Chaining
+     * @category Seq
      * @param {*} value The value to wrap in a `lodash` instance.
-     * @returns {Object} Returns a `lodash` instance.
+     * @returns {Object} Returns the new `lodash` wrapper instance.
      * @example
      *
+     * function square(n) {
+     *   return n * n;
+     * }
+     *
      * var wrapped = _([1, 2, 3]);
      *
-     * // returns an unwrapped value
-     * wrapped.reduce(function(sum, num) {
-     *   return sum + num;
-     * });
+     * // Returns an unwrapped value.
+     * wrapped.reduce(_.add);
      * // => 6
      *
-     * // returns a wrapped value
-     * var squares = wrapped.map(function(num) {
-     *   return num * num;
-     * });
+     * // Returns a wrapped value.
+     * var squares = wrapped.map(square);
      *
      * _.isArray(squares);
      * // => false
@@ -645,176 +1688,73 @@
      * // => true
      */
     function lodash(value) {
-      // don't wrap if already wrapped, even if wrapped by a different `lodash` constructor
-      return (value && typeof value == 'object' && !isArray(value) && hasOwnProperty.call(value, '__wrapped__'))
-       ? value
-       : new lodashWrapper(value);
+      if (isObjectLike(value) && !isArray(value) && !(value instanceof LazyWrapper)) {
+        if (value instanceof LodashWrapper) {
+          return value;
+        }
+        if (hasOwnProperty.call(value, '__wrapped__')) {
+          return wrapperClone(value);
+        }
+      }
+      return new LodashWrapper(value);
     }
 
     /**
-     * A fast path for creating `lodash` wrapper objects.
+     * The base implementation of `_.create` without support for assigning
+     * properties to the created object.
      *
      * @private
-     * @param {*} value The value to wrap in a `lodash` instance.
-     * @param {boolean} chainAll A flag to enable chaining for all methods
-     * @returns {Object} Returns a `lodash` instance.
+     * @param {Object} proto The object to inherit from.
+     * @returns {Object} Returns the new object.
      */
-    function lodashWrapper(value, chainAll) {
-      this.__chain__ = !!chainAll;
-      this.__wrapped__ = value;
-    }
-    // ensure `new lodashWrapper` is an instance of `lodash`
-    lodashWrapper.prototype = lodash.prototype;
+    var baseCreate = (function() {
+      function object() {}
+      return function(proto) {
+        if (!isObject(proto)) {
+          return {};
+        }
+        if (objectCreate) {
+          return objectCreate(proto);
+        }
+        object.prototype = proto;
+        var result = new object;
+        object.prototype = undefined;
+        return result;
+      };
+    }());
 
     /**
-     * An object used to flag environments features.
+     * The function whose prototype chain sequence wrappers inherit from.
      *
-     * @static
-     * @memberOf _
-     * @type Object
+     * @private
      */
-    var support = lodash.support = {};
-
-    (function() {
-      var ctor = function() { this.x = 1; },
-          object = { '0': 1, 'length': 1 },
-          props = [];
-
-      ctor.prototype = { 'valueOf': 1, 'y': 1 };
-      for (var key in new ctor) { props.push(key); }
-      for (key in arguments) { }
-
-      /**
-       * Detect if an `arguments` object's [[Class]] is resolvable (all but Firefox < 4, IE < 9).
-       *
-       * @memberOf _.support
-       * @type boolean
-       */
-      support.argsClass = toString.call(arguments) == argsClass;
-
-      /**
-       * Detect if `arguments` objects are `Object` objects (all but Narwhal and Opera < 10.5).
-       *
-       * @memberOf _.support
-       * @type boolean
-       */
-      support.argsObject = arguments.constructor == Object && !(arguments instanceof Array);
-
-      /**
-       * Detect if `name` or `message` properties of `Error.prototype` are
-       * enumerable by default. (IE < 9, Safari < 5.1)
-       *
-       * @memberOf _.support
-       * @type boolean
-       */
-      support.enumErrorProps = propertyIsEnumerable.call(errorProto, 'message') || propertyIsEnumerable.call(errorProto, 'name');
-
-      /**
-       * Detect if `prototype` properties are enumerable by default.
-       *
-       * Firefox < 3.6, Opera > 9.50 - Opera < 11.60, and Safari < 5.1
-       * (if the prototype or a property on the prototype has been set)
-       * incorrectly sets a function's `prototype` property [[Enumerable]]
-       * value to `true`.
-       *
-       * @memberOf _.support
-       * @type boolean
-       */
-      support.enumPrototypes = propertyIsEnumerable.call(ctor, 'prototype');
-
-      /**
-       * Detect if functions can be decompiled by `Function#toString`
-       * (all but PS3 and older Opera mobile browsers & avoided in Windows 8 apps).
-       *
-       * @memberOf _.support
-       * @type boolean
-       */
-      support.funcDecomp = !isNative(context.WinRTError) && reThis.test(runInContext);
-
-      /**
-       * Detect if `Function#name` is supported (all but IE).
-       *
-       * @memberOf _.support
-       * @type boolean
-       */
-      support.funcNames = typeof Function.name == 'string';
-
-      /**
-       * Detect if `arguments` object indexes are non-enumerable
-       * (Firefox < 4, IE < 9, PhantomJS, Safari < 5.1).
-       *
-       * @memberOf _.support
-       * @type boolean
-       */
-      support.nonEnumArgs = key != 0;
-
-      /**
-       * Detect if properties shadowing those on `Object.prototype` are non-enumerable.
-       *
-       * In IE < 9 an objects own properties, shadowing non-enumerable ones, are
-       * made non-enumerable as well (a.k.a the JScript [[DontEnum]] bug).
-       *
-       * @memberOf _.support
-       * @type boolean
-       */
-      support.nonEnumShadows = !/valueOf/.test(props);
-
-      /**
-       * Detect if own properties are iterated after inherited properties (all but IE < 9).
-       *
-       * @memberOf _.support
-       * @type boolean
-       */
-      support.ownLast = props[0] != 'x';
-
-      /**
-       * Detect if `Array#shift` and `Array#splice` augment array-like objects correctly.
-       *
-       * Firefox < 10, IE compatibility mode, and IE < 9 have buggy Array `shift()`
-       * and `splice()` functions that fail to remove the last element, `value[0]`,
-       * of array-like objects even though the `length` property is set to `0`.
-       * The `shift()` method is buggy in IE 8 compatibility mode, while `splice()`
-       * is buggy regardless of mode in IE < 9 and buggy in compatibility mode in IE 9.
-       *
-       * @memberOf _.support
-       * @type boolean
-       */
-      support.spliceObjects = (arrayRef.splice.call(object, 0, 1), !object[0]);
-
-      /**
-       * Detect lack of support for accessing string characters by index.
-       *
-       * IE < 8 can't access characters by index and IE 8 can only access
-       * characters by index on string literals.
-       *
-       * @memberOf _.support
-       * @type boolean
-       */
-      support.unindexedChars = ('x'[0] + Object('x')[0]) != 'xx';
+    function baseLodash() {
+      // No operation performed.
+    }
 
-      /**
-       * Detect if a DOM node's [[Class]] is resolvable (all but IE < 9)
-       * and that the JS engine errors when attempting to coerce an object to
-       * a string without a `toString` function.
-       *
-       * @memberOf _.support
-       * @type boolean
-       */
-      try {
-        support.nodeClass = !(toString.call(document) == objectClass && !({ 'toString': 0 } + ''));
-      } catch(e) {
-        support.nodeClass = true;
-      }
-    }(1));
+    /**
+     * The base constructor for creating `lodash` wrapper objects.
+     *
+     * @private
+     * @param {*} value The value to wrap.
+     * @param {boolean} [chainAll] Enable explicit method chain sequences.
+     */
+    function LodashWrapper(value, chainAll) {
+      this.__wrapped__ = value;
+      this.__actions__ = [];
+      this.__chain__ = !!chainAll;
+      this.__index__ = 0;
+      this.__values__ = undefined;
+    }
 
     /**
-     * By default, the template delimiters used by Lo-Dash are similar to those in
-     * embedded Ruby (ERB). Change the following template settings to use alternative
-     * delimiters.
+     * By default, the template delimiters used by lodash are like those in
+     * embedded Ruby (ERB) as well as ES2015 template strings. Change the
+     * following template settings to use alternative delimiters.
      *
      * @static
      * @memberOf _
-     * @type Object
+     * @type {Object}
      */
     lodash.templateSettings = {
 
@@ -822,23 +1762,23 @@
        * Used to detect `data` property values to be HTML-escaped.
        *
        * @memberOf _.templateSettings
-       * @type RegExp
+       * @type {RegExp}
        */
-      'escape': /<%-([\s\S]+?)%>/g,
+      'escape': reEscape,
 
       /**
        * Used to detect code to be evaluated.
        *
        * @memberOf _.templateSettings
-       * @type RegExp
+       * @type {RegExp}
        */
-      'evaluate': /<%([\s\S]+?)%>/g,
+      'evaluate': reEvaluate,
 
       /**
        * Used to detect `data` property values to inject.
        *
        * @memberOf _.templateSettings
-       * @type RegExp
+       * @type {RegExp}
        */
       'interpolate': reInterpolate,
 
@@ -846,7 +1786,7 @@
        * Used to reference the data object in the template text.
        *
        * @memberOf _.templateSettings
-       * @type string
+       * @type {string}
        */
       'variable': '',
 
@@ -854,7 +1794,7 @@
        * Used to import variables into the compiled template.
        *
        * @memberOf _.templateSettings
-       * @type Object
+       * @type {Object}
        */
       'imports': {
 
@@ -862,467 +1802,1422 @@
          * A reference to the `lodash` function.
          *
          * @memberOf _.templateSettings.imports
-         * @type Function
+         * @type {Function}
          */
         '_': lodash
       }
     };
 
-    /*--------------------------------------------------------------------------*/
+    // Ensure wrappers are instances of `baseLodash`.
+    lodash.prototype = baseLodash.prototype;
+    lodash.prototype.constructor = lodash;
+
+    LodashWrapper.prototype = baseCreate(baseLodash.prototype);
+    LodashWrapper.prototype.constructor = LodashWrapper;
+
+    /*------------------------------------------------------------------------*/
 
     /**
-     * The template used to create iterator functions.
+     * Creates a lazy wrapper object which wraps `value` to enable lazy evaluation.
      *
      * @private
-     * @param {Object} data The data object used to populate the text.
-     * @returns {string} Returns the interpolated text.
+     * @constructor
+     * @param {*} value The value to wrap.
      */
-    var iteratorTemplate = template(
-      // the `iterable` may be reassigned by the `top` snippet
-      'var index, iterable = <%= firstArg %>, ' +
-      // assign the `result` variable an initial value
-      'result = <%= init %>;\n' +
-      // exit early if the first argument is falsey
-      'if (!iterable) return result;\n' +
-      // add code before the iteration branches
-      '<%= top %>;' +
-
-      // array-like iteration:
-      '<% if (array) { %>\n' +
-      'var length = iterable.length; index = -1;\n' +
-      'if (<%= array %>) {' +
-
-      // add support for accessing string characters by index if needed
-      '  <% if (support.unindexedChars) { %>\n' +
-      '  if (isString(iterable)) {\n' +
-      "    iterable = iterable.split('')\n" +
-      '  }' +
-      '  <% } %>\n' +
-
-      // iterate over the array-like value
-      '  while (++index < length) {\n' +
-      '    <%= loop %>;\n' +
-      '  }\n' +
-      '}\n' +
-      'else {' +
-
-      // object iteration:
-      // add support for iterating over `arguments` objects if needed
-      '  <% } else if (support.nonEnumArgs) { %>\n' +
-      '  var length = iterable.length; index = -1;\n' +
-      '  if (length && isArguments(iterable)) {\n' +
-      '    while (++index < length) {\n' +
-      "      index += '';\n" +
-      '      <%= loop %>;\n' +
-      '    }\n' +
-      '  } else {' +
-      '  <% } %>' +
-
-      // avoid iterating over `prototype` properties in older Firefox, Opera, and Safari
-      '  <% if (support.enumPrototypes) { %>\n' +
-      "  var skipProto = typeof iterable == 'function';\n" +
-      '  <% } %>' +
-
-      // avoid iterating over `Error.prototype` properties in older IE and Safari
-      '  <% if (support.enumErrorProps) { %>\n' +
-      '  var skipErrorProps = iterable === errorProto || iterable instanceof Error;\n' +
-      '  <% } %>' +
-
-      // define conditions used in the loop
-      '  <%' +
-      '    var conditions = [];' +
-      '    if (support.enumPrototypes) { conditions.push(\'!(skipProto && index == "prototype")\'); }' +
-      '    if (support.enumErrorProps)  { conditions.push(\'!(skipErrorProps && (index == "message" || index == "name"))\'); }' +
-      '  %>' +
-
-      // iterate own properties using `Object.keys`
-      '  <% if (useHas && keys) { %>\n' +
-      '  var ownIndex = -1,\n' +
-      '      ownProps = objectTypes[typeof iterable] && keys(iterable),\n' +
-      '      length = ownProps ? ownProps.length : 0;\n\n' +
-      '  while (++ownIndex < length) {\n' +
-      '    index = ownProps[ownIndex];\n<%' +
-      "    if (conditions.length) { %>    if (<%= conditions.join(' && ') %>) {\n  <% } %>" +
-      '    <%= loop %>;' +
-      '    <% if (conditions.length) { %>\n    }<% } %>\n' +
-      '  }' +
-
-      // else using a for-in loop
-      '  <% } else { %>\n' +
-      '  for (index in iterable) {\n<%' +
-      '    if (useHas) { conditions.push("hasOwnProperty.call(iterable, index)"); }' +
-      "    if (conditions.length) { %>    if (<%= conditions.join(' && ') %>) {\n  <% } %>" +
-      '    <%= loop %>;' +
-      '    <% if (conditions.length) { %>\n    }<% } %>\n' +
-      '  }' +
-
-      // Because IE < 9 can't set the `[[Enumerable]]` attribute of an
-      // existing property and the `constructor` property of a prototype
-      // defaults to non-enumerable, Lo-Dash skips the `constructor`
-      // property when it infers it's iterating over a `prototype` object.
-      '    <% if (support.nonEnumShadows) { %>\n\n' +
-      '  if (iterable !== objectProto) {\n' +
-      "    var ctor = iterable.constructor,\n" +
-      '        isProto = iterable === (ctor && ctor.prototype),\n' +
-      '        className = iterable === stringProto ? stringClass : iterable === errorProto ? errorClass : toString.call(iterable),\n' +
-      '        nonEnum = nonEnumProps[className];\n' +
-      '      <% for (k = 0; k < 7; k++) { %>\n' +
-      "    index = '<%= shadowedProps[k] %>';\n" +
-      '    if ((!(isProto && nonEnum[index]) && hasOwnProperty.call(iterable, index))<%' +
-      '        if (!useHas) { %> || (!nonEnum[index] && iterable[index] !== objectProto[index])<% }' +
-      '      %>) {\n' +
-      '      <%= loop %>;\n' +
-      '    }' +
-      '      <% } %>\n' +
-      '  }' +
-      '    <% } %>' +
-      '  <% } %>' +
-      '  <% if (array || support.nonEnumArgs) { %>\n}<% } %>\n' +
-
-      // add code to the bottom of the iteration function
-      '<%= bottom %>;\n' +
-      // finally, return the `result`
-      'return result'
-    );
+    function LazyWrapper(value) {
+      this.__wrapped__ = value;
+      this.__actions__ = [];
+      this.__dir__ = 1;
+      this.__filtered__ = false;
+      this.__iteratees__ = [];
+      this.__takeCount__ = MAX_ARRAY_LENGTH;
+      this.__views__ = [];
+    }
 
-    /*--------------------------------------------------------------------------*/
+    /**
+     * Creates a clone of the lazy wrapper object.
+     *
+     * @private
+     * @name clone
+     * @memberOf LazyWrapper
+     * @returns {Object} Returns the cloned `LazyWrapper` object.
+     */
+    function lazyClone() {
+      var result = new LazyWrapper(this.__wrapped__);
+      result.__actions__ = copyArray(this.__actions__);
+      result.__dir__ = this.__dir__;
+      result.__filtered__ = this.__filtered__;
+      result.__iteratees__ = copyArray(this.__iteratees__);
+      result.__takeCount__ = this.__takeCount__;
+      result.__views__ = copyArray(this.__views__);
+      return result;
+    }
 
     /**
-     * The base implementation of `_.bind` that creates the bound function and
-     * sets its meta data.
+     * Reverses the direction of lazy iteration.
      *
      * @private
-     * @param {Array} bindData The bind data array.
-     * @returns {Function} Returns the new bound function.
+     * @name reverse
+     * @memberOf LazyWrapper
+     * @returns {Object} Returns the new reversed `LazyWrapper` object.
+     */
+    function lazyReverse() {
+      if (this.__filtered__) {
+        var result = new LazyWrapper(this);
+        result.__dir__ = -1;
+        result.__filtered__ = true;
+      } else {
+        result = this.clone();
+        result.__dir__ *= -1;
+      }
+      return result;
+    }
+
+    /**
+     * Extracts the unwrapped value from its lazy wrapper.
+     *
+     * @private
+     * @name value
+     * @memberOf LazyWrapper
+     * @returns {*} Returns the unwrapped value.
+     */
+    function lazyValue() {
+      var array = this.__wrapped__.value(),
+          dir = this.__dir__,
+          isArr = isArray(array),
+          isRight = dir < 0,
+          arrLength = isArr ? array.length : 0,
+          view = getView(0, arrLength, this.__views__),
+          start = view.start,
+          end = view.end,
+          length = end - start,
+          index = isRight ? end : (start - 1),
+          iteratees = this.__iteratees__,
+          iterLength = iteratees.length,
+          resIndex = 0,
+          takeCount = nativeMin(length, this.__takeCount__);
+
+      if (!isArr || (!isRight && arrLength == length && takeCount == length)) {
+        return baseWrapperValue(array, this.__actions__);
+      }
+      var result = [];
+
+      outer:
+      while (length-- && resIndex < takeCount) {
+        index += dir;
+
+        var iterIndex = -1,
+            value = array[index];
+
+        while (++iterIndex < iterLength) {
+          var data = iteratees[iterIndex],
+              iteratee = data.iteratee,
+              type = data.type,
+              computed = iteratee(value);
+
+          if (type == LAZY_MAP_FLAG) {
+            value = computed;
+          } else if (!computed) {
+            if (type == LAZY_FILTER_FLAG) {
+              continue outer;
+            } else {
+              break outer;
+            }
+          }
+        }
+        result[resIndex++] = value;
+      }
+      return result;
+    }
+
+    // Ensure `LazyWrapper` is an instance of `baseLodash`.
+    LazyWrapper.prototype = baseCreate(baseLodash.prototype);
+    LazyWrapper.prototype.constructor = LazyWrapper;
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates a hash object.
+     *
+     * @private
+     * @constructor
+     * @param {Array} [entries] The key-value pairs to cache.
      */
-    function baseBind(bindData) {
-      var func = bindData[0],
-          partialArgs = bindData[2],
-          thisArg = bindData[4];
-
-      function bound() {
-        // `Function#bind` spec
-        // http://es5.github.io/#x15.3.4.5
-        if (partialArgs) {
-          // avoid `arguments` object deoptimizations by using `slice` instead
-          // of `Array.prototype.slice.call` and not assigning `arguments` to a
-          // variable as a ternary expression
-          var args = slice(partialArgs);
-          push.apply(args, arguments);
-        }
-        // mimic the constructor's `return` behavior
-        // http://es5.github.io/#x13.2.2
-        if (this instanceof bound) {
-          // ensure `new bound` is an instance of `func`
-          var thisBinding = baseCreate(func.prototype),
-              result = func.apply(thisBinding, args || arguments);
-          return isObject(result) ? result : thisBinding;
-        }
-        return func.apply(thisArg, args || arguments);
+    function Hash(entries) {
+      var index = -1,
+          length = entries == null ? 0 : entries.length;
+
+      this.clear();
+      while (++index < length) {
+        var entry = entries[index];
+        this.set(entry[0], entry[1]);
       }
-      setBindData(bound, bindData);
-      return bound;
     }
 
     /**
-     * The base implementation of `_.clone` without argument juggling or support
-     * for `thisArg` binding.
+     * Removes all key-value entries from the hash.
      *
      * @private
-     * @param {*} value The value to clone.
-     * @param {boolean} [isDeep=false] Specify a deep clone.
-     * @param {Function} [callback] The function to customize cloning values.
-     * @param {Array} [stackA=[]] Tracks traversed source objects.
-     * @param {Array} [stackB=[]] Associates clones with source counterparts.
-     * @returns {*} Returns the cloned value.
+     * @name clear
+     * @memberOf Hash
      */
-    function baseClone(value, isDeep, callback, stackA, stackB) {
-      if (callback) {
-        var result = callback(value);
-        if (typeof result != 'undefined') {
-          return result;
+    function hashClear() {
+      this.__data__ = nativeCreate ? nativeCreate(null) : {};
+      this.size = 0;
+    }
+
+    /**
+     * Removes `key` and its value from the hash.
+     *
+     * @private
+     * @name delete
+     * @memberOf Hash
+     * @param {Object} hash The hash to modify.
+     * @param {string} key The key of the value to remove.
+     * @returns {boolean} Returns `true` if the entry was removed, else `false`.
+     */
+    function hashDelete(key) {
+      var result = this.has(key) && delete this.__data__[key];
+      this.size -= result ? 1 : 0;
+      return result;
+    }
+
+    /**
+     * Gets the hash value for `key`.
+     *
+     * @private
+     * @name get
+     * @memberOf Hash
+     * @param {string} key The key of the value to get.
+     * @returns {*} Returns the entry value.
+     */
+    function hashGet(key) {
+      var data = this.__data__;
+      if (nativeCreate) {
+        var result = data[key];
+        return result === HASH_UNDEFINED ? undefined : result;
+      }
+      return hasOwnProperty.call(data, key) ? data[key] : undefined;
+    }
+
+    /**
+     * Checks if a hash value for `key` exists.
+     *
+     * @private
+     * @name has
+     * @memberOf Hash
+     * @param {string} key The key of the entry to check.
+     * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
+     */
+    function hashHas(key) {
+      var data = this.__data__;
+      return nativeCreate ? (data[key] !== undefined) : hasOwnProperty.call(data, key);
+    }
+
+    /**
+     * Sets the hash `key` to `value`.
+     *
+     * @private
+     * @name set
+     * @memberOf Hash
+     * @param {string} key The key of the value to set.
+     * @param {*} value The value to set.
+     * @returns {Object} Returns the hash instance.
+     */
+    function hashSet(key, value) {
+      var data = this.__data__;
+      this.size += this.has(key) ? 0 : 1;
+      data[key] = (nativeCreate && value === undefined) ? HASH_UNDEFINED : value;
+      return this;
+    }
+
+    // Add methods to `Hash`.
+    Hash.prototype.clear = hashClear;
+    Hash.prototype['delete'] = hashDelete;
+    Hash.prototype.get = hashGet;
+    Hash.prototype.has = hashHas;
+    Hash.prototype.set = hashSet;
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates an list cache object.
+     *
+     * @private
+     * @constructor
+     * @param {Array} [entries] The key-value pairs to cache.
+     */
+    function ListCache(entries) {
+      var index = -1,
+          length = entries == null ? 0 : entries.length;
+
+      this.clear();
+      while (++index < length) {
+        var entry = entries[index];
+        this.set(entry[0], entry[1]);
+      }
+    }
+
+    /**
+     * Removes all key-value entries from the list cache.
+     *
+     * @private
+     * @name clear
+     * @memberOf ListCache
+     */
+    function listCacheClear() {
+      this.__data__ = [];
+      this.size = 0;
+    }
+
+    /**
+     * Removes `key` and its value from the list cache.
+     *
+     * @private
+     * @name delete
+     * @memberOf ListCache
+     * @param {string} key The key of the value to remove.
+     * @returns {boolean} Returns `true` if the entry was removed, else `false`.
+     */
+    function listCacheDelete(key) {
+      var data = this.__data__,
+          index = assocIndexOf(data, key);
+
+      if (index < 0) {
+        return false;
+      }
+      var lastIndex = data.length - 1;
+      if (index == lastIndex) {
+        data.pop();
+      } else {
+        splice.call(data, index, 1);
+      }
+      --this.size;
+      return true;
+    }
+
+    /**
+     * Gets the list cache value for `key`.
+     *
+     * @private
+     * @name get
+     * @memberOf ListCache
+     * @param {string} key The key of the value to get.
+     * @returns {*} Returns the entry value.
+     */
+    function listCacheGet(key) {
+      var data = this.__data__,
+          index = assocIndexOf(data, key);
+
+      return index < 0 ? undefined : data[index][1];
+    }
+
+    /**
+     * Checks if a list cache value for `key` exists.
+     *
+     * @private
+     * @name has
+     * @memberOf ListCache
+     * @param {string} key The key of the entry to check.
+     * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
+     */
+    function listCacheHas(key) {
+      return assocIndexOf(this.__data__, key) > -1;
+    }
+
+    /**
+     * Sets the list cache `key` to `value`.
+     *
+     * @private
+     * @name set
+     * @memberOf ListCache
+     * @param {string} key The key of the value to set.
+     * @param {*} value The value to set.
+     * @returns {Object} Returns the list cache instance.
+     */
+    function listCacheSet(key, value) {
+      var data = this.__data__,
+          index = assocIndexOf(data, key);
+
+      if (index < 0) {
+        ++this.size;
+        data.push([key, value]);
+      } else {
+        data[index][1] = value;
+      }
+      return this;
+    }
+
+    // Add methods to `ListCache`.
+    ListCache.prototype.clear = listCacheClear;
+    ListCache.prototype['delete'] = listCacheDelete;
+    ListCache.prototype.get = listCacheGet;
+    ListCache.prototype.has = listCacheHas;
+    ListCache.prototype.set = listCacheSet;
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates a map cache object to store key-value pairs.
+     *
+     * @private
+     * @constructor
+     * @param {Array} [entries] The key-value pairs to cache.
+     */
+    function MapCache(entries) {
+      var index = -1,
+          length = entries == null ? 0 : entries.length;
+
+      this.clear();
+      while (++index < length) {
+        var entry = entries[index];
+        this.set(entry[0], entry[1]);
+      }
+    }
+
+    /**
+     * Removes all key-value entries from the map.
+     *
+     * @private
+     * @name clear
+     * @memberOf MapCache
+     */
+    function mapCacheClear() {
+      this.size = 0;
+      this.__data__ = {
+        'hash': new Hash,
+        'map': new (Map || ListCache),
+        'string': new Hash
+      };
+    }
+
+    /**
+     * Removes `key` and its value from the map.
+     *
+     * @private
+     * @name delete
+     * @memberOf MapCache
+     * @param {string} key The key of the value to remove.
+     * @returns {boolean} Returns `true` if the entry was removed, else `false`.
+     */
+    function mapCacheDelete(key) {
+      var result = getMapData(this, key)['delete'](key);
+      this.size -= result ? 1 : 0;
+      return result;
+    }
+
+    /**
+     * Gets the map value for `key`.
+     *
+     * @private
+     * @name get
+     * @memberOf MapCache
+     * @param {string} key The key of the value to get.
+     * @returns {*} Returns the entry value.
+     */
+    function mapCacheGet(key) {
+      return getMapData(this, key).get(key);
+    }
+
+    /**
+     * Checks if a map value for `key` exists.
+     *
+     * @private
+     * @name has
+     * @memberOf MapCache
+     * @param {string} key The key of the entry to check.
+     * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
+     */
+    function mapCacheHas(key) {
+      return getMapData(this, key).has(key);
+    }
+
+    /**
+     * Sets the map `key` to `value`.
+     *
+     * @private
+     * @name set
+     * @memberOf MapCache
+     * @param {string} key The key of the value to set.
+     * @param {*} value The value to set.
+     * @returns {Object} Returns the map cache instance.
+     */
+    function mapCacheSet(key, value) {
+      var data = getMapData(this, key),
+          size = data.size;
+
+      data.set(key, value);
+      this.size += data.size == size ? 0 : 1;
+      return this;
+    }
+
+    // Add methods to `MapCache`.
+    MapCache.prototype.clear = mapCacheClear;
+    MapCache.prototype['delete'] = mapCacheDelete;
+    MapCache.prototype.get = mapCacheGet;
+    MapCache.prototype.has = mapCacheHas;
+    MapCache.prototype.set = mapCacheSet;
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     *
+     * Creates an array cache object to store unique values.
+     *
+     * @private
+     * @constructor
+     * @param {Array} [values] The values to cache.
+     */
+    function SetCache(values) {
+      var index = -1,
+          length = values == null ? 0 : values.length;
+
+      this.__data__ = new MapCache;
+      while (++index < length) {
+        this.add(values[index]);
+      }
+    }
+
+    /**
+     * Adds `value` to the array cache.
+     *
+     * @private
+     * @name add
+     * @memberOf SetCache
+     * @alias push
+     * @param {*} value The value to cache.
+     * @returns {Object} Returns the cache instance.
+     */
+    function setCacheAdd(value) {
+      this.__data__.set(value, HASH_UNDEFINED);
+      return this;
+    }
+
+    /**
+     * Checks if `value` is in the array cache.
+     *
+     * @private
+     * @name has
+     * @memberOf SetCache
+     * @param {*} value The value to search for.
+     * @returns {number} Returns `true` if `value` is found, else `false`.
+     */
+    function setCacheHas(value) {
+      return this.__data__.has(value);
+    }
+
+    // Add methods to `SetCache`.
+    SetCache.prototype.add = SetCache.prototype.push = setCacheAdd;
+    SetCache.prototype.has = setCacheHas;
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates a stack cache object to store key-value pairs.
+     *
+     * @private
+     * @constructor
+     * @param {Array} [entries] The key-value pairs to cache.
+     */
+    function Stack(entries) {
+      var data = this.__data__ = new ListCache(entries);
+      this.size = data.size;
+    }
+
+    /**
+     * Removes all key-value entries from the stack.
+     *
+     * @private
+     * @name clear
+     * @memberOf Stack
+     */
+    function stackClear() {
+      this.__data__ = new ListCache;
+      this.size = 0;
+    }
+
+    /**
+     * Removes `key` and its value from the stack.
+     *
+     * @private
+     * @name delete
+     * @memberOf Stack
+     * @param {string} key The key of the value to remove.
+     * @returns {boolean} Returns `true` if the entry was removed, else `false`.
+     */
+    function stackDelete(key) {
+      var data = this.__data__,
+          result = data['delete'](key);
+
+      this.size = data.size;
+      return result;
+    }
+
+    /**
+     * Gets the stack value for `key`.
+     *
+     * @private
+     * @name get
+     * @memberOf Stack
+     * @param {string} key The key of the value to get.
+     * @returns {*} Returns the entry value.
+     */
+    function stackGet(key) {
+      return this.__data__.get(key);
+    }
+
+    /**
+     * Checks if a stack value for `key` exists.
+     *
+     * @private
+     * @name has
+     * @memberOf Stack
+     * @param {string} key The key of the entry to check.
+     * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
+     */
+    function stackHas(key) {
+      return this.__data__.has(key);
+    }
+
+    /**
+     * Sets the stack `key` to `value`.
+     *
+     * @private
+     * @name set
+     * @memberOf Stack
+     * @param {string} key The key of the value to set.
+     * @param {*} value The value to set.
+     * @returns {Object} Returns the stack cache instance.
+     */
+    function stackSet(key, value) {
+      var data = this.__data__;
+      if (data instanceof ListCache) {
+        var pairs = data.__data__;
+        if (!Map || (pairs.length < LARGE_ARRAY_SIZE - 1)) {
+          pairs.push([key, value]);
+          this.size = ++data.size;
+          return this;
         }
+        data = this.__data__ = new MapCache(pairs);
       }
-      // inspect [[Class]]
-      var isObj = isObject(value);
-      if (isObj) {
-        var className = toString.call(value);
-        if (!cloneableClasses[className] || (!support.nodeClass && isNode(value))) {
-          return value;
+      data.set(key, value);
+      this.size = data.size;
+      return this;
+    }
+
+    // Add methods to `Stack`.
+    Stack.prototype.clear = stackClear;
+    Stack.prototype['delete'] = stackDelete;
+    Stack.prototype.get = stackGet;
+    Stack.prototype.has = stackHas;
+    Stack.prototype.set = stackSet;
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates an array of the enumerable property names of the array-like `value`.
+     *
+     * @private
+     * @param {*} value The value to query.
+     * @param {boolean} inherited Specify returning inherited property names.
+     * @returns {Array} Returns the array of property names.
+     */
+    function arrayLikeKeys(value, inherited) {
+      var isArr = isArray(value),
+          isArg = !isArr && isArguments(value),
+          isBuff = !isArr && !isArg && isBuffer(value),
+          isType = !isArr && !isArg && !isBuff && isTypedArray(value),
+          skipIndexes = isArr || isArg || isBuff || isType,
+          result = skipIndexes ? baseTimes(value.length, String) : [],
+          length = result.length;
+
+      for (var key in value) {
+        if ((inherited || hasOwnProperty.call(value, key)) &&
+            !(skipIndexes && (
+               // Safari 9 has enumerable `arguments.length` in strict mode.
+               key == 'length' ||
+               // Node.js 0.10 has enumerable non-index properties on buffers.
+               (isBuff && (key == 'offset' || key == 'parent')) ||
+               // PhantomJS 2 has enumerable non-index properties on typed arrays.
+               (isType && (key == 'buffer' || key == 'byteLength' || key == 'byteOffset')) ||
+               // Skip index properties.
+               isIndex(key, length)
+            ))) {
+          result.push(key);
         }
-        var ctor = ctorByClass[className];
-        switch (className) {
-          case boolClass:
-          case dateClass:
-            return new ctor(+value);
-
-          case numberClass:
-          case stringClass:
-            return new ctor(value);
-
-          case regexpClass:
-            result = ctor(value.source, reFlags.exec(value));
-            result.lastIndex = value.lastIndex;
-            return result;
+      }
+      return result;
+    }
+
+    /**
+     * A specialized version of `_.sample` for arrays.
+     *
+     * @private
+     * @param {Array} array The array to sample.
+     * @returns {*} Returns the random element.
+     */
+    function arraySample(array) {
+      var length = array.length;
+      return length ? array[baseRandom(0, length - 1)] : undefined;
+    }
+
+    /**
+     * A specialized version of `_.sampleSize` for arrays.
+     *
+     * @private
+     * @param {Array} array The array to sample.
+     * @param {number} n The number of elements to sample.
+     * @returns {Array} Returns the random elements.
+     */
+    function arraySampleSize(array, n) {
+      return shuffleSelf(copyArray(array), baseClamp(n, 0, array.length));
+    }
+
+    /**
+     * A specialized version of `_.shuffle` for arrays.
+     *
+     * @private
+     * @param {Array} array The array to shuffle.
+     * @returns {Array} Returns the new shuffled array.
+     */
+    function arrayShuffle(array) {
+      return shuffleSelf(copyArray(array));
+    }
+
+    /**
+     * This function is like `assignValue` except that it doesn't assign
+     * `undefined` values.
+     *
+     * @private
+     * @param {Object} object The object to modify.
+     * @param {string} key The key of the property to assign.
+     * @param {*} value The value to assign.
+     */
+    function assignMergeValue(object, key, value) {
+      if ((value !== undefined && !eq(object[key], value)) ||
+          (value === undefined && !(key in object))) {
+        baseAssignValue(object, key, value);
+      }
+    }
+
+    /**
+     * Assigns `value` to `key` of `object` if the existing value is not equivalent
+     * using [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
+     * for equality comparisons.
+     *
+     * @private
+     * @param {Object} object The object to modify.
+     * @param {string} key The key of the property to assign.
+     * @param {*} value The value to assign.
+     */
+    function assignValue(object, key, value) {
+      var objValue = object[key];
+      if (!(hasOwnProperty.call(object, key) && eq(objValue, value)) ||
+          (value === undefined && !(key in object))) {
+        baseAssignValue(object, key, value);
+      }
+    }
+
+    /**
+     * Gets the index at which the `key` is found in `array` of key-value pairs.
+     *
+     * @private
+     * @param {Array} array The array to inspect.
+     * @param {*} key The key to search for.
+     * @returns {number} Returns the index of the matched value, else `-1`.
+     */
+    function assocIndexOf(array, key) {
+      var length = array.length;
+      while (length--) {
+        if (eq(array[length][0], key)) {
+          return length;
         }
+      }
+      return -1;
+    }
+
+    /**
+     * Aggregates elements of `collection` on `accumulator` with keys transformed
+     * by `iteratee` and values set by `setter`.
+     *
+     * @private
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function} setter The function to set `accumulator` values.
+     * @param {Function} iteratee The iteratee to transform keys.
+     * @param {Object} accumulator The initial aggregated object.
+     * @returns {Function} Returns `accumulator`.
+     */
+    function baseAggregator(collection, setter, iteratee, accumulator) {
+      baseEach(collection, function(value, key, collection) {
+        setter(accumulator, value, iteratee(value), collection);
+      });
+      return accumulator;
+    }
+
+    /**
+     * The base implementation of `_.assign` without support for multiple sources
+     * or `customizer` functions.
+     *
+     * @private
+     * @param {Object} object The destination object.
+     * @param {Object} source The source object.
+     * @returns {Object} Returns `object`.
+     */
+    function baseAssign(object, source) {
+      return object && copyObject(source, keys(source), object);
+    }
+
+    /**
+     * The base implementation of `_.assignIn` without support for multiple sources
+     * or `customizer` functions.
+     *
+     * @private
+     * @param {Object} object The destination object.
+     * @param {Object} source The source object.
+     * @returns {Object} Returns `object`.
+     */
+    function baseAssignIn(object, source) {
+      return object && copyObject(source, keysIn(source), object);
+    }
+
+    /**
+     * The base implementation of `assignValue` and `assignMergeValue` without
+     * value checks.
+     *
+     * @private
+     * @param {Object} object The object to modify.
+     * @param {string} key The key of the property to assign.
+     * @param {*} value The value to assign.
+     */
+    function baseAssignValue(object, key, value) {
+      if (key == '__proto__' && defineProperty) {
+        defineProperty(object, key, {
+          'configurable': true,
+          'enumerable': true,
+          'value': value,
+          'writable': true
+        });
       } else {
-        return value;
+        object[key] = value;
       }
-      var isArr = isArray(value);
-      if (isDeep) {
-        // check for circular references and return corresponding clone
-        var initedStack = !stackA;
-        stackA || (stackA = getArray());
-        stackB || (stackB = getArray());
+    }
 
-        var length = stackA.length;
-        while (length--) {
-          if (stackA[length] == value) {
-            return stackB[length];
-          }
+    /**
+     * The base implementation of `_.at` without support for individual paths.
+     *
+     * @private
+     * @param {Object} object The object to iterate over.
+     * @param {string[]} paths The property paths to pick.
+     * @returns {Array} Returns the picked elements.
+     */
+    function baseAt(object, paths) {
+      var index = -1,
+          length = paths.length,
+          result = Array(length),
+          skip = object == null;
+
+      while (++index < length) {
+        result[index] = skip ? undefined : get(object, paths[index]);
+      }
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.clamp` which doesn't coerce arguments.
+     *
+     * @private
+     * @param {number} number The number to clamp.
+     * @param {number} [lower] The lower bound.
+     * @param {number} upper The upper bound.
+     * @returns {number} Returns the clamped number.
+     */
+    function baseClamp(number, lower, upper) {
+      if (number === number) {
+        if (upper !== undefined) {
+          number = number <= upper ? number : upper;
+        }
+        if (lower !== undefined) {
+          number = number >= lower ? number : lower;
         }
-        result = isArr ? ctor(value.length) : {};
       }
-      else {
-        result = isArr ? slice(value) : assign({}, value);
+      return number;
+    }
+
+    /**
+     * The base implementation of `_.clone` and `_.cloneDeep` which tracks
+     * traversed objects.
+     *
+     * @private
+     * @param {*} value The value to clone.
+     * @param {boolean} bitmask The bitmask flags.
+     *  1 - Deep clone
+     *  2 - Flatten inherited properties
+     *  4 - Clone symbols
+     * @param {Function} [customizer] The function to customize cloning.
+     * @param {string} [key] The key of `value`.
+     * @param {Object} [object] The parent object of `value`.
+     * @param {Object} [stack] Tracks traversed objects and their clone counterparts.
+     * @returns {*} Returns the cloned value.
+     */
+    function baseClone(value, bitmask, customizer, key, object, stack) {
+      var result,
+          isDeep = bitmask & CLONE_DEEP_FLAG,
+          isFlat = bitmask & CLONE_FLAT_FLAG,
+          isFull = bitmask & CLONE_SYMBOLS_FLAG;
+
+      if (customizer) {
+        result = object ? customizer(value, key, object, stack) : customizer(value);
+      }
+      if (result !== undefined) {
+        return result;
       }
-      // add array properties assigned by `RegExp#exec`
+      if (!isObject(value)) {
+        return value;
+      }
+      var isArr = isArray(value);
       if (isArr) {
-        if (hasOwnProperty.call(value, 'index')) {
-          result.index = value.index;
+        result = initCloneArray(value);
+        if (!isDeep) {
+          return copyArray(value, result);
         }
-        if (hasOwnProperty.call(value, 'input')) {
-          result.input = value.input;
+      } else {
+        var tag = getTag(value),
+            isFunc = tag == funcTag || tag == genTag;
+
+        if (isBuffer(value)) {
+          return cloneBuffer(value, isDeep);
+        }
+        if (tag == objectTag || tag == argsTag || (isFunc && !object)) {
+          result = (isFlat || isFunc) ? {} : initCloneObject(value);
+          if (!isDeep) {
+            return isFlat
+              ? copySymbolsIn(value, baseAssignIn(result, value))
+              : copySymbols(value, baseAssign(result, value));
+          }
+        } else {
+          if (!cloneableTags[tag]) {
+            return object ? value : {};
+          }
+          result = initCloneByTag(value, tag, isDeep);
         }
       }
-      // exit for shallow clone
-      if (!isDeep) {
-        return result;
+      // Check for circular references and return its corresponding clone.
+      stack || (stack = new Stack);
+      var stacked = stack.get(value);
+      if (stacked) {
+        return stacked;
       }
-      // add the source value to the stack of traversed objects
-      // and associate it with its clone
-      stackA.push(value);
-      stackB.push(result);
-
-      // recursively populate clone (susceptible to call stack limits)
-      (isArr ? baseEach : forOwn)(value, function(objValue, key) {
-        result[key] = baseClone(objValue, isDeep, callback, stackA, stackB);
-      });
+      stack.set(value, result);
 
-      if (initedStack) {
-        releaseArray(stackA);
-        releaseArray(stackB);
+      if (isSet(value)) {
+        value.forEach(function(subValue) {
+          result.add(baseClone(subValue, bitmask, customizer, subValue, value, stack));
+        });
+      } else if (isMap(value)) {
+        value.forEach(function(subValue, key) {
+          result.set(key, baseClone(subValue, bitmask, customizer, key, value, stack));
+        });
       }
+
+      var keysFunc = isFull
+        ? (isFlat ? getAllKeysIn : getAllKeys)
+        : (isFlat ? keysIn : keys);
+
+      var props = isArr ? undefined : keysFunc(value);
+      arrayEach(props || value, function(subValue, key) {
+        if (props) {
+          key = subValue;
+          subValue = value[key];
+        }
+        // Recursively populate clone (susceptible to call stack limits).
+        assignValue(result, key, baseClone(subValue, bitmask, customizer, key, value, stack));
+      });
       return result;
     }
 
     /**
-     * The base implementation of `_.create` without support for assigning
-     * properties to the created object.
+     * The base implementation of `_.conforms` which doesn't clone `source`.
      *
      * @private
-     * @param {Object} prototype The object to inherit from.
-     * @returns {Object} Returns the new object.
+     * @param {Object} source The object of property predicates to conform to.
+     * @returns {Function} Returns the new spec function.
      */
-    function baseCreate(prototype, properties) {
-      return isObject(prototype) ? nativeCreate(prototype) : {};
+    function baseConforms(source) {
+      var props = keys(source);
+      return function(object) {
+        return baseConformsTo(object, source, props);
+      };
     }
-    // fallback for browsers without `Object.create`
-    if (!nativeCreate) {
-      baseCreate = (function() {
-        function Object() {}
-        return function(prototype) {
-          if (isObject(prototype)) {
-            Object.prototype = prototype;
-            var result = new Object;
-            Object.prototype = null;
-          }
-          return result || context.Object();
-        };
-      }());
+
+    /**
+     * The base implementation of `_.conformsTo` which accepts `props` to check.
+     *
+     * @private
+     * @param {Object} object The object to inspect.
+     * @param {Object} source The object of property predicates to conform to.
+     * @returns {boolean} Returns `true` if `object` conforms, else `false`.
+     */
+    function baseConformsTo(object, source, props) {
+      var length = props.length;
+      if (object == null) {
+        return !length;
+      }
+      object = Object(object);
+      while (length--) {
+        var key = props[length],
+            predicate = source[key],
+            value = object[key];
+
+        if ((value === undefined && !(key in object)) || !predicate(value)) {
+          return false;
+        }
+      }
+      return true;
     }
 
     /**
-     * The base implementation of `_.createCallback` without support for creating
-     * "_.pluck" or "_.where" style callbacks.
+     * The base implementation of `_.delay` and `_.defer` which accepts `args`
+     * to provide to `func`.
      *
      * @private
-     * @param {*} [func=identity] The value to convert to a callback.
-     * @param {*} [thisArg] The `this` binding of the created callback.
-     * @param {number} [argCount] The number of arguments the callback accepts.
-     * @returns {Function} Returns a callback function.
+     * @param {Function} func The function to delay.
+     * @param {number} wait The number of milliseconds to delay invocation.
+     * @param {Array} args The arguments to provide to `func`.
+     * @returns {number|Object} Returns the timer id or timeout object.
      */
-    function baseCreateCallback(func, thisArg, argCount) {
+    function baseDelay(func, wait, args) {
       if (typeof func != 'function') {
-        return identity;
+        throw new TypeError(FUNC_ERROR_TEXT);
       }
-      // exit early for no `thisArg` or already bound by `Function#bind`
-      if (typeof thisArg == 'undefined' || !('prototype' in func)) {
-        return func;
+      return setTimeout(function() { func.apply(undefined, args); }, wait);
+    }
+
+    /**
+     * The base implementation of methods like `_.difference` without support
+     * for excluding multiple arrays or iteratee shorthands.
+     *
+     * @private
+     * @param {Array} array The array to inspect.
+     * @param {Array} values The values to exclude.
+     * @param {Function} [iteratee] The iteratee invoked per element.
+     * @param {Function} [comparator] The comparator invoked per element.
+     * @returns {Array} Returns the new array of filtered values.
+     */
+    function baseDifference(array, values, iteratee, comparator) {
+      var index = -1,
+          includes = arrayIncludes,
+          isCommon = true,
+          length = array.length,
+          result = [],
+          valuesLength = values.length;
+
+      if (!length) {
+        return result;
       }
-      var bindData = func.__bindData__;
-      if (typeof bindData == 'undefined') {
-        if (support.funcNames) {
-          bindData = !func.name;
-        }
-        bindData = bindData || !support.funcDecomp;
-        if (!bindData) {
-          var source = fnToString.call(func);
-          if (!support.funcNames) {
-            bindData = !reFuncName.test(source);
-          }
-          if (!bindData) {
-            // checks if `func` references the `this` keyword and stores the result
-            bindData = reThis.test(source);
-            setBindData(func, bindData);
-          }
-        }
+      if (iteratee) {
+        values = arrayMap(values, baseUnary(iteratee));
       }
-      // exit early if there are no `this` references or `func` is bound
-      if (bindData === false || (bindData !== true && bindData[1] & 1)) {
-        return func;
+      if (comparator) {
+        includes = arrayIncludesWith;
+        isCommon = false;
+      }
+      else if (values.length >= LARGE_ARRAY_SIZE) {
+        includes = cacheHas;
+        isCommon = false;
+        values = new SetCache(values);
       }
-      switch (argCount) {
-        case 1: return function(value) {
-          return func.call(thisArg, value);
-        };
-        case 2: return function(a, b) {
-          return func.call(thisArg, a, b);
-        };
-        case 3: return function(value, index, collection) {
-          return func.call(thisArg, value, index, collection);
-        };
-        case 4: return function(accumulator, value, index, collection) {
-          return func.call(thisArg, accumulator, value, index, collection);
-        };
+      outer:
+      while (++index < length) {
+        var value = array[index],
+            computed = iteratee == null ? value : iteratee(value);
+
+        value = (comparator || value !== 0) ? value : 0;
+        if (isCommon && computed === computed) {
+          var valuesIndex = valuesLength;
+          while (valuesIndex--) {
+            if (values[valuesIndex] === computed) {
+              continue outer;
+            }
+          }
+          result.push(value);
+        }
+        else if (!includes(values, computed, comparator)) {
+          result.push(value);
+        }
       }
-      return bind(func, thisArg);
+      return result;
     }
 
     /**
-     * The base implementation of `createWrapper` that creates the wrapper and
-     * sets its meta data.
+     * The base implementation of `_.forEach` without support for iteratee shorthands.
      *
      * @private
-     * @param {Array} bindData The bind data array.
-     * @returns {Function} Returns the new function.
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {Array|Object} Returns `collection`.
      */
-    function baseCreateWrapper(bindData) {
-      var func = bindData[0],
-          bitmask = bindData[1],
-          partialArgs = bindData[2],
-          partialRightArgs = bindData[3],
-          thisArg = bindData[4],
-          arity = bindData[5];
-
-      var isBind = bitmask & 1,
-          isBindKey = bitmask & 2,
-          isCurry = bitmask & 4,
-          isCurryBound = bitmask & 8,
-          key = func;
-
-      function bound() {
-        var thisBinding = isBind ? thisArg : this;
-        if (partialArgs) {
-          var args = slice(partialArgs);
-          push.apply(args, arguments);
-        }
-        if (partialRightArgs || isCurry) {
-          args || (args = slice(arguments));
-          if (partialRightArgs) {
-            push.apply(args, partialRightArgs);
-          }
-          if (isCurry && args.length < arity) {
-            bitmask |= 16 & ~32;
-            return baseCreateWrapper([func, (isCurryBound ? bitmask : bitmask & ~3), args, null, thisArg, arity]);
-          }
-        }
-        args || (args = arguments);
-        if (isBindKey) {
-          func = thisBinding[key];
-        }
-        if (this instanceof bound) {
-          thisBinding = baseCreate(func.prototype);
-          var result = func.apply(thisBinding, args);
-          return isObject(result) ? result : thisBinding;
-        }
-        return func.apply(thisBinding, args);
-      }
-      setBindData(bound, bindData);
-      return bound;
+    var baseEach = createBaseEach(baseForOwn);
+
+    /**
+     * The base implementation of `_.forEachRight` without support for iteratee shorthands.
+     *
+     * @private
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {Array|Object} Returns `collection`.
+     */
+    var baseEachRight = createBaseEach(baseForOwnRight, true);
+
+    /**
+     * The base implementation of `_.every` without support for iteratee shorthands.
+     *
+     * @private
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function} predicate The function invoked per iteration.
+     * @returns {boolean} Returns `true` if all elements pass the predicate check,
+     *  else `false`
+     */
+    function baseEvery(collection, predicate) {
+      var result = true;
+      baseEach(collection, function(value, index, collection) {
+        result = !!predicate(value, index, collection);
+        return result;
+      });
+      return result;
     }
 
     /**
-     * The base implementation of `_.difference` that accepts a single array
-     * of values to exclude.
+     * The base implementation of methods like `_.max` and `_.min` which accepts a
+     * `comparator` to determine the extremum value.
      *
      * @private
-     * @param {Array} array The array to process.
-     * @param {Array} [values] The array of values to exclude.
-     * @returns {Array} Returns a new array of filtered values.
+     * @param {Array} array The array to iterate over.
+     * @param {Function} iteratee The iteratee invoked per iteration.
+     * @param {Function} comparator The comparator used to compare values.
+     * @returns {*} Returns the extremum value.
      */
-    function baseDifference(array, values) {
+    function baseExtremum(array, iteratee, comparator) {
       var index = -1,
-          indexOf = getIndexOf(),
-          length = array ? array.length : 0,
-          isLarge = length >= largeArraySize && indexOf === baseIndexOf,
-          result = [];
+          length = array.length;
 
-      if (isLarge) {
-        var cache = createCache(values);
-        if (cache) {
-          indexOf = cacheIndexOf;
-          values = cache;
-        } else {
-          isLarge = false;
-        }
-      }
       while (++index < length) {
-        var value = array[index];
-        if (indexOf(values, value) < 0) {
-          result.push(value);
+        var value = array[index],
+            current = iteratee(value);
+
+        if (current != null && (computed === undefined
+              ? (current === current && !isSymbol(current))
+              : comparator(current, computed)
+            )) {
+          var computed = current,
+              result = value;
         }
       }
-      if (isLarge) {
-        releaseObject(values);
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.fill` without an iteratee call guard.
+     *
+     * @private
+     * @param {Array} array The array to fill.
+     * @param {*} value The value to fill `array` with.
+     * @param {number} [start=0] The start position.
+     * @param {number} [end=array.length] The end position.
+     * @returns {Array} Returns `array`.
+     */
+    function baseFill(array, value, start, end) {
+      var length = array.length;
+
+      start = toInteger(start);
+      if (start < 0) {
+        start = -start > length ? 0 : (length + start);
+      }
+      end = (end === undefined || end > length) ? length : toInteger(end);
+      if (end < 0) {
+        end += length;
+      }
+      end = start > end ? 0 : toLength(end);
+      while (start < end) {
+        array[start++] = value;
       }
+      return array;
+    }
+
+    /**
+     * The base implementation of `_.filter` without support for iteratee shorthands.
+     *
+     * @private
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function} predicate The function invoked per iteration.
+     * @returns {Array} Returns the new filtered array.
+     */
+    function baseFilter(collection, predicate) {
+      var result = [];
+      baseEach(collection, function(value, index, collection) {
+        if (predicate(value, index, collection)) {
+          result.push(value);
+        }
+      });
       return result;
     }
 
     /**
-     * The base implementation of `_.flatten` without support for callback
-     * shorthands or `thisArg` binding.
+     * The base implementation of `_.flatten` with support for restricting flattening.
      *
      * @private
      * @param {Array} array The array to flatten.
-     * @param {boolean} [isShallow=false] A flag to restrict flattening to a single level.
-     * @param {boolean} [isStrict=false] A flag to restrict flattening to arrays and `arguments` objects.
-     * @param {number} [fromIndex=0] The index to start from.
-     * @returns {Array} Returns a new flattened array.
-     */
-    function baseFlatten(array, isShallow, isStrict, fromIndex) {
-      var index = (fromIndex || 0) - 1,
-          length = array ? array.length : 0,
-          result = [];
+     * @param {number} depth The maximum recursion depth.
+     * @param {boolean} [predicate=isFlattenable] The function invoked per iteration.
+     * @param {boolean} [isStrict] Restrict to values that pass `predicate` checks.
+     * @param {Array} [result=[]] The initial result value.
+     * @returns {Array} Returns the new flattened array.
+     */
+    function baseFlatten(array, depth, predicate, isStrict, result) {
+      var index = -1,
+          length = array.length;
+
+      predicate || (predicate = isFlattenable);
+      result || (result = []);
 
       while (++index < length) {
         var value = array[index];
-
-        if (value && typeof value == 'object' && typeof value.length == 'number'
-            && (isArray(value) || isArguments(value))) {
-          // recursively flatten arrays (susceptible to call stack limits)
-          if (!isShallow) {
-            value = baseFlatten(value, isShallow, isStrict);
-          }
-          var valIndex = -1,
-              valLength = value.length,
-              resIndex = result.length;
-
-          result.length += valLength;
-          while (++valIndex < valLength) {
-            result[resIndex++] = value[valIndex];
+        if (depth > 0 && predicate(value)) {
+          if (depth > 1) {
+            // Recursively flatten arrays (susceptible to call stack limits).
+            baseFlatten(value, depth - 1, predicate, isStrict, result);
+          } else {
+            arrayPush(result, value);
           }
         } else if (!isStrict) {
+          result[result.length] = value;
+        }
+      }
+      return result;
+    }
+
+    /**
+     * The base implementation of `baseForOwn` which iterates over `object`
+     * properties returned by `keysFunc` and invokes `iteratee` for each property.
+     * Iteratee functions may exit iteration early by explicitly returning `false`.
+     *
+     * @private
+     * @param {Object} object The object to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @param {Function} keysFunc The function to get the keys of `object`.
+     * @returns {Object} Returns `object`.
+     */
+    var baseFor = createBaseFor();
+
+    /**
+     * This function is like `baseFor` except that it iterates over properties
+     * in the opposite order.
+     *
+     * @private
+     * @param {Object} object The object to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @param {Function} keysFunc The function to get the keys of `object`.
+     * @returns {Object} Returns `object`.
+     */
+    var baseForRight = createBaseFor(true);
+
+    /**
+     * The base implementation of `_.forOwn` without support for iteratee shorthands.
+     *
+     * @private
+     * @param {Object} object The object to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {Object} Returns `object`.
+     */
+    function baseForOwn(object, iteratee) {
+      return object && baseFor(object, iteratee, keys);
+    }
+
+    /**
+     * The base implementation of `_.forOwnRight` without support for iteratee shorthands.
+     *
+     * @private
+     * @param {Object} object The object to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {Object} Returns `object`.
+     */
+    function baseForOwnRight(object, iteratee) {
+      return object && baseForRight(object, iteratee, keys);
+    }
+
+    /**
+     * The base implementation of `_.functions` which creates an array of
+     * `object` function property names filtered from `props`.
+     *
+     * @private
+     * @param {Object} object The object to inspect.
+     * @param {Array} props The property names to filter.
+     * @returns {Array} Returns the function names.
+     */
+    function baseFunctions(object, props) {
+      return arrayFilter(props, function(key) {
+        return isFunction(object[key]);
+      });
+    }
+
+    /**
+     * The base implementation of `_.get` without support for default values.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @param {Array|string} path The path of the property to get.
+     * @returns {*} Returns the resolved value.
+     */
+    function baseGet(object, path) {
+      path = castPath(path, object);
+
+      var index = 0,
+          length = path.length;
+
+      while (object != null && index < length) {
+        object = object[toKey(path[index++])];
+      }
+      return (index && index == length) ? object : undefined;
+    }
+
+    /**
+     * The base implementation of `getAllKeys` and `getAllKeysIn` which uses
+     * `keysFunc` and `symbolsFunc` to get the enumerable property names and
+     * symbols of `object`.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @param {Function} keysFunc The function to get the keys of `object`.
+     * @param {Function} symbolsFunc The function to get the symbols of `object`.
+     * @returns {Array} Returns the array of property names and symbols.
+     */
+    function baseGetAllKeys(object, keysFunc, symbolsFunc) {
+      var result = keysFunc(object);
+      return isArray(object) ? result : arrayPush(result, symbolsFunc(object));
+    }
+
+    /**
+     * The base implementation of `getTag` without fallbacks for buggy environments.
+     *
+     * @private
+     * @param {*} value The value to query.
+     * @returns {string} Returns the `toStringTag`.
+     */
+    function baseGetTag(value) {
+      if (value == null) {
+        return value === undefined ? undefinedTag : nullTag;
+      }
+      return (symToStringTag && symToStringTag in Object(value))
+        ? getRawTag(value)
+        : objectToString(value);
+    }
+
+    /**
+     * The base implementation of `_.gt` which doesn't coerce arguments.
+     *
+     * @private
+     * @param {*} value The value to compare.
+     * @param {*} other The other value to compare.
+     * @returns {boolean} Returns `true` if `value` is greater than `other`,
+     *  else `false`.
+     */
+    function baseGt(value, other) {
+      return value > other;
+    }
+
+    /**
+     * The base implementation of `_.has` without support for deep paths.
+     *
+     * @private
+     * @param {Object} [object] The object to query.
+     * @param {Array|string} key The key to check.
+     * @returns {boolean} Returns `true` if `key` exists, else `false`.
+     */
+    function baseHas(object, key) {
+      return object != null && hasOwnProperty.call(object, key);
+    }
+
+    /**
+     * The base implementation of `_.hasIn` without support for deep paths.
+     *
+     * @private
+     * @param {Object} [object] The object to query.
+     * @param {Array|string} key The key to check.
+     * @returns {boolean} Returns `true` if `key` exists, else `false`.
+     */
+    function baseHasIn(object, key) {
+      return object != null && key in Object(object);
+    }
+
+    /**
+     * The base implementation of `_.inRange` which doesn't coerce arguments.
+     *
+     * @private
+     * @param {number} number The number to check.
+     * @param {number} start The start of the range.
+     * @param {number} end The end of the range.
+     * @returns {boolean} Returns `true` if `number` is in the range, else `false`.
+     */
+    function baseInRange(number, start, end) {
+      return number >= nativeMin(start, end) && number < nativeMax(start, end);
+    }
+
+    /**
+     * The base implementation of methods like `_.intersection`, without support
+     * for iteratee shorthands, that accepts an array of arrays to inspect.
+     *
+     * @private
+     * @param {Array} arrays The arrays to inspect.
+     * @param {Function} [iteratee] The iteratee invoked per element.
+     * @param {Function} [comparator] The comparator invoked per element.
+     * @returns {Array} Returns the new array of shared values.
+     */
+    function baseIntersection(arrays, iteratee, comparator) {
+      var includes = comparator ? arrayIncludesWith : arrayIncludes,
+          length = arrays[0].length,
+          othLength = arrays.length,
+          othIndex = othLength,
+          caches = Array(othLength),
+          maxLength = Infinity,
+          result = [];
+
+      while (othIndex--) {
+        var array = arrays[othIndex];
+        if (othIndex && iteratee) {
+          array = arrayMap(array, baseUnary(iteratee));
+        }
+        maxLength = nativeMin(array.length, maxLength);
+        caches[othIndex] = !comparator && (iteratee || (length >= 120 && array.length >= 120))
+          ? new SetCache(othIndex && array)
+          : undefined;
+      }
+      array = arrays[0];
+
+      var index = -1,
+          seen = caches[0];
+
+      outer:
+      while (++index < length && result.length < maxLength) {
+        var value = array[index],
+            computed = iteratee ? iteratee(value) : value;
+
+        value = (comparator || value !== 0) ? value : 0;
+        if (!(seen
+              ? cacheHas(seen, computed)
+              : includes(result, computed, comparator)
+            )) {
+          othIndex = othLength;
+          while (--othIndex) {
+            var cache = caches[othIndex];
+            if (!(cache
+                  ? cacheHas(cache, computed)
+                  : includes(arrays[othIndex], computed, comparator))
+                ) {
+              continue outer;
+            }
+          }
+          if (seen) {
+            seen.push(computed);
+          }
           result.push(value);
         }
       }
@@ -1330,5096 +3225,10910 @@
     }
 
     /**
-     * The base implementation of `_.isEqual`, without support for `thisArg` binding,
-     * that allows partial "_.where" style comparisons.
+     * The base implementation of `_.invert` and `_.invertBy` which inverts
+     * `object` with values transformed by `iteratee` and set by `setter`.
+     *
+     * @private
+     * @param {Object} object The object to iterate over.
+     * @param {Function} setter The function to set `accumulator` values.
+     * @param {Function} iteratee The iteratee to transform values.
+     * @param {Object} accumulator The initial inverted object.
+     * @returns {Function} Returns `accumulator`.
+     */
+    function baseInverter(object, setter, iteratee, accumulator) {
+      baseForOwn(object, function(value, key, object) {
+        setter(accumulator, iteratee(value), key, object);
+      });
+      return accumulator;
+    }
+
+    /**
+     * The base implementation of `_.invoke` without support for individual
+     * method arguments.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @param {Array|string} path The path of the method to invoke.
+     * @param {Array} args The arguments to invoke the method with.
+     * @returns {*} Returns the result of the invoked method.
+     */
+    function baseInvoke(object, path, args) {
+      path = castPath(path, object);
+      object = parent(object, path);
+      var func = object == null ? object : object[toKey(last(path))];
+      return func == null ? undefined : apply(func, object, args);
+    }
+
+    /**
+     * The base implementation of `_.isArguments`.
+     *
+     * @private
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is an `arguments` object,
+     */
+    function baseIsArguments(value) {
+      return isObjectLike(value) && baseGetTag(value) == argsTag;
+    }
+
+    /**
+     * The base implementation of `_.isArrayBuffer` without Node.js optimizations.
+     *
+     * @private
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is an array buffer, else `false`.
+     */
+    function baseIsArrayBuffer(value) {
+      return isObjectLike(value) && baseGetTag(value) == arrayBufferTag;
+    }
+
+    /**
+     * The base implementation of `_.isDate` without Node.js optimizations.
      *
      * @private
-     * @param {*} a The value to compare.
-     * @param {*} b The other value to compare.
-     * @param {Function} [callback] The function to customize comparing values.
-     * @param {Function} [isWhere=false] A flag to indicate performing partial comparisons.
-     * @param {Array} [stackA=[]] Tracks traversed `a` objects.
-     * @param {Array} [stackB=[]] Tracks traversed `b` objects.
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a date object, else `false`.
+     */
+    function baseIsDate(value) {
+      return isObjectLike(value) && baseGetTag(value) == dateTag;
+    }
+
+    /**
+     * The base implementation of `_.isEqual` which supports partial comparisons
+     * and tracks traversed objects.
+     *
+     * @private
+     * @param {*} value The value to compare.
+     * @param {*} other The other value to compare.
+     * @param {boolean} bitmask The bitmask flags.
+     *  1 - Unordered comparison
+     *  2 - Partial comparison
+     * @param {Function} [customizer] The function to customize comparisons.
+     * @param {Object} [stack] Tracks traversed `value` and `other` objects.
      * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
      */
-    function baseIsEqual(a, b, callback, isWhere, stackA, stackB) {
-      // used to indicate that when comparing objects, `a` has at least the properties of `b`
-      if (callback) {
-        var result = callback(a, b);
-        if (typeof result != 'undefined') {
-          return !!result;
-        }
-      }
-      // exit early for identical values
-      if (a === b) {
-        // treat `+0` vs. `-0` as not equal
-        return a !== 0 || (1 / a == 1 / b);
-      }
-      var type = typeof a,
-          otherType = typeof b;
-
-      // exit early for unlike primitive values
-      if (a === a &&
-          !(a && objectTypes[type]) &&
-          !(b && objectTypes[otherType])) {
-        return false;
+    function baseIsEqual(value, other, bitmask, customizer, stack) {
+      if (value === other) {
+        return true;
+      }
+      if (value == null || other == null || (!isObjectLike(value) && !isObjectLike(other))) {
+        return value !== value && other !== other;
       }
-      // exit early for `null` and `undefined` avoiding ES3's Function#call behavior
-      // http://es5.github.io/#x15.3.4.4
-      if (a == null || b == null) {
-        return a === b;
-      }
-      // compare [[Class]] names
-      var className = toString.call(a),
-          otherClass = toString.call(b);
+      return baseIsEqualDeep(value, other, bitmask, customizer, baseIsEqual, stack);
+    }
+
+    /**
+     * A specialized version of `baseIsEqual` for arrays and objects which performs
+     * deep comparisons and tracks traversed objects enabling objects with circular
+     * references to be compared.
+     *
+     * @private
+     * @param {Object} object The object to compare.
+     * @param {Object} other The other object to compare.
+     * @param {number} bitmask The bitmask flags. See `baseIsEqual` for more details.
+     * @param {Function} customizer The function to customize comparisons.
+     * @param {Function} equalFunc The function to determine equivalents of values.
+     * @param {Object} [stack] Tracks traversed `object` and `other` objects.
+     * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
+     */
+    function baseIsEqualDeep(object, other, bitmask, customizer, equalFunc, stack) {
+      var objIsArr = isArray(object),
+          othIsArr = isArray(other),
+          objTag = objIsArr ? arrayTag : getTag(object),
+          othTag = othIsArr ? arrayTag : getTag(other);
+
+      objTag = objTag == argsTag ? objectTag : objTag;
+      othTag = othTag == argsTag ? objectTag : othTag;
+
+      var objIsObj = objTag == objectTag,
+          othIsObj = othTag == objectTag,
+          isSameTag = objTag == othTag;
 
-      if (className == argsClass) {
-        className = objectClass;
+      if (isSameTag && isBuffer(object)) {
+        if (!isBuffer(other)) {
+          return false;
+        }
+        objIsArr = true;
+        objIsObj = false;
+      }
+      if (isSameTag && !objIsObj) {
+        stack || (stack = new Stack);
+        return (objIsArr || isTypedArray(object))
+          ? equalArrays(object, other, bitmask, customizer, equalFunc, stack)
+          : equalByTag(object, other, objTag, bitmask, customizer, equalFunc, stack);
       }
-      if (otherClass == argsClass) {
-        otherClass = objectClass;
+      if (!(bitmask & COMPARE_PARTIAL_FLAG)) {
+        var objIsWrapped = objIsObj && hasOwnProperty.call(object, '__wrapped__'),
+            othIsWrapped = othIsObj && hasOwnProperty.call(other, '__wrapped__');
+
+        if (objIsWrapped || othIsWrapped) {
+          var objUnwrapped = objIsWrapped ? object.value() : object,
+              othUnwrapped = othIsWrapped ? other.value() : other;
+
+          stack || (stack = new Stack);
+          return equalFunc(objUnwrapped, othUnwrapped, bitmask, customizer, stack);
+        }
       }
-      if (className != otherClass) {
+      if (!isSameTag) {
         return false;
       }
-      switch (className) {
-        case boolClass:
-        case dateClass:
-          // coerce dates and booleans to numbers, dates to milliseconds and booleans
-          // to `1` or `0` treating invalid dates coerced to `NaN` as not equal
-          return +a == +b;
-
-        case numberClass:
-          // treat `NaN` vs. `NaN` as equal
-          return (a != +a)
-            ? b != +b
-            // but treat `+0` vs. `-0` as not equal
-            : (a == 0 ? (1 / a == 1 / b) : a == +b);
-
-        case regexpClass:
-        case stringClass:
-          // coerce regexes to strings (http://es5.github.io/#x15.10.6.4)
-          // treat string primitives and their corresponding object instances as equal
-          return a == String(b);
-      }
-      var isArr = className == arrayClass;
-      if (!isArr) {
-        // unwrap any `lodash` wrapped values
-        var aWrapped = hasOwnProperty.call(a, '__wrapped__'),
-            bWrapped = hasOwnProperty.call(b, '__wrapped__');
+      stack || (stack = new Stack);
+      return equalObjects(object, other, bitmask, customizer, equalFunc, stack);
+    }
 
-        if (aWrapped || bWrapped) {
-          return baseIsEqual(aWrapped ? a.__wrapped__ : a, bWrapped ? b.__wrapped__ : b, callback, isWhere, stackA, stackB);
-        }
-        // exit for functions and DOM nodes
-        if (className != objectClass || (!support.nodeClass && (isNode(a) || isNode(b)))) {
-          return false;
-        }
-        // in older versions of Opera, `arguments` objects have `Array` constructors
-        var ctorA = !support.argsObject && isArguments(a) ? Object : a.constructor,
-            ctorB = !support.argsObject && isArguments(b) ? Object : b.constructor;
-
-        // non `Object` object instances with different constructors are not equal
-        if (ctorA != ctorB &&
-              !(isFunction(ctorA) && ctorA instanceof ctorA && isFunction(ctorB) && ctorB instanceof ctorB) &&
-              ('constructor' in a && 'constructor' in b)
+    /**
+     * The base implementation of `_.isMap` without Node.js optimizations.
+     *
+     * @private
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a map, else `false`.
+     */
+    function baseIsMap(value) {
+      return isObjectLike(value) && getTag(value) == mapTag;
+    }
+
+    /**
+     * The base implementation of `_.isMatch` without support for iteratee shorthands.
+     *
+     * @private
+     * @param {Object} object The object to inspect.
+     * @param {Object} source The object of property values to match.
+     * @param {Array} matchData The property names, values, and compare flags to match.
+     * @param {Function} [customizer] The function to customize comparisons.
+     * @returns {boolean} Returns `true` if `object` is a match, else `false`.
+     */
+    function baseIsMatch(object, source, matchData, customizer) {
+      var index = matchData.length,
+          length = index,
+          noCustomizer = !customizer;
+
+      if (object == null) {
+        return !length;
+      }
+      object = Object(object);
+      while (index--) {
+        var data = matchData[index];
+        if ((noCustomizer && data[2])
+              ? data[1] !== object[data[0]]
+              : !(data[0] in object)
             ) {
           return false;
         }
       }
-      // assume cyclic structures are equal
-      // the algorithm for detecting cyclic structures is adapted from ES 5.1
-      // section 15.12.3, abstract operation `JO` (http://es5.github.io/#x15.12.3)
-      var initedStack = !stackA;
-      stackA || (stackA = getArray());
-      stackB || (stackB = getArray());
+      while (++index < length) {
+        data = matchData[index];
+        var key = data[0],
+            objValue = object[key],
+            srcValue = data[1];
 
-      var length = stackA.length;
-      while (length--) {
-        if (stackA[length] == a) {
-          return stackB[length] == b;
+        if (noCustomizer && data[2]) {
+          if (objValue === undefined && !(key in object)) {
+            return false;
+          }
+        } else {
+          var stack = new Stack;
+          if (customizer) {
+            var result = customizer(objValue, srcValue, key, object, source, stack);
+          }
+          if (!(result === undefined
+                ? baseIsEqual(srcValue, objValue, COMPARE_PARTIAL_FLAG | COMPARE_UNORDERED_FLAG, customizer, stack)
+                : result
+              )) {
+            return false;
+          }
         }
       }
-      var size = 0;
-      result = true;
+      return true;
+    }
+
+    /**
+     * The base implementation of `_.isNative` without bad shim checks.
+     *
+     * @private
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a native function,
+     *  else `false`.
+     */
+    function baseIsNative(value) {
+      if (!isObject(value) || isMasked(value)) {
+        return false;
+      }
+      var pattern = isFunction(value) ? reIsNative : reIsHostCtor;
+      return pattern.test(toSource(value));
+    }
 
-      // add `a` and `b` to the stack of traversed objects
-      stackA.push(a);
-      stackB.push(b);
+    /**
+     * The base implementation of `_.isRegExp` without Node.js optimizations.
+     *
+     * @private
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a regexp, else `false`.
+     */
+    function baseIsRegExp(value) {
+      return isObjectLike(value) && baseGetTag(value) == regexpTag;
+    }
 
-      // recursively compare objects and arrays (susceptible to call stack limits)
-      if (isArr) {
-        // compare lengths to determine if a deep comparison is necessary
-        length = a.length;
-        size = b.length;
-        result = size == length;
-
-        if (result || isWhere) {
-          // deep compare the contents, ignoring non-numeric properties
-          while (size--) {
-            var index = length,
-                value = b[size];
-
-            if (isWhere) {
-              while (index--) {
-                if ((result = baseIsEqual(a[index], value, callback, isWhere, stackA, stackB))) {
-                  break;
-                }
-              }
-            } else if (!(result = baseIsEqual(a[size], value, callback, isWhere, stackA, stackB))) {
-              break;
-            }
-          }
-        }
+    /**
+     * The base implementation of `_.isSet` without Node.js optimizations.
+     *
+     * @private
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a set, else `false`.
+     */
+    function baseIsSet(value) {
+      return isObjectLike(value) && getTag(value) == setTag;
+    }
+
+    /**
+     * The base implementation of `_.isTypedArray` without Node.js optimizations.
+     *
+     * @private
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a typed array, else `false`.
+     */
+    function baseIsTypedArray(value) {
+      return isObjectLike(value) &&
+        isLength(value.length) && !!typedArrayTags[baseGetTag(value)];
+    }
+
+    /**
+     * The base implementation of `_.iteratee`.
+     *
+     * @private
+     * @param {*} [value=_.identity] The value to convert to an iteratee.
+     * @returns {Function} Returns the iteratee.
+     */
+    function baseIteratee(value) {
+      // Don't store the `typeof` result in a variable to avoid a JIT bug in Safari 9.
+      // See https://bugs.webkit.org/show_bug.cgi?id=156034 for more details.
+      if (typeof value == 'function') {
+        return value;
       }
-      else {
-        // deep compare objects using `forIn`, instead of `forOwn`, to avoid `Object.keys`
-        // which, in this case, is more costly
-        forIn(b, function(value, key, b) {
-          if (hasOwnProperty.call(b, key)) {
-            // count the number of properties.
-            size++;
-            // deep compare each property value.
-            return (result = hasOwnProperty.call(a, key) && baseIsEqual(a[key], value, callback, isWhere, stackA, stackB));
-          }
-        });
+      if (value == null) {
+        return identity;
+      }
+      if (typeof value == 'object') {
+        return isArray(value)
+          ? baseMatchesProperty(value[0], value[1])
+          : baseMatches(value);
+      }
+      return property(value);
+    }
 
-        if (result && !isWhere) {
-          // ensure both objects have the same number of properties
-          forIn(a, function(value, key, a) {
-            if (hasOwnProperty.call(a, key)) {
-              // `size` will be `-1` if `a` has more properties than `b`
-              return (result = --size > -1);
-            }
-          });
+    /**
+     * The base implementation of `_.keys` which doesn't treat sparse arrays as dense.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the array of property names.
+     */
+    function baseKeys(object) {
+      if (!isPrototype(object)) {
+        return nativeKeys(object);
+      }
+      var result = [];
+      for (var key in Object(object)) {
+        if (hasOwnProperty.call(object, key) && key != 'constructor') {
+          result.push(key);
         }
       }
-      stackA.pop();
-      stackB.pop();
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.keysIn` which doesn't treat sparse arrays as dense.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the array of property names.
+     */
+    function baseKeysIn(object) {
+      if (!isObject(object)) {
+        return nativeKeysIn(object);
+      }
+      var isProto = isPrototype(object),
+          result = [];
 
-      if (initedStack) {
-        releaseArray(stackA);
-        releaseArray(stackB);
+      for (var key in object) {
+        if (!(key == 'constructor' && (isProto || !hasOwnProperty.call(object, key)))) {
+          result.push(key);
+        }
       }
       return result;
     }
 
     /**
-     * The base implementation of `_.merge` without argument juggling or support
-     * for `thisArg` binding.
+     * The base implementation of `_.lt` which doesn't coerce arguments.
+     *
+     * @private
+     * @param {*} value The value to compare.
+     * @param {*} other The other value to compare.
+     * @returns {boolean} Returns `true` if `value` is less than `other`,
+     *  else `false`.
+     */
+    function baseLt(value, other) {
+      return value < other;
+    }
+
+    /**
+     * The base implementation of `_.map` without support for iteratee shorthands.
+     *
+     * @private
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {Array} Returns the new mapped array.
+     */
+    function baseMap(collection, iteratee) {
+      var index = -1,
+          result = isArrayLike(collection) ? Array(collection.length) : [];
+
+      baseEach(collection, function(value, key, collection) {
+        result[++index] = iteratee(value, key, collection);
+      });
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.matches` which doesn't clone `source`.
+     *
+     * @private
+     * @param {Object} source The object of property values to match.
+     * @returns {Function} Returns the new spec function.
+     */
+    function baseMatches(source) {
+      var matchData = getMatchData(source);
+      if (matchData.length == 1 && matchData[0][2]) {
+        return matchesStrictComparable(matchData[0][0], matchData[0][1]);
+      }
+      return function(object) {
+        return object === source || baseIsMatch(object, source, matchData);
+      };
+    }
+
+    /**
+     * The base implementation of `_.matchesProperty` which doesn't clone `srcValue`.
+     *
+     * @private
+     * @param {string} path The path of the property to get.
+     * @param {*} srcValue The value to match.
+     * @returns {Function} Returns the new spec function.
+     */
+    function baseMatchesProperty(path, srcValue) {
+      if (isKey(path) && isStrictComparable(srcValue)) {
+        return matchesStrictComparable(toKey(path), srcValue);
+      }
+      return function(object) {
+        var objValue = get(object, path);
+        return (objValue === undefined && objValue === srcValue)
+          ? hasIn(object, path)
+          : baseIsEqual(srcValue, objValue, COMPARE_PARTIAL_FLAG | COMPARE_UNORDERED_FLAG);
+      };
+    }
+
+    /**
+     * The base implementation of `_.merge` without support for multiple sources.
      *
      * @private
      * @param {Object} object The destination object.
      * @param {Object} source The source object.
-     * @param {Function} [callback] The function to customize merging properties.
-     * @param {Array} [stackA=[]] Tracks traversed source objects.
-     * @param {Array} [stackB=[]] Associates values with source counterparts.
-     */
-    function baseMerge(object, source, callback, stackA, stackB) {
-      (isArray(source) ? forEach : forOwn)(source, function(source, key) {
-        var found,
-            isArr,
-            result = source,
-            value = object[key];
+     * @param {number} srcIndex The index of `source`.
+     * @param {Function} [customizer] The function to customize merged values.
+     * @param {Object} [stack] Tracks traversed source values and their merged
+     *  counterparts.
+     */
+    function baseMerge(object, source, srcIndex, customizer, stack) {
+      if (object === source) {
+        return;
+      }
+      baseFor(source, function(srcValue, key) {
+        stack || (stack = new Stack);
+        if (isObject(srcValue)) {
+          baseMergeDeep(object, source, key, srcIndex, baseMerge, customizer, stack);
+        }
+        else {
+          var newValue = customizer
+            ? customizer(safeGet(object, key), srcValue, (key + ''), object, source, stack)
+            : undefined;
 
-        if (source && ((isArr = isArray(source)) || isPlainObject(source))) {
-          // avoid merging previously merged cyclic sources
-          var stackLength = stackA.length;
-          while (stackLength--) {
-            if ((found = stackA[stackLength] == source)) {
-              value = stackB[stackLength];
-              break;
-            }
+          if (newValue === undefined) {
+            newValue = srcValue;
           }
-          if (!found) {
-            var isShallow;
-            if (callback) {
-              result = callback(value, source);
-              if ((isShallow = typeof result != 'undefined')) {
-                value = result;
-              }
-            }
-            if (!isShallow) {
-              value = isArr
-                ? (isArray(value) ? value : [])
-                : (isPlainObject(value) ? value : {});
-            }
-            // add `source` and associated `value` to the stack of traversed objects
-            stackA.push(source);
-            stackB.push(value);
-
-            // recursively merge objects and arrays (susceptible to call stack limits)
-            if (!isShallow) {
-              baseMerge(value, source, callback, stackA, stackB);
-            }
+          assignMergeValue(object, key, newValue);
+        }
+      }, keysIn);
+    }
+
+    /**
+     * A specialized version of `baseMerge` for arrays and objects which performs
+     * deep merges and tracks traversed objects enabling objects with circular
+     * references to be merged.
+     *
+     * @private
+     * @param {Object} object The destination object.
+     * @param {Object} source The source object.
+     * @param {string} key The key of the value to merge.
+     * @param {number} srcIndex The index of `source`.
+     * @param {Function} mergeFunc The function to merge values.
+     * @param {Function} [customizer] The function to customize assigned values.
+     * @param {Object} [stack] Tracks traversed source values and their merged
+     *  counterparts.
+     */
+    function baseMergeDeep(object, source, key, srcIndex, mergeFunc, customizer, stack) {
+      var objValue = safeGet(object, key),
+          srcValue = safeGet(source, key),
+          stacked = stack.get(srcValue);
+
+      if (stacked) {
+        assignMergeValue(object, key, stacked);
+        return;
+      }
+      var newValue = customizer
+        ? customizer(objValue, srcValue, (key + ''), object, source, stack)
+        : undefined;
+
+      var isCommon = newValue === undefined;
+
+      if (isCommon) {
+        var isArr = isArray(srcValue),
+            isBuff = !isArr && isBuffer(srcValue),
+            isTyped = !isArr && !isBuff && isTypedArray(srcValue);
+
+        newValue = srcValue;
+        if (isArr || isBuff || isTyped) {
+          if (isArray(objValue)) {
+            newValue = objValue;
+          }
+          else if (isArrayLikeObject(objValue)) {
+            newValue = copyArray(objValue);
+          }
+          else if (isBuff) {
+            isCommon = false;
+            newValue = cloneBuffer(srcValue, true);
+          }
+          else if (isTyped) {
+            isCommon = false;
+            newValue = cloneTypedArray(srcValue, true);
+          }
+          else {
+            newValue = [];
+          }
+        }
+        else if (isPlainObject(srcValue) || isArguments(srcValue)) {
+          newValue = objValue;
+          if (isArguments(objValue)) {
+            newValue = toPlainObject(objValue);
+          }
+          else if (!isObject(objValue) || isFunction(objValue)) {
+            newValue = initCloneObject(srcValue);
           }
         }
         else {
-          if (callback) {
-            result = callback(value, source);
-            if (typeof result == 'undefined') {
-              result = source;
+          isCommon = false;
+        }
+      }
+      if (isCommon) {
+        // Recursively merge objects and arrays (susceptible to call stack limits).
+        stack.set(srcValue, newValue);
+        mergeFunc(newValue, srcValue, srcIndex, customizer, stack);
+        stack['delete'](srcValue);
+      }
+      assignMergeValue(object, key, newValue);
+    }
+
+    /**
+     * The base implementation of `_.nth` which doesn't coerce arguments.
+     *
+     * @private
+     * @param {Array} array The array to query.
+     * @param {number} n The index of the element to return.
+     * @returns {*} Returns the nth element of `array`.
+     */
+    function baseNth(array, n) {
+      var length = array.length;
+      if (!length) {
+        return;
+      }
+      n += n < 0 ? length : 0;
+      return isIndex(n, length) ? array[n] : undefined;
+    }
+
+    /**
+     * The base implementation of `_.orderBy` without param guards.
+     *
+     * @private
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function[]|Object[]|string[]} iteratees The iteratees to sort by.
+     * @param {string[]} orders The sort orders of `iteratees`.
+     * @returns {Array} Returns the new sorted array.
+     */
+    function baseOrderBy(collection, iteratees, orders) {
+      if (iteratees.length) {
+        iteratees = arrayMap(iteratees, function(iteratee) {
+          if (isArray(iteratee)) {
+            return function(value) {
+              return baseGet(value, iteratee.length === 1 ? iteratee[0] : iteratee);
             }
           }
-          if (typeof result != 'undefined') {
-            value = result;
+          return iteratee;
+        });
+      } else {
+        iteratees = [identity];
+      }
+
+      var index = -1;
+      iteratees = arrayMap(iteratees, baseUnary(getIteratee()));
+
+      var result = baseMap(collection, function(value, key, collection) {
+        var criteria = arrayMap(iteratees, function(iteratee) {
+          return iteratee(value);
+        });
+        return { 'criteria': criteria, 'index': ++index, 'value': value };
+      });
+
+      return baseSortBy(result, function(object, other) {
+        return compareMultiple(object, other, orders);
+      });
+    }
+
+    /**
+     * The base implementation of `_.pick` without support for individual
+     * property identifiers.
+     *
+     * @private
+     * @param {Object} object The source object.
+     * @param {string[]} paths The property paths to pick.
+     * @returns {Object} Returns the new object.
+     */
+    function basePick(object, paths) {
+      return basePickBy(object, paths, function(value, path) {
+        return hasIn(object, path);
+      });
+    }
+
+    /**
+     * The base implementation of  `_.pickBy` without support for iteratee shorthands.
+     *
+     * @private
+     * @param {Object} object The source object.
+     * @param {string[]} paths The property paths to pick.
+     * @param {Function} predicate The function invoked per property.
+     * @returns {Object} Returns the new object.
+     */
+    function basePickBy(object, paths, predicate) {
+      var index = -1,
+          length = paths.length,
+          result = {};
+
+      while (++index < length) {
+        var path = paths[index],
+            value = baseGet(object, path);
+
+        if (predicate(value, path)) {
+          baseSet(result, castPath(path, object), value);
+        }
+      }
+      return result;
+    }
+
+    /**
+     * A specialized version of `baseProperty` which supports deep paths.
+     *
+     * @private
+     * @param {Array|string} path The path of the property to get.
+     * @returns {Function} Returns the new accessor function.
+     */
+    function basePropertyDeep(path) {
+      return function(object) {
+        return baseGet(object, path);
+      };
+    }
+
+    /**
+     * The base implementation of `_.pullAllBy` without support for iteratee
+     * shorthands.
+     *
+     * @private
+     * @param {Array} array The array to modify.
+     * @param {Array} values The values to remove.
+     * @param {Function} [iteratee] The iteratee invoked per element.
+     * @param {Function} [comparator] The comparator invoked per element.
+     * @returns {Array} Returns `array`.
+     */
+    function basePullAll(array, values, iteratee, comparator) {
+      var indexOf = comparator ? baseIndexOfWith : baseIndexOf,
+          index = -1,
+          length = values.length,
+          seen = array;
+
+      if (array === values) {
+        values = copyArray(values);
+      }
+      if (iteratee) {
+        seen = arrayMap(array, baseUnary(iteratee));
+      }
+      while (++index < length) {
+        var fromIndex = 0,
+            value = values[index],
+            computed = iteratee ? iteratee(value) : value;
+
+        while ((fromIndex = indexOf(seen, computed, fromIndex, comparator)) > -1) {
+          if (seen !== array) {
+            splice.call(seen, fromIndex, 1);
           }
+          splice.call(array, fromIndex, 1);
         }
-        object[key] = value;
+      }
+      return array;
+    }
+
+    /**
+     * The base implementation of `_.pullAt` without support for individual
+     * indexes or capturing the removed elements.
+     *
+     * @private
+     * @param {Array} array The array to modify.
+     * @param {number[]} indexes The indexes of elements to remove.
+     * @returns {Array} Returns `array`.
+     */
+    function basePullAt(array, indexes) {
+      var length = array ? indexes.length : 0,
+          lastIndex = length - 1;
+
+      while (length--) {
+        var index = indexes[length];
+        if (length == lastIndex || index !== previous) {
+          var previous = index;
+          if (isIndex(index)) {
+            splice.call(array, index, 1);
+          } else {
+            baseUnset(array, index);
+          }
+        }
+      }
+      return array;
+    }
+
+    /**
+     * The base implementation of `_.random` without support for returning
+     * floating-point numbers.
+     *
+     * @private
+     * @param {number} lower The lower bound.
+     * @param {number} upper The upper bound.
+     * @returns {number} Returns the random number.
+     */
+    function baseRandom(lower, upper) {
+      return lower + nativeFloor(nativeRandom() * (upper - lower + 1));
+    }
+
+    /**
+     * The base implementation of `_.range` and `_.rangeRight` which doesn't
+     * coerce arguments.
+     *
+     * @private
+     * @param {number} start The start of the range.
+     * @param {number} end The end of the range.
+     * @param {number} step The value to increment or decrement by.
+     * @param {boolean} [fromRight] Specify iterating from right to left.
+     * @returns {Array} Returns the range of numbers.
+     */
+    function baseRange(start, end, step, fromRight) {
+      var index = -1,
+          length = nativeMax(nativeCeil((end - start) / (step || 1)), 0),
+          result = Array(length);
+
+      while (length--) {
+        result[fromRight ? length : ++index] = start;
+        start += step;
+      }
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.repeat` which doesn't coerce arguments.
+     *
+     * @private
+     * @param {string} string The string to repeat.
+     * @param {number} n The number of times to repeat the string.
+     * @returns {string} Returns the repeated string.
+     */
+    function baseRepeat(string, n) {
+      var result = '';
+      if (!string || n < 1 || n > MAX_SAFE_INTEGER) {
+        return result;
+      }
+      // Leverage the exponentiation by squaring algorithm for a faster repeat.
+      // See https://en.wikipedia.org/wiki/Exponentiation_by_squaring for more details.
+      do {
+        if (n % 2) {
+          result += string;
+        }
+        n = nativeFloor(n / 2);
+        if (n) {
+          string += string;
+        }
+      } while (n);
+
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.rest` which doesn't validate or coerce arguments.
+     *
+     * @private
+     * @param {Function} func The function to apply a rest parameter to.
+     * @param {number} [start=func.length-1] The start position of the rest parameter.
+     * @returns {Function} Returns the new function.
+     */
+    function baseRest(func, start) {
+      return setToString(overRest(func, start, identity), func + '');
+    }
+
+    /**
+     * The base implementation of `_.sample`.
+     *
+     * @private
+     * @param {Array|Object} collection The collection to sample.
+     * @returns {*} Returns the random element.
+     */
+    function baseSample(collection) {
+      return arraySample(values(collection));
+    }
+
+    /**
+     * The base implementation of `_.sampleSize` without param guards.
+     *
+     * @private
+     * @param {Array|Object} collection The collection to sample.
+     * @param {number} n The number of elements to sample.
+     * @returns {Array} Returns the random elements.
+     */
+    function baseSampleSize(collection, n) {
+      var array = values(collection);
+      return shuffleSelf(array, baseClamp(n, 0, array.length));
+    }
+
+    /**
+     * The base implementation of `_.set`.
+     *
+     * @private
+     * @param {Object} object The object to modify.
+     * @param {Array|string} path The path of the property to set.
+     * @param {*} value The value to set.
+     * @param {Function} [customizer] The function to customize path creation.
+     * @returns {Object} Returns `object`.
+     */
+    function baseSet(object, path, value, customizer) {
+      if (!isObject(object)) {
+        return object;
+      }
+      path = castPath(path, object);
+
+      var index = -1,
+          length = path.length,
+          lastIndex = length - 1,
+          nested = object;
+
+      while (nested != null && ++index < length) {
+        var key = toKey(path[index]),
+            newValue = value;
+
+        if (key === '__proto__' || key === 'constructor' || key === 'prototype') {
+          return object;
+        }
+
+        if (index != lastIndex) {
+          var objValue = nested[key];
+          newValue = customizer ? customizer(objValue, key, nested) : undefined;
+          if (newValue === undefined) {
+            newValue = isObject(objValue)
+              ? objValue
+              : (isIndex(path[index + 1]) ? [] : {});
+          }
+        }
+        assignValue(nested, key, newValue);
+        nested = nested[key];
+      }
+      return object;
+    }
+
+    /**
+     * The base implementation of `setData` without support for hot loop shorting.
+     *
+     * @private
+     * @param {Function} func The function to associate metadata with.
+     * @param {*} data The metadata.
+     * @returns {Function} Returns `func`.
+     */
+    var baseSetData = !metaMap ? identity : function(func, data) {
+      metaMap.set(func, data);
+      return func;
+    };
+
+    /**
+     * The base implementation of `setToString` without support for hot loop shorting.
+     *
+     * @private
+     * @param {Function} func The function to modify.
+     * @param {Function} string The `toString` result.
+     * @returns {Function} Returns `func`.
+     */
+    var baseSetToString = !defineProperty ? identity : function(func, string) {
+      return defineProperty(func, 'toString', {
+        'configurable': true,
+        'enumerable': false,
+        'value': constant(string),
+        'writable': true
       });
+    };
+
+    /**
+     * The base implementation of `_.shuffle`.
+     *
+     * @private
+     * @param {Array|Object} collection The collection to shuffle.
+     * @returns {Array} Returns the new shuffled array.
+     */
+    function baseShuffle(collection) {
+      return shuffleSelf(values(collection));
     }
 
     /**
-     * The base implementation of `_.random` without argument juggling or support
-     * for returning floating-point numbers.
+     * The base implementation of `_.slice` without an iteratee call guard.
      *
      * @private
-     * @param {number} min The minimum possible value.
-     * @param {number} max The maximum possible value.
-     * @returns {number} Returns a random number.
+     * @param {Array} array The array to slice.
+     * @param {number} [start=0] The start position.
+     * @param {number} [end=array.length] The end position.
+     * @returns {Array} Returns the slice of `array`.
      */
-    function baseRandom(min, max) {
-      return min + floor(nativeRandom() * (max - min + 1));
+    function baseSlice(array, start, end) {
+      var index = -1,
+          length = array.length;
+
+      if (start < 0) {
+        start = -start > length ? 0 : (length + start);
+      }
+      end = end > length ? length : end;
+      if (end < 0) {
+        end += length;
+      }
+      length = start > end ? 0 : ((end - start) >>> 0);
+      start >>>= 0;
+
+      var result = Array(length);
+      while (++index < length) {
+        result[index] = array[index + start];
+      }
+      return result;
     }
 
     /**
-     * The base implementation of `_.uniq` without support for callback shorthands
-     * or `thisArg` binding.
+     * The base implementation of `_.some` without support for iteratee shorthands.
      *
      * @private
-     * @param {Array} array The array to process.
-     * @param {boolean} [isSorted=false] A flag to indicate that `array` is sorted.
-     * @param {Function} [callback] The function called per iteration.
-     * @returns {Array} Returns a duplicate-value-free array.
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function} predicate The function invoked per iteration.
+     * @returns {boolean} Returns `true` if any element passes the predicate check,
+     *  else `false`.
+     */
+    function baseSome(collection, predicate) {
+      var result;
+
+      baseEach(collection, function(value, index, collection) {
+        result = predicate(value, index, collection);
+        return !result;
+      });
+      return !!result;
+    }
+
+    /**
+     * The base implementation of `_.sortedIndex` and `_.sortedLastIndex` which
+     * performs a binary search of `array` to determine the index at which `value`
+     * should be inserted into `array` in order to maintain its sort order.
+     *
+     * @private
+     * @param {Array} array The sorted array to inspect.
+     * @param {*} value The value to evaluate.
+     * @param {boolean} [retHighest] Specify returning the highest qualified index.
+     * @returns {number} Returns the index at which `value` should be inserted
+     *  into `array`.
      */
-    function baseUniq(array, isSorted, callback) {
+    function baseSortedIndex(array, value, retHighest) {
+      var low = 0,
+          high = array == null ? low : array.length;
+
+      if (typeof value == 'number' && value === value && high <= HALF_MAX_ARRAY_LENGTH) {
+        while (low < high) {
+          var mid = (low + high) >>> 1,
+              computed = array[mid];
+
+          if (computed !== null && !isSymbol(computed) &&
+              (retHighest ? (computed <= value) : (computed < value))) {
+            low = mid + 1;
+          } else {
+            high = mid;
+          }
+        }
+        return high;
+      }
+      return baseSortedIndexBy(array, value, identity, retHighest);
+    }
+
+    /**
+     * The base implementation of `_.sortedIndexBy` and `_.sortedLastIndexBy`
+     * which invokes `iteratee` for `value` and each element of `array` to compute
+     * their sort ranking. The iteratee is invoked with one argument; (value).
+     *
+     * @private
+     * @param {Array} array The sorted array to inspect.
+     * @param {*} value The value to evaluate.
+     * @param {Function} iteratee The iteratee invoked per element.
+     * @param {boolean} [retHighest] Specify returning the highest qualified index.
+     * @returns {number} Returns the index at which `value` should be inserted
+     *  into `array`.
+     */
+    function baseSortedIndexBy(array, value, iteratee, retHighest) {
+      var low = 0,
+          high = array == null ? 0 : array.length;
+      if (high === 0) {
+        return 0;
+      }
+
+      value = iteratee(value);
+      var valIsNaN = value !== value,
+          valIsNull = value === null,
+          valIsSymbol = isSymbol(value),
+          valIsUndefined = value === undefined;
+
+      while (low < high) {
+        var mid = nativeFloor((low + high) / 2),
+            computed = iteratee(array[mid]),
+            othIsDefined = computed !== undefined,
+            othIsNull = computed === null,
+            othIsReflexive = computed === computed,
+            othIsSymbol = isSymbol(computed);
+
+        if (valIsNaN) {
+          var setLow = retHighest || othIsReflexive;
+        } else if (valIsUndefined) {
+          setLow = othIsReflexive && (retHighest || othIsDefined);
+        } else if (valIsNull) {
+          setLow = othIsReflexive && othIsDefined && (retHighest || !othIsNull);
+        } else if (valIsSymbol) {
+          setLow = othIsReflexive && othIsDefined && !othIsNull && (retHighest || !othIsSymbol);
+        } else if (othIsNull || othIsSymbol) {
+          setLow = false;
+        } else {
+          setLow = retHighest ? (computed <= value) : (computed < value);
+        }
+        if (setLow) {
+          low = mid + 1;
+        } else {
+          high = mid;
+        }
+      }
+      return nativeMin(high, MAX_ARRAY_INDEX);
+    }
+
+    /**
+     * The base implementation of `_.sortedUniq` and `_.sortedUniqBy` without
+     * support for iteratee shorthands.
+     *
+     * @private
+     * @param {Array} array The array to inspect.
+     * @param {Function} [iteratee] The iteratee invoked per element.
+     * @returns {Array} Returns the new duplicate free array.
+     */
+    function baseSortedUniq(array, iteratee) {
       var index = -1,
-          indexOf = getIndexOf(),
-          length = array ? array.length : 0,
+          length = array.length,
+          resIndex = 0,
           result = [];
 
-      var isLarge = !isSorted && length >= largeArraySize && indexOf === baseIndexOf,
-          seen = (callback || isLarge) ? getArray() : result;
+      while (++index < length) {
+        var value = array[index],
+            computed = iteratee ? iteratee(value) : value;
+
+        if (!index || !eq(computed, seen)) {
+          var seen = computed;
+          result[resIndex++] = value === 0 ? 0 : value;
+        }
+      }
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.toNumber` which doesn't ensure correct
+     * conversions of binary, hexadecimal, or octal string values.
+     *
+     * @private
+     * @param {*} value The value to process.
+     * @returns {number} Returns the number.
+     */
+    function baseToNumber(value) {
+      if (typeof value == 'number') {
+        return value;
+      }
+      if (isSymbol(value)) {
+        return NAN;
+      }
+      return +value;
+    }
 
-      if (isLarge) {
-        var cache = createCache(seen);
-        indexOf = cacheIndexOf;
-        seen = cache;
+    /**
+     * The base implementation of `_.toString` which doesn't convert nullish
+     * values to empty strings.
+     *
+     * @private
+     * @param {*} value The value to process.
+     * @returns {string} Returns the string.
+     */
+    function baseToString(value) {
+      // Exit early for strings to avoid a performance hit in some environments.
+      if (typeof value == 'string') {
+        return value;
+      }
+      if (isArray(value)) {
+        // Recursively convert values (susceptible to call stack limits).
+        return arrayMap(value, baseToString) + '';
+      }
+      if (isSymbol(value)) {
+        return symbolToString ? symbolToString.call(value) : '';
       }
+      var result = (value + '');
+      return (result == '0' && (1 / value) == -INFINITY) ? '-0' : result;
+    }
+
+    /**
+     * The base implementation of `_.uniqBy` without support for iteratee shorthands.
+     *
+     * @private
+     * @param {Array} array The array to inspect.
+     * @param {Function} [iteratee] The iteratee invoked per element.
+     * @param {Function} [comparator] The comparator invoked per element.
+     * @returns {Array} Returns the new duplicate free array.
+     */
+    function baseUniq(array, iteratee, comparator) {
+      var index = -1,
+          includes = arrayIncludes,
+          length = array.length,
+          isCommon = true,
+          result = [],
+          seen = result;
+
+      if (comparator) {
+        isCommon = false;
+        includes = arrayIncludesWith;
+      }
+      else if (length >= LARGE_ARRAY_SIZE) {
+        var set = iteratee ? null : createSet(array);
+        if (set) {
+          return setToArray(set);
+        }
+        isCommon = false;
+        includes = cacheHas;
+        seen = new SetCache;
+      }
+      else {
+        seen = iteratee ? [] : result;
+      }
+      outer:
       while (++index < length) {
         var value = array[index],
-            computed = callback ? callback(value, index, array) : value;
+            computed = iteratee ? iteratee(value) : value;
 
-        if (isSorted
-              ? !index || seen[seen.length - 1] !== computed
-              : indexOf(seen, computed) < 0
-            ) {
-          if (callback || isLarge) {
+        value = (comparator || value !== 0) ? value : 0;
+        if (isCommon && computed === computed) {
+          var seenIndex = seen.length;
+          while (seenIndex--) {
+            if (seen[seenIndex] === computed) {
+              continue outer;
+            }
+          }
+          if (iteratee) {
+            seen.push(computed);
+          }
+          result.push(value);
+        }
+        else if (!includes(seen, computed, comparator)) {
+          if (seen !== result) {
             seen.push(computed);
           }
           result.push(value);
         }
       }
-      if (isLarge) {
-        releaseArray(seen.array);
-        releaseObject(seen);
-      } else if (callback) {
-        releaseArray(seen);
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.unset`.
+     *
+     * @private
+     * @param {Object} object The object to modify.
+     * @param {Array|string} path The property path to unset.
+     * @returns {boolean} Returns `true` if the property is deleted, else `false`.
+     */
+    function baseUnset(object, path) {
+      path = castPath(path, object);
+      object = parent(object, path);
+      return object == null || delete object[toKey(last(path))];
+    }
+
+    /**
+     * The base implementation of `_.update`.
+     *
+     * @private
+     * @param {Object} object The object to modify.
+     * @param {Array|string} path The path of the property to update.
+     * @param {Function} updater The function to produce the updated value.
+     * @param {Function} [customizer] The function to customize path creation.
+     * @returns {Object} Returns `object`.
+     */
+    function baseUpdate(object, path, updater, customizer) {
+      return baseSet(object, path, updater(baseGet(object, path)), customizer);
+    }
+
+    /**
+     * The base implementation of methods like `_.dropWhile` and `_.takeWhile`
+     * without support for iteratee shorthands.
+     *
+     * @private
+     * @param {Array} array The array to query.
+     * @param {Function} predicate The function invoked per iteration.
+     * @param {boolean} [isDrop] Specify dropping elements instead of taking them.
+     * @param {boolean} [fromRight] Specify iterating from right to left.
+     * @returns {Array} Returns the slice of `array`.
+     */
+    function baseWhile(array, predicate, isDrop, fromRight) {
+      var length = array.length,
+          index = fromRight ? length : -1;
+
+      while ((fromRight ? index-- : ++index < length) &&
+        predicate(array[index], index, array)) {}
+
+      return isDrop
+        ? baseSlice(array, (fromRight ? 0 : index), (fromRight ? index + 1 : length))
+        : baseSlice(array, (fromRight ? index + 1 : 0), (fromRight ? length : index));
+    }
+
+    /**
+     * The base implementation of `wrapperValue` which returns the result of
+     * performing a sequence of actions on the unwrapped `value`, where each
+     * successive action is supplied the return value of the previous.
+     *
+     * @private
+     * @param {*} value The unwrapped value.
+     * @param {Array} actions Actions to perform to resolve the unwrapped value.
+     * @returns {*} Returns the resolved value.
+     */
+    function baseWrapperValue(value, actions) {
+      var result = value;
+      if (result instanceof LazyWrapper) {
+        result = result.value();
+      }
+      return arrayReduce(actions, function(result, action) {
+        return action.func.apply(action.thisArg, arrayPush([result], action.args));
+      }, result);
+    }
+
+    /**
+     * The base implementation of methods like `_.xor`, without support for
+     * iteratee shorthands, that accepts an array of arrays to inspect.
+     *
+     * @private
+     * @param {Array} arrays The arrays to inspect.
+     * @param {Function} [iteratee] The iteratee invoked per element.
+     * @param {Function} [comparator] The comparator invoked per element.
+     * @returns {Array} Returns the new array of values.
+     */
+    function baseXor(arrays, iteratee, comparator) {
+      var length = arrays.length;
+      if (length < 2) {
+        return length ? baseUniq(arrays[0]) : [];
+      }
+      var index = -1,
+          result = Array(length);
+
+      while (++index < length) {
+        var array = arrays[index],
+            othIndex = -1;
+
+        while (++othIndex < length) {
+          if (othIndex != index) {
+            result[index] = baseDifference(result[index] || array, arrays[othIndex], iteratee, comparator);
+          }
+        }
+      }
+      return baseUniq(baseFlatten(result, 1), iteratee, comparator);
+    }
+
+    /**
+     * This base implementation of `_.zipObject` which assigns values using `assignFunc`.
+     *
+     * @private
+     * @param {Array} props The property identifiers.
+     * @param {Array} values The property values.
+     * @param {Function} assignFunc The function to assign values.
+     * @returns {Object} Returns the new object.
+     */
+    function baseZipObject(props, values, assignFunc) {
+      var index = -1,
+          length = props.length,
+          valsLength = values.length,
+          result = {};
+
+      while (++index < length) {
+        var value = index < valsLength ? values[index] : undefined;
+        assignFunc(result, props[index], value);
+      }
+      return result;
+    }
+
+    /**
+     * Casts `value` to an empty array if it's not an array like object.
+     *
+     * @private
+     * @param {*} value The value to inspect.
+     * @returns {Array|Object} Returns the cast array-like object.
+     */
+    function castArrayLikeObject(value) {
+      return isArrayLikeObject(value) ? value : [];
+    }
+
+    /**
+     * Casts `value` to `identity` if it's not a function.
+     *
+     * @private
+     * @param {*} value The value to inspect.
+     * @returns {Function} Returns cast function.
+     */
+    function castFunction(value) {
+      return typeof value == 'function' ? value : identity;
+    }
+
+    /**
+     * Casts `value` to a path array if it's not one.
+     *
+     * @private
+     * @param {*} value The value to inspect.
+     * @param {Object} [object] The object to query keys on.
+     * @returns {Array} Returns the cast property path array.
+     */
+    function castPath(value, object) {
+      if (isArray(value)) {
+        return value;
+      }
+      return isKey(value, object) ? [value] : stringToPath(toString(value));
+    }
+
+    /**
+     * A `baseRest` alias which can be replaced with `identity` by module
+     * replacement plugins.
+     *
+     * @private
+     * @type {Function}
+     * @param {Function} func The function to apply a rest parameter to.
+     * @returns {Function} Returns the new function.
+     */
+    var castRest = baseRest;
+
+    /**
+     * Casts `array` to a slice if it's needed.
+     *
+     * @private
+     * @param {Array} array The array to inspect.
+     * @param {number} start The start position.
+     * @param {number} [end=array.length] The end position.
+     * @returns {Array} Returns the cast slice.
+     */
+    function castSlice(array, start, end) {
+      var length = array.length;
+      end = end === undefined ? length : end;
+      return (!start && end >= length) ? array : baseSlice(array, start, end);
+    }
+
+    /**
+     * A simple wrapper around the global [`clearTimeout`](https://mdn.io/clearTimeout).
+     *
+     * @private
+     * @param {number|Object} id The timer id or timeout object of the timer to clear.
+     */
+    var clearTimeout = ctxClearTimeout || function(id) {
+      return root.clearTimeout(id);
+    };
+
+    /**
+     * Creates a clone of  `buffer`.
+     *
+     * @private
+     * @param {Buffer} buffer The buffer to clone.
+     * @param {boolean} [isDeep] Specify a deep clone.
+     * @returns {Buffer} Returns the cloned buffer.
+     */
+    function cloneBuffer(buffer, isDeep) {
+      if (isDeep) {
+        return buffer.slice();
+      }
+      var length = buffer.length,
+          result = allocUnsafe ? allocUnsafe(length) : new buffer.constructor(length);
+
+      buffer.copy(result);
+      return result;
+    }
+
+    /**
+     * Creates a clone of `arrayBuffer`.
+     *
+     * @private
+     * @param {ArrayBuffer} arrayBuffer The array buffer to clone.
+     * @returns {ArrayBuffer} Returns the cloned array buffer.
+     */
+    function cloneArrayBuffer(arrayBuffer) {
+      var result = new arrayBuffer.constructor(arrayBuffer.byteLength);
+      new Uint8Array(result).set(new Uint8Array(arrayBuffer));
+      return result;
+    }
+
+    /**
+     * Creates a clone of `dataView`.
+     *
+     * @private
+     * @param {Object} dataView The data view to clone.
+     * @param {boolean} [isDeep] Specify a deep clone.
+     * @returns {Object} Returns the cloned data view.
+     */
+    function cloneDataView(dataView, isDeep) {
+      var buffer = isDeep ? cloneArrayBuffer(dataView.buffer) : dataView.buffer;
+      return new dataView.constructor(buffer, dataView.byteOffset, dataView.byteLength);
+    }
+
+    /**
+     * Creates a clone of `regexp`.
+     *
+     * @private
+     * @param {Object} regexp The regexp to clone.
+     * @returns {Object} Returns the cloned regexp.
+     */
+    function cloneRegExp(regexp) {
+      var result = new regexp.constructor(regexp.source, reFlags.exec(regexp));
+      result.lastIndex = regexp.lastIndex;
+      return result;
+    }
+
+    /**
+     * Creates a clone of the `symbol` object.
+     *
+     * @private
+     * @param {Object} symbol The symbol object to clone.
+     * @returns {Object} Returns the cloned symbol object.
+     */
+    function cloneSymbol(symbol) {
+      return symbolValueOf ? Object(symbolValueOf.call(symbol)) : {};
+    }
+
+    /**
+     * Creates a clone of `typedArray`.
+     *
+     * @private
+     * @param {Object} typedArray The typed array to clone.
+     * @param {boolean} [isDeep] Specify a deep clone.
+     * @returns {Object} Returns the cloned typed array.
+     */
+    function cloneTypedArray(typedArray, isDeep) {
+      var buffer = isDeep ? cloneArrayBuffer(typedArray.buffer) : typedArray.buffer;
+      return new typedArray.constructor(buffer, typedArray.byteOffset, typedArray.length);
+    }
+
+    /**
+     * Compares values to sort them in ascending order.
+     *
+     * @private
+     * @param {*} value The value to compare.
+     * @param {*} other The other value to compare.
+     * @returns {number} Returns the sort order indicator for `value`.
+     */
+    function compareAscending(value, other) {
+      if (value !== other) {
+        var valIsDefined = value !== undefined,
+            valIsNull = value === null,
+            valIsReflexive = value === value,
+            valIsSymbol = isSymbol(value);
+
+        var othIsDefined = other !== undefined,
+            othIsNull = other === null,
+            othIsReflexive = other === other,
+            othIsSymbol = isSymbol(other);
+
+        if ((!othIsNull && !othIsSymbol && !valIsSymbol && value > other) ||
+            (valIsSymbol && othIsDefined && othIsReflexive && !othIsNull && !othIsSymbol) ||
+            (valIsNull && othIsDefined && othIsReflexive) ||
+            (!valIsDefined && othIsReflexive) ||
+            !valIsReflexive) {
+          return 1;
+        }
+        if ((!valIsNull && !valIsSymbol && !othIsSymbol && value < other) ||
+            (othIsSymbol && valIsDefined && valIsReflexive && !valIsNull && !valIsSymbol) ||
+            (othIsNull && valIsDefined && valIsReflexive) ||
+            (!othIsDefined && valIsReflexive) ||
+            !othIsReflexive) {
+          return -1;
+        }
+      }
+      return 0;
+    }
+
+    /**
+     * Used by `_.orderBy` to compare multiple properties of a value to another
+     * and stable sort them.
+     *
+     * If `orders` is unspecified, all values are sorted in ascending order. Otherwise,
+     * specify an order of "desc" for descending or "asc" for ascending sort order
+     * of corresponding values.
+     *
+     * @private
+     * @param {Object} object The object to compare.
+     * @param {Object} other The other object to compare.
+     * @param {boolean[]|string[]} orders The order to sort by for each property.
+     * @returns {number} Returns the sort order indicator for `object`.
+     */
+    function compareMultiple(object, other, orders) {
+      var index = -1,
+          objCriteria = object.criteria,
+          othCriteria = other.criteria,
+          length = objCriteria.length,
+          ordersLength = orders.length;
+
+      while (++index < length) {
+        var result = compareAscending(objCriteria[index], othCriteria[index]);
+        if (result) {
+          if (index >= ordersLength) {
+            return result;
+          }
+          var order = orders[index];
+          return result * (order == 'desc' ? -1 : 1);
+        }
+      }
+      // Fixes an `Array#sort` bug in the JS engine embedded in Adobe applications
+      // that causes it, under certain circumstances, to provide the same value for
+      // `object` and `other`. See https://github.com/jashkenas/underscore/pull/1247
+      // for more details.
+      //
+      // This also ensures a stable sort in V8 and other engines.
+      // See https://bugs.chromium.org/p/v8/issues/detail?id=90 for more details.
+      return object.index - other.index;
+    }
+
+    /**
+     * Creates an array that is the composition of partially applied arguments,
+     * placeholders, and provided arguments into a single array of arguments.
+     *
+     * @private
+     * @param {Array} args The provided arguments.
+     * @param {Array} partials The arguments to prepend to those provided.
+     * @param {Array} holders The `partials` placeholder indexes.
+     * @params {boolean} [isCurried] Specify composing for a curried function.
+     * @returns {Array} Returns the new array of composed arguments.
+     */
+    function composeArgs(args, partials, holders, isCurried) {
+      var argsIndex = -1,
+          argsLength = args.length,
+          holdersLength = holders.length,
+          leftIndex = -1,
+          leftLength = partials.length,
+          rangeLength = nativeMax(argsLength - holdersLength, 0),
+          result = Array(leftLength + rangeLength),
+          isUncurried = !isCurried;
+
+      while (++leftIndex < leftLength) {
+        result[leftIndex] = partials[leftIndex];
+      }
+      while (++argsIndex < holdersLength) {
+        if (isUncurried || argsIndex < argsLength) {
+          result[holders[argsIndex]] = args[argsIndex];
+        }
+      }
+      while (rangeLength--) {
+        result[leftIndex++] = args[argsIndex++];
+      }
+      return result;
+    }
+
+    /**
+     * This function is like `composeArgs` except that the arguments composition
+     * is tailored for `_.partialRight`.
+     *
+     * @private
+     * @param {Array} args The provided arguments.
+     * @param {Array} partials The arguments to append to those provided.
+     * @param {Array} holders The `partials` placeholder indexes.
+     * @params {boolean} [isCurried] Specify composing for a curried function.
+     * @returns {Array} Returns the new array of composed arguments.
+     */
+    function composeArgsRight(args, partials, holders, isCurried) {
+      var argsIndex = -1,
+          argsLength = args.length,
+          holdersIndex = -1,
+          holdersLength = holders.length,
+          rightIndex = -1,
+          rightLength = partials.length,
+          rangeLength = nativeMax(argsLength - holdersLength, 0),
+          result = Array(rangeLength + rightLength),
+          isUncurried = !isCurried;
+
+      while (++argsIndex < rangeLength) {
+        result[argsIndex] = args[argsIndex];
+      }
+      var offset = argsIndex;
+      while (++rightIndex < rightLength) {
+        result[offset + rightIndex] = partials[rightIndex];
+      }
+      while (++holdersIndex < holdersLength) {
+        if (isUncurried || argsIndex < argsLength) {
+          result[offset + holders[holdersIndex]] = args[argsIndex++];
+        }
       }
       return result;
     }
 
     /**
-     * Creates a function that aggregates a collection, creating an object composed
-     * of keys generated from the results of running each element of the collection
-     * through a callback. The given `setter` function sets the keys and values
-     * of the composed object.
+     * Copies the values of `source` to `array`.
      *
      * @private
-     * @param {Function} setter The setter function.
+     * @param {Array} source The array to copy values from.
+     * @param {Array} [array=[]] The array to copy values to.
+     * @returns {Array} Returns `array`.
+     */
+    function copyArray(source, array) {
+      var index = -1,
+          length = source.length;
+
+      array || (array = Array(length));
+      while (++index < length) {
+        array[index] = source[index];
+      }
+      return array;
+    }
+
+    /**
+     * Copies properties of `source` to `object`.
+     *
+     * @private
+     * @param {Object} source The object to copy properties from.
+     * @param {Array} props The property identifiers to copy.
+     * @param {Object} [object={}] The object to copy properties to.
+     * @param {Function} [customizer] The function to customize copied values.
+     * @returns {Object} Returns `object`.
+     */
+    function copyObject(source, props, object, customizer) {
+      var isNew = !object;
+      object || (object = {});
+
+      var index = -1,
+          length = props.length;
+
+      while (++index < length) {
+        var key = props[index];
+
+        var newValue = customizer
+          ? customizer(object[key], source[key], key, object, source)
+          : undefined;
+
+        if (newValue === undefined) {
+          newValue = source[key];
+        }
+        if (isNew) {
+          baseAssignValue(object, key, newValue);
+        } else {
+          assignValue(object, key, newValue);
+        }
+      }
+      return object;
+    }
+
+    /**
+     * Copies own symbols of `source` to `object`.
+     *
+     * @private
+     * @param {Object} source The object to copy symbols from.
+     * @param {Object} [object={}] The object to copy symbols to.
+     * @returns {Object} Returns `object`.
+     */
+    function copySymbols(source, object) {
+      return copyObject(source, getSymbols(source), object);
+    }
+
+    /**
+     * Copies own and inherited symbols of `source` to `object`.
+     *
+     * @private
+     * @param {Object} source The object to copy symbols from.
+     * @param {Object} [object={}] The object to copy symbols to.
+     * @returns {Object} Returns `object`.
+     */
+    function copySymbolsIn(source, object) {
+      return copyObject(source, getSymbolsIn(source), object);
+    }
+
+    /**
+     * Creates a function like `_.groupBy`.
+     *
+     * @private
+     * @param {Function} setter The function to set accumulator values.
+     * @param {Function} [initializer] The accumulator object initializer.
      * @returns {Function} Returns the new aggregator function.
      */
-    function createAggregator(setter) {
-      return function(collection, callback, thisArg) {
-        var result = {};
-        callback = lodash.createCallback(callback, thisArg, 3);
-
-        if (isArray(collection)) {
-          var index = -1,
-              length = collection.length;
+    function createAggregator(setter, initializer) {
+      return function(collection, iteratee) {
+        var func = isArray(collection) ? arrayAggregator : baseAggregator,
+            accumulator = initializer ? initializer() : {};
+
+        return func(collection, setter, getIteratee(iteratee, 2), accumulator);
+      };
+    }
+
+    /**
+     * Creates a function like `_.assign`.
+     *
+     * @private
+     * @param {Function} assigner The function to assign values.
+     * @returns {Function} Returns the new assigner function.
+     */
+    function createAssigner(assigner) {
+      return baseRest(function(object, sources) {
+        var index = -1,
+            length = sources.length,
+            customizer = length > 1 ? sources[length - 1] : undefined,
+            guard = length > 2 ? sources[2] : undefined;
+
+        customizer = (assigner.length > 3 && typeof customizer == 'function')
+          ? (length--, customizer)
+          : undefined;
+
+        if (guard && isIterateeCall(sources[0], sources[1], guard)) {
+          customizer = length < 3 ? undefined : customizer;
+          length = 1;
+        }
+        object = Object(object);
+        while (++index < length) {
+          var source = sources[index];
+          if (source) {
+            assigner(object, source, index, customizer);
+          }
+        }
+        return object;
+      });
+    }
+
+    /**
+     * Creates a `baseEach` or `baseEachRight` function.
+     *
+     * @private
+     * @param {Function} eachFunc The function to iterate over a collection.
+     * @param {boolean} [fromRight] Specify iterating from right to left.
+     * @returns {Function} Returns the new base function.
+     */
+    function createBaseEach(eachFunc, fromRight) {
+      return function(collection, iteratee) {
+        if (collection == null) {
+          return collection;
+        }
+        if (!isArrayLike(collection)) {
+          return eachFunc(collection, iteratee);
+        }
+        var length = collection.length,
+            index = fromRight ? length : -1,
+            iterable = Object(collection);
+
+        while ((fromRight ? index-- : ++index < length)) {
+          if (iteratee(iterable[index], index, iterable) === false) {
+            break;
+          }
+        }
+        return collection;
+      };
+    }
+
+    /**
+     * Creates a base function for methods like `_.forIn` and `_.forOwn`.
+     *
+     * @private
+     * @param {boolean} [fromRight] Specify iterating from right to left.
+     * @returns {Function} Returns the new base function.
+     */
+    function createBaseFor(fromRight) {
+      return function(object, iteratee, keysFunc) {
+        var index = -1,
+            iterable = Object(object),
+            props = keysFunc(object),
+            length = props.length;
+
+        while (length--) {
+          var key = props[fromRight ? length : ++index];
+          if (iteratee(iterable[key], key, iterable) === false) {
+            break;
+          }
+        }
+        return object;
+      };
+    }
+
+    /**
+     * Creates a function that wraps `func` to invoke it with the optional `this`
+     * binding of `thisArg`.
+     *
+     * @private
+     * @param {Function} func The function to wrap.
+     * @param {number} bitmask The bitmask flags. See `createWrap` for more details.
+     * @param {*} [thisArg] The `this` binding of `func`.
+     * @returns {Function} Returns the new wrapped function.
+     */
+    function createBind(func, bitmask, thisArg) {
+      var isBind = bitmask & WRAP_BIND_FLAG,
+          Ctor = createCtor(func);
+
+      function wrapper() {
+        var fn = (this && this !== root && this instanceof wrapper) ? Ctor : func;
+        return fn.apply(isBind ? thisArg : this, arguments);
+      }
+      return wrapper;
+    }
+
+    /**
+     * Creates a function like `_.lowerFirst`.
+     *
+     * @private
+     * @param {string} methodName The name of the `String` case method to use.
+     * @returns {Function} Returns the new case function.
+     */
+    function createCaseFirst(methodName) {
+      return function(string) {
+        string = toString(string);
+
+        var strSymbols = hasUnicode(string)
+          ? stringToArray(string)
+          : undefined;
+
+        var chr = strSymbols
+          ? strSymbols[0]
+          : string.charAt(0);
+
+        var trailing = strSymbols
+          ? castSlice(strSymbols, 1).join('')
+          : string.slice(1);
+
+        return chr[methodName]() + trailing;
+      };
+    }
+
+    /**
+     * Creates a function like `_.camelCase`.
+     *
+     * @private
+     * @param {Function} callback The function to combine each word.
+     * @returns {Function} Returns the new compounder function.
+     */
+    function createCompounder(callback) {
+      return function(string) {
+        return arrayReduce(words(deburr(string).replace(reApos, '')), callback, '');
+      };
+    }
+
+    /**
+     * Creates a function that produces an instance of `Ctor` regardless of
+     * whether it was invoked as part of a `new` expression or by `call` or `apply`.
+     *
+     * @private
+     * @param {Function} Ctor The constructor to wrap.
+     * @returns {Function} Returns the new wrapped function.
+     */
+    function createCtor(Ctor) {
+      return function() {
+        // Use a `switch` statement to work with class constructors. See
+        // http://ecma-international.org/ecma-262/7.0/#sec-ecmascript-function-objects-call-thisargument-argumentslist
+        // for more details.
+        var args = arguments;
+        switch (args.length) {
+          case 0: return new Ctor;
+          case 1: return new Ctor(args[0]);
+          case 2: return new Ctor(args[0], args[1]);
+          case 3: return new Ctor(args[0], args[1], args[2]);
+          case 4: return new Ctor(args[0], args[1], args[2], args[3]);
+          case 5: return new Ctor(args[0], args[1], args[2], args[3], args[4]);
+          case 6: return new Ctor(args[0], args[1], args[2], args[3], args[4], args[5]);
+          case 7: return new Ctor(args[0], args[1], args[2], args[3], args[4], args[5], args[6]);
+        }
+        var thisBinding = baseCreate(Ctor.prototype),
+            result = Ctor.apply(thisBinding, args);
+
+        // Mimic the constructor's `return` behavior.
+        // See https://es5.github.io/#x13.2.2 for more details.
+        return isObject(result) ? result : thisBinding;
+      };
+    }
+
+    /**
+     * Creates a function that wraps `func` to enable currying.
+     *
+     * @private
+     * @param {Function} func The function to wrap.
+     * @param {number} bitmask The bitmask flags. See `createWrap` for more details.
+     * @param {number} arity The arity of `func`.
+     * @returns {Function} Returns the new wrapped function.
+     */
+    function createCurry(func, bitmask, arity) {
+      var Ctor = createCtor(func);
+
+      function wrapper() {
+        var length = arguments.length,
+            args = Array(length),
+            index = length,
+            placeholder = getHolder(wrapper);
+
+        while (index--) {
+          args[index] = arguments[index];
+        }
+        var holders = (length < 3 && args[0] !== placeholder && args[length - 1] !== placeholder)
+          ? []
+          : replaceHolders(args, placeholder);
+
+        length -= holders.length;
+        if (length < arity) {
+          return createRecurry(
+            func, bitmask, createHybrid, wrapper.placeholder, undefined,
+            args, holders, undefined, undefined, arity - length);
+        }
+        var fn = (this && this !== root && this instanceof wrapper) ? Ctor : func;
+        return apply(fn, this, args);
+      }
+      return wrapper;
+    }
+
+    /**
+     * Creates a `_.find` or `_.findLast` function.
+     *
+     * @private
+     * @param {Function} findIndexFunc The function to find the collection index.
+     * @returns {Function} Returns the new find function.
+     */
+    function createFind(findIndexFunc) {
+      return function(collection, predicate, fromIndex) {
+        var iterable = Object(collection);
+        if (!isArrayLike(collection)) {
+          var iteratee = getIteratee(predicate, 3);
+          collection = keys(collection);
+          predicate = function(key) { return iteratee(iterable[key], key, iterable); };
+        }
+        var index = findIndexFunc(collection, predicate, fromIndex);
+        return index > -1 ? iterable[iteratee ? collection[index] : index] : undefined;
+      };
+    }
+
+    /**
+     * Creates a `_.flow` or `_.flowRight` function.
+     *
+     * @private
+     * @param {boolean} [fromRight] Specify iterating from right to left.
+     * @returns {Function} Returns the new flow function.
+     */
+    function createFlow(fromRight) {
+      return flatRest(function(funcs) {
+        var length = funcs.length,
+            index = length,
+            prereq = LodashWrapper.prototype.thru;
+
+        if (fromRight) {
+          funcs.reverse();
+        }
+        while (index--) {
+          var func = funcs[index];
+          if (typeof func != 'function') {
+            throw new TypeError(FUNC_ERROR_TEXT);
+          }
+          if (prereq && !wrapper && getFuncName(func) == 'wrapper') {
+            var wrapper = new LodashWrapper([], true);
+          }
+        }
+        index = wrapper ? index : length;
+        while (++index < length) {
+          func = funcs[index];
+
+          var funcName = getFuncName(func),
+              data = funcName == 'wrapper' ? getData(func) : undefined;
+
+          if (data && isLaziable(data[0]) &&
+                data[1] == (WRAP_ARY_FLAG | WRAP_CURRY_FLAG | WRAP_PARTIAL_FLAG | WRAP_REARG_FLAG) &&
+                !data[4].length && data[9] == 1
+              ) {
+            wrapper = wrapper[getFuncName(data[0])].apply(wrapper, data[3]);
+          } else {
+            wrapper = (func.length == 1 && isLaziable(func))
+              ? wrapper[funcName]()
+              : wrapper.thru(func);
+          }
+        }
+        return function() {
+          var args = arguments,
+              value = args[0];
+
+          if (wrapper && args.length == 1 && isArray(value)) {
+            return wrapper.plant(value).value();
+          }
+          var index = 0,
+              result = length ? funcs[index].apply(this, args) : value;
 
           while (++index < length) {
-            var value = collection[index];
-            setter(result, value, callback(value, index, collection), collection);
+            result = funcs[index].call(this, result);
           }
-        } else {
-          baseEach(collection, function(value, key, collection) {
-            setter(result, value, callback(value, key, collection), collection);
-          });
+          return result;
+        };
+      });
+    }
+
+    /**
+     * Creates a function that wraps `func` to invoke it with optional `this`
+     * binding of `thisArg`, partial application, and currying.
+     *
+     * @private
+     * @param {Function|string} func The function or method name to wrap.
+     * @param {number} bitmask The bitmask flags. See `createWrap` for more details.
+     * @param {*} [thisArg] The `this` binding of `func`.
+     * @param {Array} [partials] The arguments to prepend to those provided to
+     *  the new function.
+     * @param {Array} [holders] The `partials` placeholder indexes.
+     * @param {Array} [partialsRight] The arguments to append to those provided
+     *  to the new function.
+     * @param {Array} [holdersRight] The `partialsRight` placeholder indexes.
+     * @param {Array} [argPos] The argument positions of the new function.
+     * @param {number} [ary] The arity cap of `func`.
+     * @param {number} [arity] The arity of `func`.
+     * @returns {Function} Returns the new wrapped function.
+     */
+    function createHybrid(func, bitmask, thisArg, partials, holders, partialsRight, holdersRight, argPos, ary, arity) {
+      var isAry = bitmask & WRAP_ARY_FLAG,
+          isBind = bitmask & WRAP_BIND_FLAG,
+          isBindKey = bitmask & WRAP_BIND_KEY_FLAG,
+          isCurried = bitmask & (WRAP_CURRY_FLAG | WRAP_CURRY_RIGHT_FLAG),
+          isFlip = bitmask & WRAP_FLIP_FLAG,
+          Ctor = isBindKey ? undefined : createCtor(func);
+
+      function wrapper() {
+        var length = arguments.length,
+            args = Array(length),
+            index = length;
+
+        while (index--) {
+          args[index] = arguments[index];
+        }
+        if (isCurried) {
+          var placeholder = getHolder(wrapper),
+              holdersCount = countHolders(args, placeholder);
+        }
+        if (partials) {
+          args = composeArgs(args, partials, holders, isCurried);
+        }
+        if (partialsRight) {
+          args = composeArgsRight(args, partialsRight, holdersRight, isCurried);
+        }
+        length -= holdersCount;
+        if (isCurried && length < arity) {
+          var newHolders = replaceHolders(args, placeholder);
+          return createRecurry(
+            func, bitmask, createHybrid, wrapper.placeholder, thisArg,
+            args, newHolders, argPos, ary, arity - length
+          );
+        }
+        var thisBinding = isBind ? thisArg : this,
+            fn = isBindKey ? thisBinding[func] : func;
+
+        length = args.length;
+        if (argPos) {
+          args = reorder(args, argPos);
+        } else if (isFlip && length > 1) {
+          args.reverse();
+        }
+        if (isAry && ary < length) {
+          args.length = ary;
+        }
+        if (this && this !== root && this instanceof wrapper) {
+          fn = Ctor || createCtor(fn);
+        }
+        return fn.apply(thisBinding, args);
+      }
+      return wrapper;
+    }
+
+    /**
+     * Creates a function like `_.invertBy`.
+     *
+     * @private
+     * @param {Function} setter The function to set accumulator values.
+     * @param {Function} toIteratee The function to resolve iteratees.
+     * @returns {Function} Returns the new inverter function.
+     */
+    function createInverter(setter, toIteratee) {
+      return function(object, iteratee) {
+        return baseInverter(object, setter, toIteratee(iteratee), {});
+      };
+    }
+
+    /**
+     * Creates a function that performs a mathematical operation on two values.
+     *
+     * @private
+     * @param {Function} operator The function to perform the operation.
+     * @param {number} [defaultValue] The value used for `undefined` arguments.
+     * @returns {Function} Returns the new mathematical operation function.
+     */
+    function createMathOperation(operator, defaultValue) {
+      return function(value, other) {
+        var result;
+        if (value === undefined && other === undefined) {
+          return defaultValue;
+        }
+        if (value !== undefined) {
+          result = value;
+        }
+        if (other !== undefined) {
+          if (result === undefined) {
+            return other;
+          }
+          if (typeof value == 'string' || typeof other == 'string') {
+            value = baseToString(value);
+            other = baseToString(other);
+          } else {
+            value = baseToNumber(value);
+            other = baseToNumber(other);
+          }
+          result = operator(value, other);
         }
         return result;
       };
     }
 
     /**
-     * Creates a function that, when called, either curries or invokes `func`
-     * with an optional `this` binding and partially applied arguments.
+     * Creates a function like `_.over`.
+     *
+     * @private
+     * @param {Function} arrayFunc The function to iterate over iteratees.
+     * @returns {Function} Returns the new over function.
+     */
+    function createOver(arrayFunc) {
+      return flatRest(function(iteratees) {
+        iteratees = arrayMap(iteratees, baseUnary(getIteratee()));
+        return baseRest(function(args) {
+          var thisArg = this;
+          return arrayFunc(iteratees, function(iteratee) {
+            return apply(iteratee, thisArg, args);
+          });
+        });
+      });
+    }
+
+    /**
+     * Creates the padding for `string` based on `length`. The `chars` string
+     * is truncated if the number of characters exceeds `length`.
      *
      * @private
-     * @param {Function|string} func The function or method name to reference.
-     * @param {number} bitmask The bitmask of method flags to compose.
-     *  The bitmask may be composed of the following flags:
-     *  1 - `_.bind`
-     *  2 - `_.bindKey`
-     *  4 - `_.curry`
-     *  8 - `_.curry` (bound)
-     *  16 - `_.partial`
-     *  32 - `_.partialRight`
-     * @param {Array} [partialArgs] An array of arguments to prepend to those
-     *  provided to the new function.
-     * @param {Array} [partialRightArgs] An array of arguments to append to those
-     *  provided to the new function.
+     * @param {number} length The padding length.
+     * @param {string} [chars=' '] The string used as padding.
+     * @returns {string} Returns the padding for `string`.
+     */
+    function createPadding(length, chars) {
+      chars = chars === undefined ? ' ' : baseToString(chars);
+
+      var charsLength = chars.length;
+      if (charsLength < 2) {
+        return charsLength ? baseRepeat(chars, length) : chars;
+      }
+      var result = baseRepeat(chars, nativeCeil(length / stringSize(chars)));
+      return hasUnicode(chars)
+        ? castSlice(stringToArray(result), 0, length).join('')
+        : result.slice(0, length);
+    }
+
+    /**
+     * Creates a function that wraps `func` to invoke it with the `this` binding
+     * of `thisArg` and `partials` prepended to the arguments it receives.
+     *
+     * @private
+     * @param {Function} func The function to wrap.
+     * @param {number} bitmask The bitmask flags. See `createWrap` for more details.
+     * @param {*} thisArg The `this` binding of `func`.
+     * @param {Array} partials The arguments to prepend to those provided to
+     *  the new function.
+     * @returns {Function} Returns the new wrapped function.
+     */
+    function createPartial(func, bitmask, thisArg, partials) {
+      var isBind = bitmask & WRAP_BIND_FLAG,
+          Ctor = createCtor(func);
+
+      function wrapper() {
+        var argsIndex = -1,
+            argsLength = arguments.length,
+            leftIndex = -1,
+            leftLength = partials.length,
+            args = Array(leftLength + argsLength),
+            fn = (this && this !== root && this instanceof wrapper) ? Ctor : func;
+
+        while (++leftIndex < leftLength) {
+          args[leftIndex] = partials[leftIndex];
+        }
+        while (argsLength--) {
+          args[leftIndex++] = arguments[++argsIndex];
+        }
+        return apply(fn, isBind ? thisArg : this, args);
+      }
+      return wrapper;
+    }
+
+    /**
+     * Creates a `_.range` or `_.rangeRight` function.
+     *
+     * @private
+     * @param {boolean} [fromRight] Specify iterating from right to left.
+     * @returns {Function} Returns the new range function.
+     */
+    function createRange(fromRight) {
+      return function(start, end, step) {
+        if (step && typeof step != 'number' && isIterateeCall(start, end, step)) {
+          end = step = undefined;
+        }
+        // Ensure the sign of `-0` is preserved.
+        start = toFinite(start);
+        if (end === undefined) {
+          end = start;
+          start = 0;
+        } else {
+          end = toFinite(end);
+        }
+        step = step === undefined ? (start < end ? 1 : -1) : toFinite(step);
+        return baseRange(start, end, step, fromRight);
+      };
+    }
+
+    /**
+     * Creates a function that performs a relational operation on two values.
+     *
+     * @private
+     * @param {Function} operator The function to perform the operation.
+     * @returns {Function} Returns the new relational operation function.
+     */
+    function createRelationalOperation(operator) {
+      return function(value, other) {
+        if (!(typeof value == 'string' && typeof other == 'string')) {
+          value = toNumber(value);
+          other = toNumber(other);
+        }
+        return operator(value, other);
+      };
+    }
+
+    /**
+     * Creates a function that wraps `func` to continue currying.
+     *
+     * @private
+     * @param {Function} func The function to wrap.
+     * @param {number} bitmask The bitmask flags. See `createWrap` for more details.
+     * @param {Function} wrapFunc The function to create the `func` wrapper.
+     * @param {*} placeholder The placeholder value.
+     * @param {*} [thisArg] The `this` binding of `func`.
+     * @param {Array} [partials] The arguments to prepend to those provided to
+     *  the new function.
+     * @param {Array} [holders] The `partials` placeholder indexes.
+     * @param {Array} [argPos] The argument positions of the new function.
+     * @param {number} [ary] The arity cap of `func`.
+     * @param {number} [arity] The arity of `func`.
+     * @returns {Function} Returns the new wrapped function.
+     */
+    function createRecurry(func, bitmask, wrapFunc, placeholder, thisArg, partials, holders, argPos, ary, arity) {
+      var isCurry = bitmask & WRAP_CURRY_FLAG,
+          newHolders = isCurry ? holders : undefined,
+          newHoldersRight = isCurry ? undefined : holders,
+          newPartials = isCurry ? partials : undefined,
+          newPartialsRight = isCurry ? undefined : partials;
+
+      bitmask |= (isCurry ? WRAP_PARTIAL_FLAG : WRAP_PARTIAL_RIGHT_FLAG);
+      bitmask &= ~(isCurry ? WRAP_PARTIAL_RIGHT_FLAG : WRAP_PARTIAL_FLAG);
+
+      if (!(bitmask & WRAP_CURRY_BOUND_FLAG)) {
+        bitmask &= ~(WRAP_BIND_FLAG | WRAP_BIND_KEY_FLAG);
+      }
+      var newData = [
+        func, bitmask, thisArg, newPartials, newHolders, newPartialsRight,
+        newHoldersRight, argPos, ary, arity
+      ];
+
+      var result = wrapFunc.apply(undefined, newData);
+      if (isLaziable(func)) {
+        setData(result, newData);
+      }
+      result.placeholder = placeholder;
+      return setWrapToString(result, func, bitmask);
+    }
+
+    /**
+     * Creates a function like `_.round`.
+     *
+     * @private
+     * @param {string} methodName The name of the `Math` method to use when rounding.
+     * @returns {Function} Returns the new round function.
+     */
+    function createRound(methodName) {
+      var func = Math[methodName];
+      return function(number, precision) {
+        number = toNumber(number);
+        precision = precision == null ? 0 : nativeMin(toInteger(precision), 292);
+        if (precision && nativeIsFinite(number)) {
+          // Shift with exponential notation to avoid floating-point issues.
+          // See [MDN](https://mdn.io/round#Examples) for more details.
+          var pair = (toString(number) + 'e').split('e'),
+              value = func(pair[0] + 'e' + (+pair[1] + precision));
+
+          pair = (toString(value) + 'e').split('e');
+          return +(pair[0] + 'e' + (+pair[1] - precision));
+        }
+        return func(number);
+      };
+    }
+
+    /**
+     * Creates a set object of `values`.
+     *
+     * @private
+     * @param {Array} values The values to add to the set.
+     * @returns {Object} Returns the new set.
+     */
+    var createSet = !(Set && (1 / setToArray(new Set([,-0]))[1]) == INFINITY) ? noop : function(values) {
+      return new Set(values);
+    };
+
+    /**
+     * Creates a `_.toPairs` or `_.toPairsIn` function.
+     *
+     * @private
+     * @param {Function} keysFunc The function to get the keys of a given object.
+     * @returns {Function} Returns the new pairs function.
+     */
+    function createToPairs(keysFunc) {
+      return function(object) {
+        var tag = getTag(object);
+        if (tag == mapTag) {
+          return mapToArray(object);
+        }
+        if (tag == setTag) {
+          return setToPairs(object);
+        }
+        return baseToPairs(object, keysFunc(object));
+      };
+    }
+
+    /**
+     * Creates a function that either curries or invokes `func` with optional
+     * `this` binding and partially applied arguments.
+     *
+     * @private
+     * @param {Function|string} func The function or method name to wrap.
+     * @param {number} bitmask The bitmask flags.
+     *    1 - `_.bind`
+     *    2 - `_.bindKey`
+     *    4 - `_.curry` or `_.curryRight` of a bound function
+     *    8 - `_.curry`
+     *   16 - `_.curryRight`
+     *   32 - `_.partial`
+     *   64 - `_.partialRight`
+     *  128 - `_.rearg`
+     *  256 - `_.ary`
+     *  512 - `_.flip`
      * @param {*} [thisArg] The `this` binding of `func`.
+     * @param {Array} [partials] The arguments to be partially applied.
+     * @param {Array} [holders] The `partials` placeholder indexes.
+     * @param {Array} [argPos] The argument positions of the new function.
+     * @param {number} [ary] The arity cap of `func`.
      * @param {number} [arity] The arity of `func`.
+     * @returns {Function} Returns the new wrapped function.
+     */
+    function createWrap(func, bitmask, thisArg, partials, holders, argPos, ary, arity) {
+      var isBindKey = bitmask & WRAP_BIND_KEY_FLAG;
+      if (!isBindKey && typeof func != 'function') {
+        throw new TypeError(FUNC_ERROR_TEXT);
+      }
+      var length = partials ? partials.length : 0;
+      if (!length) {
+        bitmask &= ~(WRAP_PARTIAL_FLAG | WRAP_PARTIAL_RIGHT_FLAG);
+        partials = holders = undefined;
+      }
+      ary = ary === undefined ? ary : nativeMax(toInteger(ary), 0);
+      arity = arity === undefined ? arity : toInteger(arity);
+      length -= holders ? holders.length : 0;
+
+      if (bitmask & WRAP_PARTIAL_RIGHT_FLAG) {
+        var partialsRight = partials,
+            holdersRight = holders;
+
+        partials = holders = undefined;
+      }
+      var data = isBindKey ? undefined : getData(func);
+
+      var newData = [
+        func, bitmask, thisArg, partials, holders, partialsRight, holdersRight,
+        argPos, ary, arity
+      ];
+
+      if (data) {
+        mergeData(newData, data);
+      }
+      func = newData[0];
+      bitmask = newData[1];
+      thisArg = newData[2];
+      partials = newData[3];
+      holders = newData[4];
+      arity = newData[9] = newData[9] === undefined
+        ? (isBindKey ? 0 : func.length)
+        : nativeMax(newData[9] - length, 0);
+
+      if (!arity && bitmask & (WRAP_CURRY_FLAG | WRAP_CURRY_RIGHT_FLAG)) {
+        bitmask &= ~(WRAP_CURRY_FLAG | WRAP_CURRY_RIGHT_FLAG);
+      }
+      if (!bitmask || bitmask == WRAP_BIND_FLAG) {
+        var result = createBind(func, bitmask, thisArg);
+      } else if (bitmask == WRAP_CURRY_FLAG || bitmask == WRAP_CURRY_RIGHT_FLAG) {
+        result = createCurry(func, bitmask, arity);
+      } else if ((bitmask == WRAP_PARTIAL_FLAG || bitmask == (WRAP_BIND_FLAG | WRAP_PARTIAL_FLAG)) && !holders.length) {
+        result = createPartial(func, bitmask, thisArg, partials);
+      } else {
+        result = createHybrid.apply(undefined, newData);
+      }
+      var setter = data ? baseSetData : setData;
+      return setWrapToString(setter(result, newData), func, bitmask);
+    }
+
+    /**
+     * Used by `_.defaults` to customize its `_.assignIn` use to assign properties
+     * of source objects to the destination object for all destination properties
+     * that resolve to `undefined`.
+     *
+     * @private
+     * @param {*} objValue The destination value.
+     * @param {*} srcValue The source value.
+     * @param {string} key The key of the property to assign.
+     * @param {Object} object The parent object of `objValue`.
+     * @returns {*} Returns the value to assign.
+     */
+    function customDefaultsAssignIn(objValue, srcValue, key, object) {
+      if (objValue === undefined ||
+          (eq(objValue, objectProto[key]) && !hasOwnProperty.call(object, key))) {
+        return srcValue;
+      }
+      return objValue;
+    }
+
+    /**
+     * Used by `_.defaultsDeep` to customize its `_.merge` use to merge source
+     * objects into destination objects that are passed thru.
+     *
+     * @private
+     * @param {*} objValue The destination value.
+     * @param {*} srcValue The source value.
+     * @param {string} key The key of the property to merge.
+     * @param {Object} object The parent object of `objValue`.
+     * @param {Object} source The parent object of `srcValue`.
+     * @param {Object} [stack] Tracks traversed source values and their merged
+     *  counterparts.
+     * @returns {*} Returns the value to assign.
+     */
+    function customDefaultsMerge(objValue, srcValue, key, object, source, stack) {
+      if (isObject(objValue) && isObject(srcValue)) {
+        // Recursively merge objects and arrays (susceptible to call stack limits).
+        stack.set(srcValue, objValue);
+        baseMerge(objValue, srcValue, undefined, customDefaultsMerge, stack);
+        stack['delete'](srcValue);
+      }
+      return objValue;
+    }
+
+    /**
+     * Used by `_.omit` to customize its `_.cloneDeep` use to only clone plain
+     * objects.
+     *
+     * @private
+     * @param {*} value The value to inspect.
+     * @param {string} key The key of the property to inspect.
+     * @returns {*} Returns the uncloned value or `undefined` to defer cloning to `_.cloneDeep`.
+     */
+    function customOmitClone(value) {
+      return isPlainObject(value) ? undefined : value;
+    }
+
+    /**
+     * A specialized version of `baseIsEqualDeep` for arrays with support for
+     * partial deep comparisons.
+     *
+     * @private
+     * @param {Array} array The array to compare.
+     * @param {Array} other The other array to compare.
+     * @param {number} bitmask The bitmask flags. See `baseIsEqual` for more details.
+     * @param {Function} customizer The function to customize comparisons.
+     * @param {Function} equalFunc The function to determine equivalents of values.
+     * @param {Object} stack Tracks traversed `array` and `other` objects.
+     * @returns {boolean} Returns `true` if the arrays are equivalent, else `false`.
+     */
+    function equalArrays(array, other, bitmask, customizer, equalFunc, stack) {
+      var isPartial = bitmask & COMPARE_PARTIAL_FLAG,
+          arrLength = array.length,
+          othLength = other.length;
+
+      if (arrLength != othLength && !(isPartial && othLength > arrLength)) {
+        return false;
+      }
+      // Check that cyclic values are equal.
+      var arrStacked = stack.get(array);
+      var othStacked = stack.get(other);
+      if (arrStacked && othStacked) {
+        return arrStacked == other && othStacked == array;
+      }
+      var index = -1,
+          result = true,
+          seen = (bitmask & COMPARE_UNORDERED_FLAG) ? new SetCache : undefined;
+
+      stack.set(array, other);
+      stack.set(other, array);
+
+      // Ignore non-index properties.
+      while (++index < arrLength) {
+        var arrValue = array[index],
+            othValue = other[index];
+
+        if (customizer) {
+          var compared = isPartial
+            ? customizer(othValue, arrValue, index, other, array, stack)
+            : customizer(arrValue, othValue, index, array, other, stack);
+        }
+        if (compared !== undefined) {
+          if (compared) {
+            continue;
+          }
+          result = false;
+          break;
+        }
+        // Recursively compare arrays (susceptible to call stack limits).
+        if (seen) {
+          if (!arraySome(other, function(othValue, othIndex) {
+                if (!cacheHas(seen, othIndex) &&
+                    (arrValue === othValue || equalFunc(arrValue, othValue, bitmask, customizer, stack))) {
+                  return seen.push(othIndex);
+                }
+              })) {
+            result = false;
+            break;
+          }
+        } else if (!(
+              arrValue === othValue ||
+                equalFunc(arrValue, othValue, bitmask, customizer, stack)
+            )) {
+          result = false;
+          break;
+        }
+      }
+      stack['delete'](array);
+      stack['delete'](other);
+      return result;
+    }
+
+    /**
+     * A specialized version of `baseIsEqualDeep` for comparing objects of
+     * the same `toStringTag`.
+     *
+     * **Note:** This function only supports comparing values with tags of
+     * `Boolean`, `Date`, `Error`, `Number`, `RegExp`, or `String`.
+     *
+     * @private
+     * @param {Object} object The object to compare.
+     * @param {Object} other The other object to compare.
+     * @param {string} tag The `toStringTag` of the objects to compare.
+     * @param {number} bitmask The bitmask flags. See `baseIsEqual` for more details.
+     * @param {Function} customizer The function to customize comparisons.
+     * @param {Function} equalFunc The function to determine equivalents of values.
+     * @param {Object} stack Tracks traversed `object` and `other` objects.
+     * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
+     */
+    function equalByTag(object, other, tag, bitmask, customizer, equalFunc, stack) {
+      switch (tag) {
+        case dataViewTag:
+          if ((object.byteLength != other.byteLength) ||
+              (object.byteOffset != other.byteOffset)) {
+            return false;
+          }
+          object = object.buffer;
+          other = other.buffer;
+
+        case arrayBufferTag:
+          if ((object.byteLength != other.byteLength) ||
+              !equalFunc(new Uint8Array(object), new Uint8Array(other))) {
+            return false;
+          }
+          return true;
+
+        case boolTag:
+        case dateTag:
+        case numberTag:
+          // Coerce booleans to `1` or `0` and dates to milliseconds.
+          // Invalid dates are coerced to `NaN`.
+          return eq(+object, +other);
+
+        case errorTag:
+          return object.name == other.name && object.message == other.message;
+
+        case regexpTag:
+        case stringTag:
+          // Coerce regexes to strings and treat strings, primitives and objects,
+          // as equal. See http://www.ecma-international.org/ecma-262/7.0/#sec-regexp.prototype.tostring
+          // for more details.
+          return object == (other + '');
+
+        case mapTag:
+          var convert = mapToArray;
+
+        case setTag:
+          var isPartial = bitmask & COMPARE_PARTIAL_FLAG;
+          convert || (convert = setToArray);
+
+          if (object.size != other.size && !isPartial) {
+            return false;
+          }
+          // Assume cyclic values are equal.
+          var stacked = stack.get(object);
+          if (stacked) {
+            return stacked == other;
+          }
+          bitmask |= COMPARE_UNORDERED_FLAG;
+
+          // Recursively compare objects (susceptible to call stack limits).
+          stack.set(object, other);
+          var result = equalArrays(convert(object), convert(other), bitmask, customizer, equalFunc, stack);
+          stack['delete'](object);
+          return result;
+
+        case symbolTag:
+          if (symbolValueOf) {
+            return symbolValueOf.call(object) == symbolValueOf.call(other);
+          }
+      }
+      return false;
+    }
+
+    /**
+     * A specialized version of `baseIsEqualDeep` for objects with support for
+     * partial deep comparisons.
+     *
+     * @private
+     * @param {Object} object The object to compare.
+     * @param {Object} other The other object to compare.
+     * @param {number} bitmask The bitmask flags. See `baseIsEqual` for more details.
+     * @param {Function} customizer The function to customize comparisons.
+     * @param {Function} equalFunc The function to determine equivalents of values.
+     * @param {Object} stack Tracks traversed `object` and `other` objects.
+     * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
+     */
+    function equalObjects(object, other, bitmask, customizer, equalFunc, stack) {
+      var isPartial = bitmask & COMPARE_PARTIAL_FLAG,
+          objProps = getAllKeys(object),
+          objLength = objProps.length,
+          othProps = getAllKeys(other),
+          othLength = othProps.length;
+
+      if (objLength != othLength && !isPartial) {
+        return false;
+      }
+      var index = objLength;
+      while (index--) {
+        var key = objProps[index];
+        if (!(isPartial ? key in other : hasOwnProperty.call(other, key))) {
+          return false;
+        }
+      }
+      // Check that cyclic values are equal.
+      var objStacked = stack.get(object);
+      var othStacked = stack.get(other);
+      if (objStacked && othStacked) {
+        return objStacked == other && othStacked == object;
+      }
+      var result = true;
+      stack.set(object, other);
+      stack.set(other, object);
+
+      var skipCtor = isPartial;
+      while (++index < objLength) {
+        key = objProps[index];
+        var objValue = object[key],
+            othValue = other[key];
+
+        if (customizer) {
+          var compared = isPartial
+            ? customizer(othValue, objValue, key, other, object, stack)
+            : customizer(objValue, othValue, key, object, other, stack);
+        }
+        // Recursively compare objects (susceptible to call stack limits).
+        if (!(compared === undefined
+              ? (objValue === othValue || equalFunc(objValue, othValue, bitmask, customizer, stack))
+              : compared
+            )) {
+          result = false;
+          break;
+        }
+        skipCtor || (skipCtor = key == 'constructor');
+      }
+      if (result && !skipCtor) {
+        var objCtor = object.constructor,
+            othCtor = other.constructor;
+
+        // Non `Object` object instances with different constructors are not equal.
+        if (objCtor != othCtor &&
+            ('constructor' in object && 'constructor' in other) &&
+            !(typeof objCtor == 'function' && objCtor instanceof objCtor &&
+              typeof othCtor == 'function' && othCtor instanceof othCtor)) {
+          result = false;
+        }
+      }
+      stack['delete'](object);
+      stack['delete'](other);
+      return result;
+    }
+
+    /**
+     * A specialized version of `baseRest` which flattens the rest array.
+     *
+     * @private
+     * @param {Function} func The function to apply a rest parameter to.
      * @returns {Function} Returns the new function.
      */
-    function createWrapper(func, bitmask, partialArgs, partialRightArgs, thisArg, arity) {
-      var isBind = bitmask & 1,
-          isBindKey = bitmask & 2,
-          isCurry = bitmask & 4,
-          isCurryBound = bitmask & 8,
-          isPartial = bitmask & 16,
-          isPartialRight = bitmask & 32;
-
-      if (!isBindKey && !isFunction(func)) {
-        throw new TypeError;
-      }
-      if (isPartial && !partialArgs.length) {
-        bitmask &= ~16;
-        isPartial = partialArgs = false;
-      }
-      if (isPartialRight && !partialRightArgs.length) {
-        bitmask &= ~32;
-        isPartialRight = partialRightArgs = false;
-      }
-      var bindData = func && func.__bindData__;
-      if (bindData && bindData !== true) {
-        // clone `bindData`
-        bindData = slice(bindData);
-        if (bindData[2]) {
-          bindData[2] = slice(bindData[2]);
-        }
-        if (bindData[3]) {
-          bindData[3] = slice(bindData[3]);
-        }
-        // set `thisBinding` is not previously bound
-        if (isBind && !(bindData[1] & 1)) {
-          bindData[4] = thisArg;
-        }
-        // set if previously bound but not currently (subsequent curried functions)
-        if (!isBind && bindData[1] & 1) {
-          bitmask |= 8;
-        }
-        // set curried arity if not yet set
-        if (isCurry && !(bindData[1] & 4)) {
-          bindData[5] = arity;
-        }
-        // append partial left arguments
-        if (isPartial) {
-          push.apply(bindData[2] || (bindData[2] = []), partialArgs);
-        }
-        // append partial right arguments
-        if (isPartialRight) {
-          unshift.apply(bindData[3] || (bindData[3] = []), partialRightArgs);
-        }
-        // merge flags
-        bindData[1] |= bitmask;
-        return createWrapper.apply(null, bindData);
-      }
-      // fast path for `_.bind`
-      var creater = (bitmask == 1 || bitmask === 17) ? baseBind : baseCreateWrapper;
-      return creater([func, bitmask, partialArgs, partialRightArgs, thisArg, arity]);
-    }
-
-    /**
-     * Creates compiled iteration functions.
-     *
-     * @private
-     * @param {...Object} [options] The compile options object(s).
-     * @param {string} [options.array] Code to determine if the iterable is an array or array-like.
-     * @param {boolean} [options.useHas] Specify using `hasOwnProperty` checks in the object loop.
-     * @param {Function} [options.keys] A reference to `_.keys` for use in own property iteration.
-     * @param {string} [options.args] A comma separated string of iteration function arguments.
-     * @param {string} [options.top] Code to execute before the iteration branches.
-     * @param {string} [options.loop] Code to execute in the object loop.
-     * @param {string} [options.bottom] Code to execute after the iteration branches.
-     * @returns {Function} Returns the compiled function.
-     */
-    function createIterator() {
-      // data properties
-      iteratorData.shadowedProps = shadowedProps;
-      iteratorData.support = support;
-
-      // iterator options
-      iteratorData.array = iteratorData.bottom = iteratorData.loop = iteratorData.top = '';
-      iteratorData.init = 'iterable';
-      iteratorData.useHas = true;
-
-      // merge options into a template data object
-      for (var object, index = 0; object = arguments[index]; index++) {
-        for (var key in object) {
-          iteratorData[key] = object[key];
-        }
-      }
-      var args = iteratorData.args;
-      iteratorData.firstArg = /^[^,]+/.exec(args)[0];
-
-      // create the function factory
-      var factory = Function(
-          'baseCreateCallback, errorClass, errorProto, hasOwnProperty, ' +
-          'indicatorObject, isArguments, isArray, isString, keys, objectProto, ' +
-          'objectTypes, nonEnumProps, stringClass, stringProto, toString',
-        'return function(' + args + ') {\n' + iteratorTemplate(iteratorData) + '\n}'
-      );
+    function flatRest(func) {
+      return setToString(overRest(func, undefined, flatten), func + '');
+    }
 
-      // return the compiled function
-      return factory(
-        baseCreateCallback, errorClass, errorProto, hasOwnProperty,
-        indicatorObject, isArguments, isArray, isString, iteratorData.keys, objectProto,
-        objectTypes, nonEnumProps, stringClass, stringProto, toString
-      );
+    /**
+     * Creates an array of own enumerable property names and symbols of `object`.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the array of property names and symbols.
+     */
+    function getAllKeys(object) {
+      return baseGetAllKeys(object, keys, getSymbols);
     }
 
     /**
-     * Used by `escape` to convert characters to HTML entities.
+     * Creates an array of own and inherited enumerable property names and
+     * symbols of `object`.
      *
      * @private
-     * @param {string} match The matched character to escape.
-     * @returns {string} Returns the escaped character.
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the array of property names and symbols.
      */
-    function escapeHtmlChar(match) {
-      return htmlEscapes[match];
+    function getAllKeysIn(object) {
+      return baseGetAllKeys(object, keysIn, getSymbolsIn);
     }
 
     /**
-     * Gets the appropriate "indexOf" function. If the `_.indexOf` method is
-     * customized, this method returns the custom method, otherwise it returns
-     * the `baseIndexOf` function.
+     * Gets metadata for `func`.
+     *
+     * @private
+     * @param {Function} func The function to query.
+     * @returns {*} Returns the metadata for `func`.
+     */
+    var getData = !metaMap ? noop : function(func) {
+      return metaMap.get(func);
+    };
+
+    /**
+     * Gets the name of `func`.
      *
      * @private
-     * @returns {Function} Returns the "indexOf" function.
+     * @param {Function} func The function to query.
+     * @returns {string} Returns the function name.
      */
-    function getIndexOf() {
-      var result = (result = lodash.indexOf) === indexOf ? baseIndexOf : result;
+    function getFuncName(func) {
+      var result = (func.name + ''),
+          array = realNames[result],
+          length = hasOwnProperty.call(realNames, result) ? array.length : 0;
+
+      while (length--) {
+        var data = array[length],
+            otherFunc = data.func;
+        if (otherFunc == null || otherFunc == func) {
+          return data.name;
+        }
+      }
       return result;
     }
 
     /**
-     * Checks if `value` is a native function.
+     * Gets the argument placeholder value for `func`.
      *
      * @private
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a native function, else `false`.
+     * @param {Function} func The function to inspect.
+     * @returns {*} Returns the placeholder value.
      */
-    function isNative(value) {
-      return typeof value == 'function' && reNative.test(value);
+    function getHolder(func) {
+      var object = hasOwnProperty.call(lodash, 'placeholder') ? lodash : func;
+      return object.placeholder;
+    }
+
+    /**
+     * Gets the appropriate "iteratee" function. If `_.iteratee` is customized,
+     * this function returns the custom method, otherwise it returns `baseIteratee`.
+     * If arguments are provided, the chosen function is invoked with them and
+     * its result is returned.
+     *
+     * @private
+     * @param {*} [value] The value to convert to an iteratee.
+     * @param {number} [arity] The arity of the created iteratee.
+     * @returns {Function} Returns the chosen function or its result.
+     */
+    function getIteratee() {
+      var result = lodash.iteratee || iteratee;
+      result = result === iteratee ? baseIteratee : result;
+      return arguments.length ? result(arguments[0], arguments[1]) : result;
+    }
+
+    /**
+     * Gets the data for `map`.
+     *
+     * @private
+     * @param {Object} map The map to query.
+     * @param {string} key The reference key.
+     * @returns {*} Returns the map data.
+     */
+    function getMapData(map, key) {
+      var data = map.__data__;
+      return isKeyable(key)
+        ? data[typeof key == 'string' ? 'string' : 'hash']
+        : data.map;
+    }
+
+    /**
+     * Gets the property names, values, and compare flags of `object`.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the match data of `object`.
+     */
+    function getMatchData(object) {
+      var result = keys(object),
+          length = result.length;
+
+      while (length--) {
+        var key = result[length],
+            value = object[key];
+
+        result[length] = [key, value, isStrictComparable(value)];
+      }
+      return result;
     }
 
     /**
-     * Sets `this` binding data on a given function.
+     * Gets the native function at `key` of `object`.
      *
      * @private
-     * @param {Function} func The function to set data on.
-     * @param {Array} value The data array to set.
+     * @param {Object} object The object to query.
+     * @param {string} key The key of the method to get.
+     * @returns {*} Returns the function if it's native, else `undefined`.
      */
-    var setBindData = !defineProperty ? noop : function(func, value) {
-      descriptor.value = value;
-      defineProperty(func, '__bindData__', descriptor);
-      descriptor.value = null;
+    function getNative(object, key) {
+      var value = getValue(object, key);
+      return baseIsNative(value) ? value : undefined;
+    }
+
+    /**
+     * A specialized version of `baseGetTag` which ignores `Symbol.toStringTag` values.
+     *
+     * @private
+     * @param {*} value The value to query.
+     * @returns {string} Returns the raw `toStringTag`.
+     */
+    function getRawTag(value) {
+      var isOwn = hasOwnProperty.call(value, symToStringTag),
+          tag = value[symToStringTag];
+
+      try {
+        value[symToStringTag] = undefined;
+        var unmasked = true;
+      } catch (e) {}
+
+      var result = nativeObjectToString.call(value);
+      if (unmasked) {
+        if (isOwn) {
+          value[symToStringTag] = tag;
+        } else {
+          delete value[symToStringTag];
+        }
+      }
+      return result;
+    }
+
+    /**
+     * Creates an array of the own enumerable symbols of `object`.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the array of symbols.
+     */
+    var getSymbols = !nativeGetSymbols ? stubArray : function(object) {
+      if (object == null) {
+        return [];
+      }
+      object = Object(object);
+      return arrayFilter(nativeGetSymbols(object), function(symbol) {
+        return propertyIsEnumerable.call(object, symbol);
+      });
+    };
+
+    /**
+     * Creates an array of the own and inherited enumerable symbols of `object`.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the array of symbols.
+     */
+    var getSymbolsIn = !nativeGetSymbols ? stubArray : function(object) {
+      var result = [];
+      while (object) {
+        arrayPush(result, getSymbols(object));
+        object = getPrototype(object);
+      }
+      return result;
     };
 
     /**
-     * A fallback implementation of `isPlainObject` which checks if a given value
-     * is an object created by the `Object` constructor, assuming objects created
-     * by the `Object` constructor have no inherited enumerable properties and that
-     * there are no `Object.prototype` extensions.
+     * Gets the `toStringTag` of `value`.
+     *
+     * @private
+     * @param {*} value The value to query.
+     * @returns {string} Returns the `toStringTag`.
+     */
+    var getTag = baseGetTag;
+
+    // Fallback for data views, maps, sets, and weak maps in IE 11 and promises in Node.js < 6.
+    if ((DataView && getTag(new DataView(new ArrayBuffer(1))) != dataViewTag) ||
+        (Map && getTag(new Map) != mapTag) ||
+        (Promise && getTag(Promise.resolve()) != promiseTag) ||
+        (Set && getTag(new Set) != setTag) ||
+        (WeakMap && getTag(new WeakMap) != weakMapTag)) {
+      getTag = function(value) {
+        var result = baseGetTag(value),
+            Ctor = result == objectTag ? value.constructor : undefined,
+            ctorString = Ctor ? toSource(Ctor) : '';
+
+        if (ctorString) {
+          switch (ctorString) {
+            case dataViewCtorString: return dataViewTag;
+            case mapCtorString: return mapTag;
+            case promiseCtorString: return promiseTag;
+            case setCtorString: return setTag;
+            case weakMapCtorString: return weakMapTag;
+          }
+        }
+        return result;
+      };
+    }
+
+    /**
+     * Gets the view, applying any `transforms` to the `start` and `end` positions.
+     *
+     * @private
+     * @param {number} start The start of the view.
+     * @param {number} end The end of the view.
+     * @param {Array} transforms The transformations to apply to the view.
+     * @returns {Object} Returns an object containing the `start` and `end`
+     *  positions of the view.
+     */
+    function getView(start, end, transforms) {
+      var index = -1,
+          length = transforms.length;
+
+      while (++index < length) {
+        var data = transforms[index],
+            size = data.size;
+
+        switch (data.type) {
+          case 'drop':      start += size; break;
+          case 'dropRight': end -= size; break;
+          case 'take':      end = nativeMin(end, start + size); break;
+          case 'takeRight': start = nativeMax(start, end - size); break;
+        }
+      }
+      return { 'start': start, 'end': end };
+    }
+
+    /**
+     * Extracts wrapper details from the `source` body comment.
+     *
+     * @private
+     * @param {string} source The source to inspect.
+     * @returns {Array} Returns the wrapper details.
+     */
+    function getWrapDetails(source) {
+      var match = source.match(reWrapDetails);
+      return match ? match[1].split(reSplitDetails) : [];
+    }
+
+    /**
+     * Checks if `path` exists on `object`.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @param {Array|string} path The path to check.
+     * @param {Function} hasFunc The function to check properties.
+     * @returns {boolean} Returns `true` if `path` exists, else `false`.
+     */
+    function hasPath(object, path, hasFunc) {
+      path = castPath(path, object);
+
+      var index = -1,
+          length = path.length,
+          result = false;
+
+      while (++index < length) {
+        var key = toKey(path[index]);
+        if (!(result = object != null && hasFunc(object, key))) {
+          break;
+        }
+        object = object[key];
+      }
+      if (result || ++index != length) {
+        return result;
+      }
+      length = object == null ? 0 : object.length;
+      return !!length && isLength(length) && isIndex(key, length) &&
+        (isArray(object) || isArguments(object));
+    }
+
+    /**
+     * Initializes an array clone.
+     *
+     * @private
+     * @param {Array} array The array to clone.
+     * @returns {Array} Returns the initialized clone.
+     */
+    function initCloneArray(array) {
+      var length = array.length,
+          result = new array.constructor(length);
+
+      // Add properties assigned by `RegExp#exec`.
+      if (length && typeof array[0] == 'string' && hasOwnProperty.call(array, 'index')) {
+        result.index = array.index;
+        result.input = array.input;
+      }
+      return result;
+    }
+
+    /**
+     * Initializes an object clone.
+     *
+     * @private
+     * @param {Object} object The object to clone.
+     * @returns {Object} Returns the initialized clone.
+     */
+    function initCloneObject(object) {
+      return (typeof object.constructor == 'function' && !isPrototype(object))
+        ? baseCreate(getPrototype(object))
+        : {};
+    }
+
+    /**
+     * Initializes an object clone based on its `toStringTag`.
+     *
+     * **Note:** This function only supports cloning values with tags of
+     * `Boolean`, `Date`, `Error`, `Map`, `Number`, `RegExp`, `Set`, or `String`.
+     *
+     * @private
+     * @param {Object} object The object to clone.
+     * @param {string} tag The `toStringTag` of the object to clone.
+     * @param {boolean} [isDeep] Specify a deep clone.
+     * @returns {Object} Returns the initialized clone.
+     */
+    function initCloneByTag(object, tag, isDeep) {
+      var Ctor = object.constructor;
+      switch (tag) {
+        case arrayBufferTag:
+          return cloneArrayBuffer(object);
+
+        case boolTag:
+        case dateTag:
+          return new Ctor(+object);
+
+        case dataViewTag:
+          return cloneDataView(object, isDeep);
+
+        case float32Tag: case float64Tag:
+        case int8Tag: case int16Tag: case int32Tag:
+        case uint8Tag: case uint8ClampedTag: case uint16Tag: case uint32Tag:
+          return cloneTypedArray(object, isDeep);
+
+        case mapTag:
+          return new Ctor;
+
+        case numberTag:
+        case stringTag:
+          return new Ctor(object);
+
+        case regexpTag:
+          return cloneRegExp(object);
+
+        case setTag:
+          return new Ctor;
+
+        case symbolTag:
+          return cloneSymbol(object);
+      }
+    }
+
+    /**
+     * Inserts wrapper `details` in a comment at the top of the `source` body.
+     *
+     * @private
+     * @param {string} source The source to modify.
+     * @returns {Array} details The details to insert.
+     * @returns {string} Returns the modified source.
+     */
+    function insertWrapDetails(source, details) {
+      var length = details.length;
+      if (!length) {
+        return source;
+      }
+      var lastIndex = length - 1;
+      details[lastIndex] = (length > 1 ? '& ' : '') + details[lastIndex];
+      details = details.join(length > 2 ? ', ' : ' ');
+      return source.replace(reWrapComment, '{\n/* [wrapped with ' + details + '] */\n');
+    }
+
+    /**
+     * Checks if `value` is a flattenable `arguments` object or array.
      *
      * @private
      * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if `value` is a plain object, else `false`.
+     * @returns {boolean} Returns `true` if `value` is flattenable, else `false`.
+     */
+    function isFlattenable(value) {
+      return isArray(value) || isArguments(value) ||
+        !!(spreadableSymbol && value && value[spreadableSymbol]);
+    }
+
+    /**
+     * Checks if `value` is a valid array-like index.
+     *
+     * @private
+     * @param {*} value The value to check.
+     * @param {number} [length=MAX_SAFE_INTEGER] The upper bounds of a valid index.
+     * @returns {boolean} Returns `true` if `value` is a valid index, else `false`.
      */
-    function shimIsPlainObject(value) {
-      var ctor,
-          result;
-
-      // avoid non Object objects, `arguments` objects, and DOM elements
-      if (!(value && toString.call(value) == objectClass) ||
-          (ctor = value.constructor, isFunction(ctor) && !(ctor instanceof ctor)) ||
-          (!support.argsClass && isArguments(value)) ||
-          (!support.nodeClass && isNode(value))) {
+    function isIndex(value, length) {
+      var type = typeof value;
+      length = length == null ? MAX_SAFE_INTEGER : length;
+
+      return !!length &&
+        (type == 'number' ||
+          (type != 'symbol' && reIsUint.test(value))) &&
+            (value > -1 && value % 1 == 0 && value < length);
+    }
+
+    /**
+     * Checks if the given arguments are from an iteratee call.
+     *
+     * @private
+     * @param {*} value The potential iteratee value argument.
+     * @param {*} index The potential iteratee index or key argument.
+     * @param {*} object The potential iteratee object argument.
+     * @returns {boolean} Returns `true` if the arguments are from an iteratee call,
+     *  else `false`.
+     */
+    function isIterateeCall(value, index, object) {
+      if (!isObject(object)) {
         return false;
       }
-      // IE < 9 iterates inherited properties before own properties. If the first
-      // iterated property is an object's own property then there are no inherited
-      // enumerable properties.
-      if (support.ownLast) {
-        forIn(value, function(value, key, object) {
-          result = hasOwnProperty.call(object, key);
-          return false;
-        });
-        return result !== false;
+      var type = typeof index;
+      if (type == 'number'
+            ? (isArrayLike(object) && isIndex(index, object.length))
+            : (type == 'string' && index in object)
+          ) {
+        return eq(object[index], value);
       }
-      // In most environments an object's own properties are iterated before
-      // its inherited properties. If the last iterated property is an object's
-      // own property then there are no inherited enumerable properties.
-      forIn(value, function(value, key) {
-        result = key;
-      });
-      return typeof result == 'undefined' || hasOwnProperty.call(value, result);
+      return false;
     }
 
     /**
-     * Used by `unescape` to convert HTML entities to characters.
+     * Checks if `value` is a property name and not a property path.
      *
      * @private
-     * @param {string} match The matched character to unescape.
-     * @returns {string} Returns the unescaped character.
+     * @param {*} value The value to check.
+     * @param {Object} [object] The object to query keys on.
+     * @returns {boolean} Returns `true` if `value` is a property name, else `false`.
      */
-    function unescapeHtmlChar(match) {
-      return htmlUnescapes[match];
+    function isKey(value, object) {
+      if (isArray(value)) {
+        return false;
+      }
+      var type = typeof value;
+      if (type == 'number' || type == 'symbol' || type == 'boolean' ||
+          value == null || isSymbol(value)) {
+        return true;
+      }
+      return reIsPlainProp.test(value) || !reIsDeepProp.test(value) ||
+        (object != null && value in Object(object));
     }
 
-    /*--------------------------------------------------------------------------*/
+    /**
+     * Checks if `value` is suitable for use as unique object key.
+     *
+     * @private
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is suitable, else `false`.
+     */
+    function isKeyable(value) {
+      var type = typeof value;
+      return (type == 'string' || type == 'number' || type == 'symbol' || type == 'boolean')
+        ? (value !== '__proto__')
+        : (value === null);
+    }
 
     /**
-     * Checks if `value` is an `arguments` object.
+     * Checks if `func` has a lazy counterpart.
      *
-     * @static
-     * @memberOf _
-     * @category Objects
+     * @private
+     * @param {Function} func The function to check.
+     * @returns {boolean} Returns `true` if `func` has a lazy counterpart,
+     *  else `false`.
+     */
+    function isLaziable(func) {
+      var funcName = getFuncName(func),
+          other = lodash[funcName];
+
+      if (typeof other != 'function' || !(funcName in LazyWrapper.prototype)) {
+        return false;
+      }
+      if (func === other) {
+        return true;
+      }
+      var data = getData(other);
+      return !!data && func === data[0];
+    }
+
+    /**
+     * Checks if `func` has its source masked.
+     *
+     * @private
+     * @param {Function} func The function to check.
+     * @returns {boolean} Returns `true` if `func` is masked, else `false`.
+     */
+    function isMasked(func) {
+      return !!maskSrcKey && (maskSrcKey in func);
+    }
+
+    /**
+     * Checks if `func` is capable of being masked.
+     *
+     * @private
      * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is an `arguments` object, else `false`.
-     * @example
+     * @returns {boolean} Returns `true` if `func` is maskable, else `false`.
+     */
+    var isMaskable = coreJsData ? isFunction : stubFalse;
+
+    /**
+     * Checks if `value` is likely a prototype object.
      *
-     * (function() { return _.isArguments(arguments); })(1, 2, 3);
-     * // => true
+     * @private
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a prototype, else `false`.
+     */
+    function isPrototype(value) {
+      var Ctor = value && value.constructor,
+          proto = (typeof Ctor == 'function' && Ctor.prototype) || objectProto;
+
+      return value === proto;
+    }
+
+    /**
+     * Checks if `value` is suitable for strict equality comparisons, i.e. `===`.
      *
-     * _.isArguments([1, 2, 3]);
-     * // => false
+     * @private
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` if suitable for strict
+     *  equality comparisons, else `false`.
      */
-    function isArguments(value) {
-      return value && typeof value == 'object' && typeof value.length == 'number' &&
-        toString.call(value) == argsClass || false;
-    }
-    // fallback for browsers that can't detect `arguments` objects by [[Class]]
-    if (!support.argsClass) {
-      isArguments = function(value) {
-        return value && typeof value == 'object' && typeof value.length == 'number' &&
-          hasOwnProperty.call(value, 'callee') && !propertyIsEnumerable.call(value, 'callee') || false;
+    function isStrictComparable(value) {
+      return value === value && !isObject(value);
+    }
+
+    /**
+     * A specialized version of `matchesProperty` for source values suitable
+     * for strict equality comparisons, i.e. `===`.
+     *
+     * @private
+     * @param {string} key The key of the property to get.
+     * @param {*} srcValue The value to match.
+     * @returns {Function} Returns the new spec function.
+     */
+    function matchesStrictComparable(key, srcValue) {
+      return function(object) {
+        if (object == null) {
+          return false;
+        }
+        return object[key] === srcValue &&
+          (srcValue !== undefined || (key in Object(object)));
       };
     }
 
     /**
-     * Checks if `value` is an array.
+     * A specialized version of `_.memoize` which clears the memoized function's
+     * cache when it exceeds `MAX_MEMOIZE_SIZE`.
      *
-     * @static
-     * @memberOf _
-     * @type Function
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is an array, else `false`.
-     * @example
+     * @private
+     * @param {Function} func The function to have its output memoized.
+     * @returns {Function} Returns the new memoized function.
+     */
+    function memoizeCapped(func) {
+      var result = memoize(func, function(key) {
+        if (cache.size === MAX_MEMOIZE_SIZE) {
+          cache.clear();
+        }
+        return key;
+      });
+
+      var cache = result.cache;
+      return result;
+    }
+
+    /**
+     * Merges the function metadata of `source` into `data`.
      *
-     * (function() { return _.isArray(arguments); })();
-     * // => false
+     * Merging metadata reduces the number of wrappers used to invoke a function.
+     * This is possible because methods like `_.bind`, `_.curry`, and `_.partial`
+     * may be applied regardless of execution order. Methods like `_.ary` and
+     * `_.rearg` modify function arguments, making the order in which they are
+     * executed important, preventing the merging of metadata. However, we make
+     * an exception for a safe combined case where curried functions have `_.ary`
+     * and or `_.rearg` applied.
      *
-     * _.isArray([1, 2, 3]);
-     * // => true
+     * @private
+     * @param {Array} data The destination metadata.
+     * @param {Array} source The source metadata.
+     * @returns {Array} Returns `data`.
+     */
+    function mergeData(data, source) {
+      var bitmask = data[1],
+          srcBitmask = source[1],
+          newBitmask = bitmask | srcBitmask,
+          isCommon = newBitmask < (WRAP_BIND_FLAG | WRAP_BIND_KEY_FLAG | WRAP_ARY_FLAG);
+
+      var isCombo =
+        ((srcBitmask == WRAP_ARY_FLAG) && (bitmask == WRAP_CURRY_FLAG)) ||
+        ((srcBitmask == WRAP_ARY_FLAG) && (bitmask == WRAP_REARG_FLAG) && (data[7].length <= source[8])) ||
+        ((srcBitmask == (WRAP_ARY_FLAG | WRAP_REARG_FLAG)) && (source[7].length <= source[8]) && (bitmask == WRAP_CURRY_FLAG));
+
+      // Exit early if metadata can't be merged.
+      if (!(isCommon || isCombo)) {
+        return data;
+      }
+      // Use source `thisArg` if available.
+      if (srcBitmask & WRAP_BIND_FLAG) {
+        data[2] = source[2];
+        // Set when currying a bound function.
+        newBitmask |= bitmask & WRAP_BIND_FLAG ? 0 : WRAP_CURRY_BOUND_FLAG;
+      }
+      // Compose partial arguments.
+      var value = source[3];
+      if (value) {
+        var partials = data[3];
+        data[3] = partials ? composeArgs(partials, value, source[4]) : value;
+        data[4] = partials ? replaceHolders(data[3], PLACEHOLDER) : source[4];
+      }
+      // Compose partial right arguments.
+      value = source[5];
+      if (value) {
+        partials = data[5];
+        data[5] = partials ? composeArgsRight(partials, value, source[6]) : value;
+        data[6] = partials ? replaceHolders(data[5], PLACEHOLDER) : source[6];
+      }
+      // Use source `argPos` if available.
+      value = source[7];
+      if (value) {
+        data[7] = value;
+      }
+      // Use source `ary` if it's smaller.
+      if (srcBitmask & WRAP_ARY_FLAG) {
+        data[8] = data[8] == null ? source[8] : nativeMin(data[8], source[8]);
+      }
+      // Use source `arity` if one is not provided.
+      if (data[9] == null) {
+        data[9] = source[9];
+      }
+      // Use source `func` and merge bitmasks.
+      data[0] = source[0];
+      data[1] = newBitmask;
+
+      return data;
+    }
+
+    /**
+     * This function is like
+     * [`Object.keys`](http://ecma-international.org/ecma-262/7.0/#sec-object.keys)
+     * except that it includes inherited enumerable properties.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the array of property names.
      */
-    var isArray = nativeIsArray || function(value) {
-      return value && typeof value == 'object' && typeof value.length == 'number' &&
-        toString.call(value) == arrayClass || false;
-    };
+    function nativeKeysIn(object) {
+      var result = [];
+      if (object != null) {
+        for (var key in Object(object)) {
+          result.push(key);
+        }
+      }
+      return result;
+    }
 
     /**
-     * A fallback implementation of `Object.keys` which produces an array of the
-     * given object's own enumerable property names.
+     * Converts `value` to a string using `Object.prototype.toString`.
      *
      * @private
-     * @type Function
-     * @param {Object} object The object to inspect.
-     * @returns {Array} Returns an array of property names.
+     * @param {*} value The value to convert.
+     * @returns {string} Returns the converted string.
      */
-    var shimKeys = createIterator({
-      'args': 'object',
-      'init': '[]',
-      'top': 'if (!(objectTypes[typeof object])) return result',
-      'loop': 'result.push(index)'
-    });
+    function objectToString(value) {
+      return nativeObjectToString.call(value);
+    }
 
     /**
-     * Creates an array composed of the own enumerable property names of an object.
+     * A specialized version of `baseRest` which transforms the rest array.
      *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to inspect.
-     * @returns {Array} Returns an array of property names.
-     * @example
+     * @private
+     * @param {Function} func The function to apply a rest parameter to.
+     * @param {number} [start=func.length-1] The start position of the rest parameter.
+     * @param {Function} transform The rest array transform.
+     * @returns {Function} Returns the new function.
+     */
+    function overRest(func, start, transform) {
+      start = nativeMax(start === undefined ? (func.length - 1) : start, 0);
+      return function() {
+        var args = arguments,
+            index = -1,
+            length = nativeMax(args.length - start, 0),
+            array = Array(length);
+
+        while (++index < length) {
+          array[index] = args[start + index];
+        }
+        index = -1;
+        var otherArgs = Array(start + 1);
+        while (++index < start) {
+          otherArgs[index] = args[index];
+        }
+        otherArgs[start] = transform(array);
+        return apply(func, this, otherArgs);
+      };
+    }
+
+    /**
+     * Gets the parent value at `path` of `object`.
      *
-     * _.keys({ 'one': 1, 'two': 2, 'three': 3 });
-     * // => ['one', 'two', 'three'] (property order is not guaranteed across environments)
+     * @private
+     * @param {Object} object The object to query.
+     * @param {Array} path The path to get the parent value of.
+     * @returns {*} Returns the parent value.
      */
-    var keys = !nativeKeys ? shimKeys : function(object) {
-      if (!isObject(object)) {
-        return [];
+    function parent(object, path) {
+      return path.length < 2 ? object : baseGet(object, baseSlice(path, 0, -1));
+    }
+
+    /**
+     * Reorder `array` according to the specified indexes where the element at
+     * the first index is assigned as the first element, the element at
+     * the second index is assigned as the second element, and so on.
+     *
+     * @private
+     * @param {Array} array The array to reorder.
+     * @param {Array} indexes The arranged array indexes.
+     * @returns {Array} Returns `array`.
+     */
+    function reorder(array, indexes) {
+      var arrLength = array.length,
+          length = nativeMin(indexes.length, arrLength),
+          oldArray = copyArray(array);
+
+      while (length--) {
+        var index = indexes[length];
+        array[length] = isIndex(index, arrLength) ? oldArray[index] : undefined;
       }
-      if ((support.enumPrototypes && typeof object == 'function') ||
-          (support.nonEnumArgs && object.length && isArguments(object))) {
-        return shimKeys(object);
+      return array;
+    }
+
+    /**
+     * Gets the value at `key`, unless `key` is "__proto__" or "constructor".
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @param {string} key The key of the property to get.
+     * @returns {*} Returns the property value.
+     */
+    function safeGet(object, key) {
+      if (key === 'constructor' && typeof object[key] === 'function') {
+        return;
       }
-      return nativeKeys(object);
-    };
 
-    /** Reusable iterator options shared by `each`, `forIn`, and `forOwn` */
-    var eachIteratorOptions = {
-      'args': 'collection, callback, thisArg',
-      'top': "callback = callback && typeof thisArg == 'undefined' ? callback : baseCreateCallback(callback, thisArg, 3)",
-      'array': "typeof length == 'number'",
-      'keys': keys,
-      'loop': 'if (callback(iterable[index], index, collection) === false) return result'
-    };
+      if (key == '__proto__') {
+        return;
+      }
 
-    /** Reusable iterator options for `assign` and `defaults` */
-    var defaultsIteratorOptions = {
-      'args': 'object, source, guard',
-      'top':
-        'var args = arguments,\n' +
-        '    argsIndex = 0,\n' +
-        "    argsLength = typeof guard == 'number' ? 2 : args.length;\n" +
-        'while (++argsIndex < argsLength) {\n' +
-        '  iterable = args[argsIndex];\n' +
-        '  if (iterable && objectTypes[typeof iterable]) {',
-      'keys': keys,
-      'loop': "if (typeof result[index] == 'undefined') result[index] = iterable[index]",
-      'bottom': '  }\n}'
-    };
+      return object[key];
+    }
 
-    /** Reusable iterator options for `forIn` and `forOwn` */
-    var forOwnIteratorOptions = {
-      'top': 'if (!objectTypes[typeof iterable]) return result;\n' + eachIteratorOptions.top,
-      'array': false
-    };
+    /**
+     * Sets metadata for `func`.
+     *
+     * **Note:** If this function becomes hot, i.e. is invoked a lot in a short
+     * period of time, it will trip its breaker and transition to an identity
+     * function to avoid garbage collection pauses in V8. See
+     * [V8 issue 2070](https://bugs.chromium.org/p/v8/issues/detail?id=2070)
+     * for more details.
+     *
+     * @private
+     * @param {Function} func The function to associate metadata with.
+     * @param {*} data The metadata.
+     * @returns {Function} Returns `func`.
+     */
+    var setData = shortOut(baseSetData);
 
     /**
-     * Used to convert characters to HTML entities:
+     * A simple wrapper around the global [`setTimeout`](https://mdn.io/setTimeout).
      *
-     * Though the `>` character is escaped for symmetry, characters like `>` and `/`
-     * don't require escaping in HTML and have no special meaning unless they're part
-     * of a tag or an unquoted attribute value.
-     * http://mathiasbynens.be/notes/ambiguous-ampersands (under "semi-related fun fact")
-     */
-    var htmlEscapes = {
-      '&': '&amp;',
-      '<': '&lt;',
-      '>': '&gt;',
-      '"': '&quot;',
-      "'": '&#39;'
+     * @private
+     * @param {Function} func The function to delay.
+     * @param {number} wait The number of milliseconds to delay invocation.
+     * @returns {number|Object} Returns the timer id or timeout object.
+     */
+    var setTimeout = ctxSetTimeout || function(func, wait) {
+      return root.setTimeout(func, wait);
     };
 
-    /** Used to convert HTML entities to characters */
-    var htmlUnescapes = invert(htmlEscapes);
+    /**
+     * Sets the `toString` method of `func` to return `string`.
+     *
+     * @private
+     * @param {Function} func The function to modify.
+     * @param {Function} string The `toString` result.
+     * @returns {Function} Returns `func`.
+     */
+    var setToString = shortOut(baseSetToString);
 
-    /** Used to match HTML entities and HTML characters */
-    var reEscapedHtml = RegExp('(' + keys(htmlUnescapes).join('|') + ')', 'g'),
-        reUnescapedHtml = RegExp('[' + keys(htmlEscapes).join('') + ']', 'g');
+    /**
+     * Sets the `toString` method of `wrapper` to mimic the source of `reference`
+     * with wrapper details in a comment at the top of the source body.
+     *
+     * @private
+     * @param {Function} wrapper The function to modify.
+     * @param {Function} reference The reference function.
+     * @param {number} bitmask The bitmask flags. See `createWrap` for more details.
+     * @returns {Function} Returns `wrapper`.
+     */
+    function setWrapToString(wrapper, reference, bitmask) {
+      var source = (reference + '');
+      return setToString(wrapper, insertWrapDetails(source, updateWrapDetails(getWrapDetails(source), bitmask)));
+    }
 
     /**
-     * A function compiled to iterate `arguments` objects, arrays, objects, and
-     * strings consistenly across environments, executing the callback for each
-     * element in the collection. The callback is bound to `thisArg` and invoked
-     * with three arguments; (value, index|key, collection). Callbacks may exit
-     * iteration early by explicitly returning `false`.
+     * Creates a function that'll short out and invoke `identity` instead
+     * of `func` when it's called `HOT_COUNT` or more times in `HOT_SPAN`
+     * milliseconds.
+     *
+     * @private
+     * @param {Function} func The function to restrict.
+     * @returns {Function} Returns the new shortable function.
+     */
+    function shortOut(func) {
+      var count = 0,
+          lastCalled = 0;
+
+      return function() {
+        var stamp = nativeNow(),
+            remaining = HOT_SPAN - (stamp - lastCalled);
+
+        lastCalled = stamp;
+        if (remaining > 0) {
+          if (++count >= HOT_COUNT) {
+            return arguments[0];
+          }
+        } else {
+          count = 0;
+        }
+        return func.apply(undefined, arguments);
+      };
+    }
+
+    /**
+     * A specialized version of `_.shuffle` which mutates and sets the size of `array`.
+     *
+     * @private
+     * @param {Array} array The array to shuffle.
+     * @param {number} [size=array.length] The size of `array`.
+     * @returns {Array} Returns `array`.
+     */
+    function shuffleSelf(array, size) {
+      var index = -1,
+          length = array.length,
+          lastIndex = length - 1;
+
+      size = size === undefined ? length : size;
+      while (++index < size) {
+        var rand = baseRandom(index, lastIndex),
+            value = array[rand];
+
+        array[rand] = array[index];
+        array[index] = value;
+      }
+      array.length = size;
+      return array;
+    }
+
+    /**
+     * Converts `string` to a property path array.
+     *
+     * @private
+     * @param {string} string The string to convert.
+     * @returns {Array} Returns the property path array.
+     */
+    var stringToPath = memoizeCapped(function(string) {
+      var result = [];
+      if (string.charCodeAt(0) === 46 /* . */) {
+        result.push('');
+      }
+      string.replace(rePropName, function(match, number, quote, subString) {
+        result.push(quote ? subString.replace(reEscapeChar, '$1') : (number || match));
+      });
+      return result;
+    });
+
+    /**
+     * Converts `value` to a string key if it's not a string or symbol.
      *
      * @private
-     * @type Function
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array|Object|string} Returns `collection`.
+     * @param {*} value The value to inspect.
+     * @returns {string|symbol} Returns the key.
      */
-    var baseEach = createIterator(eachIteratorOptions);
+    function toKey(value) {
+      if (typeof value == 'string' || isSymbol(value)) {
+        return value;
+      }
+      var result = (value + '');
+      return (result == '0' && (1 / value) == -INFINITY) ? '-0' : result;
+    }
 
-    /*--------------------------------------------------------------------------*/
+    /**
+     * Converts `func` to its source code.
+     *
+     * @private
+     * @param {Function} func The function to convert.
+     * @returns {string} Returns the source code.
+     */
+    function toSource(func) {
+      if (func != null) {
+        try {
+          return funcToString.call(func);
+        } catch (e) {}
+        try {
+          return (func + '');
+        } catch (e) {}
+      }
+      return '';
+    }
 
     /**
-     * Assigns own enumerable properties of source object(s) to the destination
-     * object. Subsequent sources will overwrite property assignments of previous
-     * sources. If a callback is provided it will be executed to produce the
-     * assigned values. The callback is bound to `thisArg` and invoked with two
-     * arguments; (objectValue, sourceValue).
+     * Updates wrapper `details` based on `bitmask` flags.
+     *
+     * @private
+     * @returns {Array} details The details to modify.
+     * @param {number} bitmask The bitmask flags. See `createWrap` for more details.
+     * @returns {Array} Returns `details`.
+     */
+    function updateWrapDetails(details, bitmask) {
+      arrayEach(wrapFlags, function(pair) {
+        var value = '_.' + pair[0];
+        if ((bitmask & pair[1]) && !arrayIncludes(details, value)) {
+          details.push(value);
+        }
+      });
+      return details.sort();
+    }
+
+    /**
+     * Creates a clone of `wrapper`.
+     *
+     * @private
+     * @param {Object} wrapper The wrapper to clone.
+     * @returns {Object} Returns the cloned wrapper.
+     */
+    function wrapperClone(wrapper) {
+      if (wrapper instanceof LazyWrapper) {
+        return wrapper.clone();
+      }
+      var result = new LodashWrapper(wrapper.__wrapped__, wrapper.__chain__);
+      result.__actions__ = copyArray(wrapper.__actions__);
+      result.__index__  = wrapper.__index__;
+      result.__values__ = wrapper.__values__;
+      return result;
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates an array of elements split into groups the length of `size`.
+     * If `array` can't be split evenly, the final chunk will be the remaining
+     * elements.
      *
      * @static
      * @memberOf _
-     * @type Function
-     * @alias extend
-     * @category Objects
-     * @param {Object} object The destination object.
-     * @param {...Object} [source] The source objects.
-     * @param {Function} [callback] The function to customize assigning values.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns the destination object.
+     * @since 3.0.0
+     * @category Array
+     * @param {Array} array The array to process.
+     * @param {number} [size=1] The length of each chunk
+     * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
+     * @returns {Array} Returns the new array of chunks.
      * @example
      *
-     * _.assign({ 'name': 'fred' }, { 'employer': 'slate' });
-     * // => { 'name': 'fred', 'employer': 'slate' }
-     *
-     * var defaults = _.partialRight(_.assign, function(a, b) {
-     *   return typeof a == 'undefined' ? b : a;
-     * });
+     * _.chunk(['a', 'b', 'c', 'd'], 2);
+     * // => [['a', 'b'], ['c', 'd']]
      *
-     * var object = { 'name': 'barney' };
-     * defaults(object, { 'name': 'fred', 'employer': 'slate' });
-     * // => { 'name': 'barney', 'employer': 'slate' }
+     * _.chunk(['a', 'b', 'c', 'd'], 3);
+     * // => [['a', 'b', 'c'], ['d']]
      */
-    var assign = createIterator(defaultsIteratorOptions, {
-      'top':
-        defaultsIteratorOptions.top.replace(';',
-          ';\n' +
-          "if (argsLength > 3 && typeof args[argsLength - 2] == 'function') {\n" +
-          '  var callback = baseCreateCallback(args[--argsLength - 1], args[argsLength--], 2);\n' +
-          "} else if (argsLength > 2 && typeof args[argsLength - 1] == 'function') {\n" +
-          '  callback = args[--argsLength];\n' +
-          '}'
-        ),
-      'loop': 'result[index] = callback ? callback(result[index], iterable[index]) : iterable[index]'
-    });
+    function chunk(array, size, guard) {
+      if ((guard ? isIterateeCall(array, size, guard) : size === undefined)) {
+        size = 1;
+      } else {
+        size = nativeMax(toInteger(size), 0);
+      }
+      var length = array == null ? 0 : array.length;
+      if (!length || size < 1) {
+        return [];
+      }
+      var index = 0,
+          resIndex = 0,
+          result = Array(nativeCeil(length / size));
+
+      while (index < length) {
+        result[resIndex++] = baseSlice(array, index, (index += size));
+      }
+      return result;
+    }
 
     /**
-     * Creates a clone of `value`. If `isDeep` is `true` nested objects will also
-     * be cloned, otherwise they will be assigned by reference. If a callback
-     * is provided it will be executed to produce the cloned values. If the
-     * callback returns `undefined` cloning will be handled by the method instead.
-     * The callback is bound to `thisArg` and invoked with one argument; (value).
+     * Creates an array with all falsey values removed. The values `false`, `null`,
+     * `0`, `""`, `undefined`, and `NaN` are falsey.
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {*} value The value to clone.
-     * @param {boolean} [isDeep=false] Specify a deep clone.
-     * @param {Function} [callback] The function to customize cloning values.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the cloned value.
+     * @since 0.1.0
+     * @category Array
+     * @param {Array} array The array to compact.
+     * @returns {Array} Returns the new array of filtered values.
      * @example
      *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
-     * ];
+     * _.compact([0, 1, false, 2, '', 3]);
+     * // => [1, 2, 3]
+     */
+    function compact(array) {
+      var index = -1,
+          length = array == null ? 0 : array.length,
+          resIndex = 0,
+          result = [];
+
+      while (++index < length) {
+        var value = array[index];
+        if (value) {
+          result[resIndex++] = value;
+        }
+      }
+      return result;
+    }
+
+    /**
+     * Creates a new array concatenating `array` with any additional arrays
+     * and/or values.
      *
-     * var shallow = _.clone(characters);
-     * shallow[0] === characters[0];
-     * // => true
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Array
+     * @param {Array} array The array to concatenate.
+     * @param {...*} [values] The values to concatenate.
+     * @returns {Array} Returns the new concatenated array.
+     * @example
      *
-     * var deep = _.clone(characters, true);
-     * deep[0] === characters[0];
-     * // => false
+     * var array = [1];
+     * var other = _.concat(array, 2, [3], [[4]]);
      *
-     * _.mixin({
-     *   'clone': _.partialRight(_.clone, function(value) {
-     *     return _.isElement(value) ? value.cloneNode(false) : undefined;
-     *   })
-     * });
+     * console.log(other);
+     * // => [1, 2, 3, [4]]
      *
-     * var clone = _.clone(document.body);
-     * clone.childNodes.length;
-     * // => 0
+     * console.log(array);
+     * // => [1]
      */
-    function clone(value, isDeep, callback, thisArg) {
-      // allows working with "Collections" methods without using their `index`
-      // and `collection` arguments for `isDeep` and `callback`
-      if (typeof isDeep != 'boolean' && isDeep != null) {
-        thisArg = callback;
-        callback = isDeep;
-        isDeep = false;
+    function concat() {
+      var length = arguments.length;
+      if (!length) {
+        return [];
       }
-      return baseClone(value, isDeep, typeof callback == 'function' && baseCreateCallback(callback, thisArg, 1));
+      var args = Array(length - 1),
+          array = arguments[0],
+          index = length;
+
+      while (index--) {
+        args[index - 1] = arguments[index];
+      }
+      return arrayPush(isArray(array) ? copyArray(array) : [array], baseFlatten(args, 1));
     }
 
     /**
-     * Creates a deep clone of `value`. If a callback is provided it will be
-     * executed to produce the cloned values. If the callback returns `undefined`
-     * cloning will be handled by the method instead. The callback is bound to
-     * `thisArg` and invoked with one argument; (value).
+     * Creates an array of `array` values not included in the other given arrays
+     * using [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
+     * for equality comparisons. The order and references of result values are
+     * determined by the first array.
      *
-     * Note: This method is loosely based on the structured clone algorithm. Functions
-     * and DOM nodes are **not** cloned. The enumerable properties of `arguments` objects and
-     * objects created by constructors other than `Object` are cloned to plain `Object` objects.
-     * See http://www.w3.org/TR/html5/infrastructure.html#internal-structured-cloning-algorithm.
+     * **Note:** Unlike `_.pullAll`, this method returns a new array.
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {*} value The value to deep clone.
-     * @param {Function} [callback] The function to customize cloning values.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the deep cloned value.
+     * @since 0.1.0
+     * @category Array
+     * @param {Array} array The array to inspect.
+     * @param {...Array} [values] The values to exclude.
+     * @returns {Array} Returns the new array of filtered values.
+     * @see _.without, _.xor
      * @example
      *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
-     * ];
+     * _.difference([2, 1], [2, 3]);
+     * // => [1]
+     */
+    var difference = baseRest(function(array, values) {
+      return isArrayLikeObject(array)
+        ? baseDifference(array, baseFlatten(values, 1, isArrayLikeObject, true))
+        : [];
+    });
+
+    /**
+     * This method is like `_.difference` except that it accepts `iteratee` which
+     * is invoked for each element of `array` and `values` to generate the criterion
+     * by which they're compared. The order and references of result values are
+     * determined by the first array. The iteratee is invoked with one argument:
+     * (value).
      *
-     * var deep = _.cloneDeep(characters);
-     * deep[0] === characters[0];
-     * // => false
+     * **Note:** Unlike `_.pullAllBy`, this method returns a new array.
      *
-     * var view = {
-     *   'label': 'docs',
-     *   'node': element
-     * };
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Array
+     * @param {Array} array The array to inspect.
+     * @param {...Array} [values] The values to exclude.
+     * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+     * @returns {Array} Returns the new array of filtered values.
+     * @example
+     *
+     * _.differenceBy([2.1, 1.2], [2.3, 3.4], Math.floor);
+     * // => [1.2]
+     *
+     * // The `_.property` iteratee shorthand.
+     * _.differenceBy([{ 'x': 2 }, { 'x': 1 }], [{ 'x': 1 }], 'x');
+     * // => [{ 'x': 2 }]
+     */
+    var differenceBy = baseRest(function(array, values) {
+      var iteratee = last(values);
+      if (isArrayLikeObject(iteratee)) {
+        iteratee = undefined;
+      }
+      return isArrayLikeObject(array)
+        ? baseDifference(array, baseFlatten(values, 1, isArrayLikeObject, true), getIteratee(iteratee, 2))
+        : [];
+    });
+
+    /**
+     * This method is like `_.difference` except that it accepts `comparator`
+     * which is invoked to compare elements of `array` to `values`. The order and
+     * references of result values are determined by the first array. The comparator
+     * is invoked with two arguments: (arrVal, othVal).
      *
-     * var clone = _.cloneDeep(view, function(value) {
-     *   return _.isElement(value) ? value.cloneNode(true) : undefined;
-     * });
+     * **Note:** Unlike `_.pullAllWith`, this method returns a new array.
      *
-     * clone.node == view.node;
-     * // => false
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Array
+     * @param {Array} array The array to inspect.
+     * @param {...Array} [values] The values to exclude.
+     * @param {Function} [comparator] The comparator invoked per element.
+     * @returns {Array} Returns the new array of filtered values.
+     * @example
+     *
+     * var objects = [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }];
+     *
+     * _.differenceWith(objects, [{ 'x': 1, 'y': 2 }], _.isEqual);
+     * // => [{ 'x': 2, 'y': 1 }]
      */
-    function cloneDeep(value, callback, thisArg) {
-      return baseClone(value, true, typeof callback == 'function' && baseCreateCallback(callback, thisArg, 1));
-    }
+    var differenceWith = baseRest(function(array, values) {
+      var comparator = last(values);
+      if (isArrayLikeObject(comparator)) {
+        comparator = undefined;
+      }
+      return isArrayLikeObject(array)
+        ? baseDifference(array, baseFlatten(values, 1, isArrayLikeObject, true), undefined, comparator)
+        : [];
+    });
 
     /**
-     * Creates an object that inherits from the given `prototype` object. If a
-     * `properties` object is provided its own enumerable properties are assigned
-     * to the created object.
+     * Creates a slice of `array` with `n` elements dropped from the beginning.
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {Object} prototype The object to inherit from.
-     * @param {Object} [properties] The properties to assign to the object.
-     * @returns {Object} Returns the new object.
+     * @since 0.5.0
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {number} [n=1] The number of elements to drop.
+     * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
+     * @returns {Array} Returns the slice of `array`.
      * @example
      *
-     * function Shape() {
-     *   this.x = 0;
-     *   this.y = 0;
-     * }
-     *
-     * function Circle() {
-     *   Shape.call(this);
-     * }
+     * _.drop([1, 2, 3]);
+     * // => [2, 3]
      *
-     * Circle.prototype = _.create(Shape.prototype, { 'constructor': Circle });
+     * _.drop([1, 2, 3], 2);
+     * // => [3]
      *
-     * var circle = new Circle;
-     * circle instanceof Circle;
-     * // => true
+     * _.drop([1, 2, 3], 5);
+     * // => []
      *
-     * circle instanceof Shape;
-     * // => true
+     * _.drop([1, 2, 3], 0);
+     * // => [1, 2, 3]
      */
-    function create(prototype, properties) {
-      var result = baseCreate(prototype);
-      return properties ? assign(result, properties) : result;
+    function drop(array, n, guard) {
+      var length = array == null ? 0 : array.length;
+      if (!length) {
+        return [];
+      }
+      n = (guard || n === undefined) ? 1 : toInteger(n);
+      return baseSlice(array, n < 0 ? 0 : n, length);
     }
 
     /**
-     * Assigns own enumerable properties of source object(s) to the destination
-     * object for all destination properties that resolve to `undefined`. Once a
-     * property is set, additional defaults of the same property will be ignored.
+     * Creates a slice of `array` with `n` elements dropped from the end.
      *
      * @static
      * @memberOf _
-     * @type Function
-     * @category Objects
-     * @param {Object} object The destination object.
-     * @param {...Object} [source] The source objects.
-     * @param- {Object} [guard] Allows working with `_.reduce` without using its
-     *  `key` and `object` arguments as sources.
-     * @returns {Object} Returns the destination object.
+     * @since 3.0.0
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {number} [n=1] The number of elements to drop.
+     * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
+     * @returns {Array} Returns the slice of `array`.
      * @example
      *
-     * var object = { 'name': 'barney' };
-     * _.defaults(object, { 'name': 'fred', 'employer': 'slate' });
-     * // => { 'name': 'barney', 'employer': 'slate' }
+     * _.dropRight([1, 2, 3]);
+     * // => [1, 2]
+     *
+     * _.dropRight([1, 2, 3], 2);
+     * // => [1]
+     *
+     * _.dropRight([1, 2, 3], 5);
+     * // => []
+     *
+     * _.dropRight([1, 2, 3], 0);
+     * // => [1, 2, 3]
      */
-    var defaults = createIterator(defaultsIteratorOptions);
+    function dropRight(array, n, guard) {
+      var length = array == null ? 0 : array.length;
+      if (!length) {
+        return [];
+      }
+      n = (guard || n === undefined) ? 1 : toInteger(n);
+      n = length - n;
+      return baseSlice(array, 0, n < 0 ? 0 : n);
+    }
 
     /**
-     * This method is like `_.findIndex` except that it returns the key of the
-     * first element that passes the callback check, instead of the element itself.
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * Creates a slice of `array` excluding elements dropped from the end.
+     * Elements are dropped until `predicate` returns falsey. The predicate is
+     * invoked with three arguments: (value, index, array).
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to search.
-     * @param {Function|Object|string} [callback=identity] The function called per
-     *  iteration. If a property name or object is provided it will be used to
-     *  create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {string|undefined} Returns the key of the found element, else `undefined`.
+     * @since 3.0.0
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {Function} [predicate=_.identity] The function invoked per iteration.
+     * @returns {Array} Returns the slice of `array`.
      * @example
      *
-     * var characters = {
-     *   'barney': {  'age': 36, 'blocked': false },
-     *   'fred': {    'age': 40, 'blocked': true },
-     *   'pebbles': { 'age': 1,  'blocked': false }
-     * };
+     * var users = [
+     *   { 'user': 'barney',  'active': true },
+     *   { 'user': 'fred',    'active': false },
+     *   { 'user': 'pebbles', 'active': false }
+     * ];
      *
-     * _.findKey(characters, function(chr) {
-     *   return chr.age < 40;
-     * });
-     * // => 'barney' (property order is not guaranteed across environments)
+     * _.dropRightWhile(users, function(o) { return !o.active; });
+     * // => objects for ['barney']
      *
-     * // using "_.where" callback shorthand
-     * _.findKey(characters, { 'age': 1 });
-     * // => 'pebbles'
+     * // The `_.matches` iteratee shorthand.
+     * _.dropRightWhile(users, { 'user': 'pebbles', 'active': false });
+     * // => objects for ['barney', 'fred']
      *
-     * // using "_.pluck" callback shorthand
-     * _.findKey(characters, 'blocked');
-     * // => 'fred'
+     * // The `_.matchesProperty` iteratee shorthand.
+     * _.dropRightWhile(users, ['active', false]);
+     * // => objects for ['barney']
+     *
+     * // The `_.property` iteratee shorthand.
+     * _.dropRightWhile(users, 'active');
+     * // => objects for ['barney', 'fred', 'pebbles']
      */
-    function findKey(object, callback, thisArg) {
-      var result;
-      callback = lodash.createCallback(callback, thisArg, 3);
-      forOwn(object, function(value, key, object) {
-        if (callback(value, key, object)) {
-          result = key;
-          return false;
-        }
-      });
-      return result;
+    function dropRightWhile(array, predicate) {
+      return (array && array.length)
+        ? baseWhile(array, getIteratee(predicate, 3), true, true)
+        : [];
     }
 
     /**
-     * This method is like `_.findKey` except that it iterates over elements
-     * of a `collection` in the opposite order.
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * Creates a slice of `array` excluding elements dropped from the beginning.
+     * Elements are dropped until `predicate` returns falsey. The predicate is
+     * invoked with three arguments: (value, index, array).
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to search.
-     * @param {Function|Object|string} [callback=identity] The function called per
-     *  iteration. If a property name or object is provided it will be used to
-     *  create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {string|undefined} Returns the key of the found element, else `undefined`.
+     * @since 3.0.0
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {Function} [predicate=_.identity] The function invoked per iteration.
+     * @returns {Array} Returns the slice of `array`.
      * @example
      *
-     * var characters = {
-     *   'barney': {  'age': 36, 'blocked': true },
-     *   'fred': {    'age': 40, 'blocked': false },
-     *   'pebbles': { 'age': 1,  'blocked': true }
-     * };
+     * var users = [
+     *   { 'user': 'barney',  'active': false },
+     *   { 'user': 'fred',    'active': false },
+     *   { 'user': 'pebbles', 'active': true }
+     * ];
      *
-     * _.findLastKey(characters, function(chr) {
-     *   return chr.age < 40;
-     * });
-     * // => returns `pebbles`, assuming `_.findKey` returns `barney`
+     * _.dropWhile(users, function(o) { return !o.active; });
+     * // => objects for ['pebbles']
      *
-     * // using "_.where" callback shorthand
-     * _.findLastKey(characters, { 'age': 40 });
-     * // => 'fred'
+     * // The `_.matches` iteratee shorthand.
+     * _.dropWhile(users, { 'user': 'barney', 'active': false });
+     * // => objects for ['fred', 'pebbles']
      *
-     * // using "_.pluck" callback shorthand
-     * _.findLastKey(characters, 'blocked');
-     * // => 'pebbles'
+     * // The `_.matchesProperty` iteratee shorthand.
+     * _.dropWhile(users, ['active', false]);
+     * // => objects for ['pebbles']
+     *
+     * // The `_.property` iteratee shorthand.
+     * _.dropWhile(users, 'active');
+     * // => objects for ['barney', 'fred', 'pebbles']
      */
-    function findLastKey(object, callback, thisArg) {
-      var result;
-      callback = lodash.createCallback(callback, thisArg, 3);
-      forOwnRight(object, function(value, key, object) {
-        if (callback(value, key, object)) {
-          result = key;
-          return false;
-        }
-      });
-      return result;
+    function dropWhile(array, predicate) {
+      return (array && array.length)
+        ? baseWhile(array, getIteratee(predicate, 3), true)
+        : [];
     }
 
     /**
-     * Iterates over own and inherited enumerable properties of an object,
-     * executing the callback for each property. The callback is bound to `thisArg`
-     * and invoked with three arguments; (value, key, object). Callbacks may exit
-     * iteration early by explicitly returning `false`.
+     * Fills elements of `array` with `value` from `start` up to, but not
+     * including, `end`.
+     *
+     * **Note:** This method mutates `array`.
      *
      * @static
      * @memberOf _
-     * @type Function
-     * @category Objects
-     * @param {Object} object The object to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns `object`.
+     * @since 3.2.0
+     * @category Array
+     * @param {Array} array The array to fill.
+     * @param {*} value The value to fill `array` with.
+     * @param {number} [start=0] The start position.
+     * @param {number} [end=array.length] The end position.
+     * @returns {Array} Returns `array`.
      * @example
      *
-     * function Shape() {
-     *   this.x = 0;
-     *   this.y = 0;
-     * }
+     * var array = [1, 2, 3];
      *
-     * Shape.prototype.move = function(x, y) {
-     *   this.x += x;
-     *   this.y += y;
-     * };
+     * _.fill(array, 'a');
+     * console.log(array);
+     * // => ['a', 'a', 'a']
      *
-     * _.forIn(new Shape, function(value, key) {
-     *   console.log(key);
-     * });
-     * // => logs 'x', 'y', and 'move' (property order is not guaranteed across environments)
+     * _.fill(Array(3), 2);
+     * // => [2, 2, 2]
+     *
+     * _.fill([4, 6, 8, 10], '*', 1, 3);
+     * // => [4, '*', '*', 10]
      */
-    var forIn = createIterator(eachIteratorOptions, forOwnIteratorOptions, {
-      'useHas': false
-    });
+    function fill(array, value, start, end) {
+      var length = array == null ? 0 : array.length;
+      if (!length) {
+        return [];
+      }
+      if (start && typeof start != 'number' && isIterateeCall(array, value, start)) {
+        start = 0;
+        end = length;
+      }
+      return baseFill(array, value, start, end);
+    }
 
     /**
-     * This method is like `_.forIn` except that it iterates over elements
-     * of a `collection` in the opposite order.
+     * This method is like `_.find` except that it returns the index of the first
+     * element `predicate` returns truthy for instead of the element itself.
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns `object`.
+     * @since 1.1.0
+     * @category Array
+     * @param {Array} array The array to inspect.
+     * @param {Function} [predicate=_.identity] The function invoked per iteration.
+     * @param {number} [fromIndex=0] The index to search from.
+     * @returns {number} Returns the index of the found element, else `-1`.
      * @example
      *
-     * function Shape() {
-     *   this.x = 0;
-     *   this.y = 0;
-     * }
+     * var users = [
+     *   { 'user': 'barney',  'active': false },
+     *   { 'user': 'fred',    'active': false },
+     *   { 'user': 'pebbles', 'active': true }
+     * ];
      *
-     * Shape.prototype.move = function(x, y) {
-     *   this.x += x;
-     *   this.y += y;
-     * };
+     * _.findIndex(users, function(o) { return o.user == 'barney'; });
+     * // => 0
      *
-     * _.forInRight(new Shape, function(value, key) {
-     *   console.log(key);
-     * });
-     * // => logs 'move', 'y', and 'x' assuming `_.forIn ` logs 'x', 'y', and 'move'
+     * // The `_.matches` iteratee shorthand.
+     * _.findIndex(users, { 'user': 'fred', 'active': false });
+     * // => 1
+     *
+     * // The `_.matchesProperty` iteratee shorthand.
+     * _.findIndex(users, ['active', false]);
+     * // => 0
+     *
+     * // The `_.property` iteratee shorthand.
+     * _.findIndex(users, 'active');
+     * // => 2
      */
-    function forInRight(object, callback, thisArg) {
-      var pairs = [];
-
-      forIn(object, function(value, key) {
-        pairs.push(key, value);
-      });
-
-      var length = pairs.length;
-      callback = baseCreateCallback(callback, thisArg, 3);
-      while (length--) {
-        if (callback(pairs[length--], pairs[length], object) === false) {
-          break;
-        }
+    function findIndex(array, predicate, fromIndex) {
+      var length = array == null ? 0 : array.length;
+      if (!length) {
+        return -1;
+      }
+      var index = fromIndex == null ? 0 : toInteger(fromIndex);
+      if (index < 0) {
+        index = nativeMax(length + index, 0);
       }
-      return object;
+      return baseFindIndex(array, getIteratee(predicate, 3), index);
     }
 
     /**
-     * Iterates over own enumerable properties of an object, executing the callback
-     * for each property. The callback is bound to `thisArg` and invoked with three
-     * arguments; (value, key, object). Callbacks may exit iteration early by
-     * explicitly returning `false`.
+     * This method is like `_.findIndex` except that it iterates over elements
+     * of `collection` from right to left.
      *
      * @static
      * @memberOf _
-     * @type Function
-     * @category Objects
-     * @param {Object} object The object to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns `object`.
+     * @since 2.0.0
+     * @category Array
+     * @param {Array} array The array to inspect.
+     * @param {Function} [predicate=_.identity] The function invoked per iteration.
+     * @param {number} [fromIndex=array.length-1] The index to search from.
+     * @returns {number} Returns the index of the found element, else `-1`.
      * @example
      *
-     * _.forOwn({ '0': 'zero', '1': 'one', 'length': 2 }, function(num, key) {
-     *   console.log(key);
-     * });
-     * // => logs '0', '1', and 'length' (property order is not guaranteed across environments)
+     * var users = [
+     *   { 'user': 'barney',  'active': true },
+     *   { 'user': 'fred',    'active': false },
+     *   { 'user': 'pebbles', 'active': false }
+     * ];
+     *
+     * _.findLastIndex(users, function(o) { return o.user == 'pebbles'; });
+     * // => 2
+     *
+     * // The `_.matches` iteratee shorthand.
+     * _.findLastIndex(users, { 'user': 'barney', 'active': true });
+     * // => 0
+     *
+     * // The `_.matchesProperty` iteratee shorthand.
+     * _.findLastIndex(users, ['active', false]);
+     * // => 2
+     *
+     * // The `_.property` iteratee shorthand.
+     * _.findLastIndex(users, 'active');
+     * // => 0
      */
-    var forOwn = createIterator(eachIteratorOptions, forOwnIteratorOptions);
+    function findLastIndex(array, predicate, fromIndex) {
+      var length = array == null ? 0 : array.length;
+      if (!length) {
+        return -1;
+      }
+      var index = length - 1;
+      if (fromIndex !== undefined) {
+        index = toInteger(fromIndex);
+        index = fromIndex < 0
+          ? nativeMax(length + index, 0)
+          : nativeMin(index, length - 1);
+      }
+      return baseFindIndex(array, getIteratee(predicate, 3), index, true);
+    }
 
     /**
-     * This method is like `_.forOwn` except that it iterates over elements
-     * of a `collection` in the opposite order.
+     * Flattens `array` a single level deep.
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns `object`.
+     * @since 0.1.0
+     * @category Array
+     * @param {Array} array The array to flatten.
+     * @returns {Array} Returns the new flattened array.
      * @example
      *
-     * _.forOwnRight({ '0': 'zero', '1': 'one', 'length': 2 }, function(num, key) {
-     *   console.log(key);
-     * });
-     * // => logs 'length', '1', and '0' assuming `_.forOwn` logs '0', '1', and 'length'
+     * _.flatten([1, [2, [3, [4]], 5]]);
+     * // => [1, 2, [3, [4]], 5]
      */
-    function forOwnRight(object, callback, thisArg) {
-      var props = keys(object),
-          length = props.length;
-
-      callback = baseCreateCallback(callback, thisArg, 3);
-      while (length--) {
-        var key = props[length];
-        if (callback(object[key], key, object) === false) {
-          break;
-        }
-      }
-      return object;
+    function flatten(array) {
+      var length = array == null ? 0 : array.length;
+      return length ? baseFlatten(array, 1) : [];
     }
 
     /**
-     * Creates a sorted array of property names of all enumerable properties,
-     * own and inherited, of `object` that have function values.
+     * Recursively flattens `array`.
      *
      * @static
      * @memberOf _
-     * @alias methods
-     * @category Objects
-     * @param {Object} object The object to inspect.
-     * @returns {Array} Returns an array of property names that have function values.
+     * @since 3.0.0
+     * @category Array
+     * @param {Array} array The array to flatten.
+     * @returns {Array} Returns the new flattened array.
      * @example
      *
-     * _.functions(_);
-     * // => ['all', 'any', 'bind', 'bindAll', 'clone', 'compact', 'compose', ...]
+     * _.flattenDeep([1, [2, [3, [4]], 5]]);
+     * // => [1, 2, 3, 4, 5]
      */
-    function functions(object) {
-      var result = [];
-      forIn(object, function(value, key) {
-        if (isFunction(value)) {
-          result.push(key);
-        }
-      });
-      return result.sort();
+    function flattenDeep(array) {
+      var length = array == null ? 0 : array.length;
+      return length ? baseFlatten(array, INFINITY) : [];
     }
 
     /**
-     * Checks if the specified property name exists as a direct property of `object`,
-     * instead of an inherited property.
+     * Recursively flatten `array` up to `depth` times.
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to inspect.
-     * @param {string} key The name of the property to check.
-     * @returns {boolean} Returns `true` if key is a direct property, else `false`.
+     * @since 4.4.0
+     * @category Array
+     * @param {Array} array The array to flatten.
+     * @param {number} [depth=1] The maximum recursion depth.
+     * @returns {Array} Returns the new flattened array.
      * @example
      *
-     * _.has({ 'a': 1, 'b': 2, 'c': 3 }, 'b');
-     * // => true
+     * var array = [1, [2, [3, [4]], 5]];
+     *
+     * _.flattenDepth(array, 1);
+     * // => [1, 2, [3, [4]], 5]
+     *
+     * _.flattenDepth(array, 2);
+     * // => [1, 2, 3, [4], 5]
      */
-    function has(object, key) {
-      return object ? hasOwnProperty.call(object, key) : false;
+    function flattenDepth(array, depth) {
+      var length = array == null ? 0 : array.length;
+      if (!length) {
+        return [];
+      }
+      depth = depth === undefined ? 1 : toInteger(depth);
+      return baseFlatten(array, depth);
     }
 
     /**
-     * Creates an object composed of the inverted keys and values of the given object.
+     * The inverse of `_.toPairs`; this method returns an object composed
+     * from key-value `pairs`.
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to invert.
-     * @returns {Object} Returns the created inverted object.
+     * @since 4.0.0
+     * @category Array
+     * @param {Array} pairs The key-value pairs.
+     * @returns {Object} Returns the new object.
      * @example
      *
-     * _.invert({ 'first': 'fred', 'second': 'barney' });
-     * // => { 'fred': 'first', 'barney': 'second' }
+     * _.fromPairs([['a', 1], ['b', 2]]);
+     * // => { 'a': 1, 'b': 2 }
      */
-    function invert(object) {
+    function fromPairs(pairs) {
       var index = -1,
-          props = keys(object),
-          length = props.length,
+          length = pairs == null ? 0 : pairs.length,
           result = {};
 
       while (++index < length) {
-        var key = props[index];
-        result[object[key]] = key;
+        var pair = pairs[index];
+        result[pair[0]] = pair[1];
       }
       return result;
     }
 
     /**
-     * Checks if `value` is a boolean value.
+     * Gets the first element of `array`.
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a boolean value, else `false`.
+     * @since 0.1.0
+     * @alias first
+     * @category Array
+     * @param {Array} array The array to query.
+     * @returns {*} Returns the first element of `array`.
      * @example
      *
-     * _.isBoolean(null);
-     * // => false
+     * _.head([1, 2, 3]);
+     * // => 1
+     *
+     * _.head([]);
+     * // => undefined
      */
-    function isBoolean(value) {
-      return value === true || value === false ||
-        value && typeof value == 'object' && toString.call(value) == boolClass || false;
+    function head(array) {
+      return (array && array.length) ? array[0] : undefined;
     }
 
     /**
-     * Checks if `value` is a date.
+     * Gets the index at which the first occurrence of `value` is found in `array`
+     * using [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
+     * for equality comparisons. If `fromIndex` is negative, it's used as the
+     * offset from the end of `array`.
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a date, else `false`.
+     * @since 0.1.0
+     * @category Array
+     * @param {Array} array The array to inspect.
+     * @param {*} value The value to search for.
+     * @param {number} [fromIndex=0] The index to search from.
+     * @returns {number} Returns the index of the matched value, else `-1`.
      * @example
      *
-     * _.isDate(new Date);
-     * // => true
+     * _.indexOf([1, 2, 1, 2], 2);
+     * // => 1
+     *
+     * // Search from the `fromIndex`.
+     * _.indexOf([1, 2, 1, 2], 2, 2);
+     * // => 3
      */
-    function isDate(value) {
-      return value && typeof value == 'object' && toString.call(value) == dateClass || false;
+    function indexOf(array, value, fromIndex) {
+      var length = array == null ? 0 : array.length;
+      if (!length) {
+        return -1;
+      }
+      var index = fromIndex == null ? 0 : toInteger(fromIndex);
+      if (index < 0) {
+        index = nativeMax(length + index, 0);
+      }
+      return baseIndexOf(array, value, index);
     }
 
     /**
-     * Checks if `value` is a DOM element.
+     * Gets all but the last element of `array`.
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a DOM element, else `false`.
+     * @since 0.1.0
+     * @category Array
+     * @param {Array} array The array to query.
+     * @returns {Array} Returns the slice of `array`.
      * @example
      *
-     * _.isElement(document.body);
-     * // => true
+     * _.initial([1, 2, 3]);
+     * // => [1, 2]
      */
-    function isElement(value) {
-      return value && value.nodeType === 1 || false;
+    function initial(array) {
+      var length = array == null ? 0 : array.length;
+      return length ? baseSlice(array, 0, -1) : [];
     }
 
     /**
-     * Checks if `value` is empty. Arrays, strings, or `arguments` objects with a
-     * length of `0` and objects with no own enumerable properties are considered
-     * "empty".
+     * Creates an array of unique values that are included in all given arrays
+     * using [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
+     * for equality comparisons. The order and references of result values are
+     * determined by the first array.
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {Array|Object|string} value The value to inspect.
-     * @returns {boolean} Returns `true` if the `value` is empty, else `false`.
+     * @since 0.1.0
+     * @category Array
+     * @param {...Array} [arrays] The arrays to inspect.
+     * @returns {Array} Returns the new array of intersecting values.
      * @example
      *
-     * _.isEmpty([1, 2, 3]);
-     * // => false
+     * _.intersection([2, 1], [2, 3]);
+     * // => [2]
+     */
+    var intersection = baseRest(function(arrays) {
+      var mapped = arrayMap(arrays, castArrayLikeObject);
+      return (mapped.length && mapped[0] === arrays[0])
+        ? baseIntersection(mapped)
+        : [];
+    });
+
+    /**
+     * This method is like `_.intersection` except that it accepts `iteratee`
+     * which is invoked for each element of each `arrays` to generate the criterion
+     * by which they're compared. The order and references of result values are
+     * determined by the first array. The iteratee is invoked with one argument:
+     * (value).
      *
-     * _.isEmpty({});
-     * // => true
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Array
+     * @param {...Array} [arrays] The arrays to inspect.
+     * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+     * @returns {Array} Returns the new array of intersecting values.
+     * @example
      *
-     * _.isEmpty('');
-     * // => true
+     * _.intersectionBy([2.1, 1.2], [2.3, 3.4], Math.floor);
+     * // => [2.1]
+     *
+     * // The `_.property` iteratee shorthand.
+     * _.intersectionBy([{ 'x': 1 }], [{ 'x': 2 }, { 'x': 1 }], 'x');
+     * // => [{ 'x': 1 }]
      */
-    function isEmpty(value) {
-      var result = true;
-      if (!value) {
-        return result;
+    var intersectionBy = baseRest(function(arrays) {
+      var iteratee = last(arrays),
+          mapped = arrayMap(arrays, castArrayLikeObject);
+
+      if (iteratee === last(mapped)) {
+        iteratee = undefined;
+      } else {
+        mapped.pop();
       }
-      var className = toString.call(value),
-          length = value.length;
+      return (mapped.length && mapped[0] === arrays[0])
+        ? baseIntersection(mapped, getIteratee(iteratee, 2))
+        : [];
+    });
 
-      if ((className == arrayClass || className == stringClass ||
-          (support.argsClass ? className == argsClass : isArguments(value))) ||
-          (className == objectClass && typeof length == 'number' && isFunction(value.splice))) {
-        return !length;
+    /**
+     * This method is like `_.intersection` except that it accepts `comparator`
+     * which is invoked to compare elements of `arrays`. The order and references
+     * of result values are determined by the first array. The comparator is
+     * invoked with two arguments: (arrVal, othVal).
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Array
+     * @param {...Array} [arrays] The arrays to inspect.
+     * @param {Function} [comparator] The comparator invoked per element.
+     * @returns {Array} Returns the new array of intersecting values.
+     * @example
+     *
+     * var objects = [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }];
+     * var others = [{ 'x': 1, 'y': 1 }, { 'x': 1, 'y': 2 }];
+     *
+     * _.intersectionWith(objects, others, _.isEqual);
+     * // => [{ 'x': 1, 'y': 2 }]
+     */
+    var intersectionWith = baseRest(function(arrays) {
+      var comparator = last(arrays),
+          mapped = arrayMap(arrays, castArrayLikeObject);
+
+      comparator = typeof comparator == 'function' ? comparator : undefined;
+      if (comparator) {
+        mapped.pop();
       }
-      forOwn(value, function() {
-        return (result = false);
-      });
-      return result;
+      return (mapped.length && mapped[0] === arrays[0])
+        ? baseIntersection(mapped, undefined, comparator)
+        : [];
+    });
+
+    /**
+     * Converts all elements in `array` into a string separated by `separator`.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Array
+     * @param {Array} array The array to convert.
+     * @param {string} [separator=','] The element separator.
+     * @returns {string} Returns the joined string.
+     * @example
+     *
+     * _.join(['a', 'b', 'c'], '~');
+     * // => 'a~b~c'
+     */
+    function join(array, separator) {
+      return array == null ? '' : nativeJoin.call(array, separator);
     }
 
     /**
-     * Performs a deep comparison between two values to determine if they are
-     * equivalent to each other. If a callback is provided it will be executed
-     * to compare values. If the callback returns `undefined` comparisons will
-     * be handled by the method instead. The callback is bound to `thisArg` and
-     * invoked with two arguments; (a, b).
+     * Gets the last element of `array`.
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {*} a The value to compare.
-     * @param {*} b The other value to compare.
-     * @param {Function} [callback] The function to customize comparing values.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
+     * @since 0.1.0
+     * @category Array
+     * @param {Array} array The array to query.
+     * @returns {*} Returns the last element of `array`.
      * @example
      *
-     * var object = { 'name': 'fred' };
-     * var copy = { 'name': 'fred' };
+     * _.last([1, 2, 3]);
+     * // => 3
+     */
+    function last(array) {
+      var length = array == null ? 0 : array.length;
+      return length ? array[length - 1] : undefined;
+    }
+
+    /**
+     * This method is like `_.indexOf` except that it iterates over elements of
+     * `array` from right to left.
+     *
+     * @static
+     * @memberOf _
+     * @since 0.1.0
+     * @category Array
+     * @param {Array} array The array to inspect.
+     * @param {*} value The value to search for.
+     * @param {number} [fromIndex=array.length-1] The index to search from.
+     * @returns {number} Returns the index of the matched value, else `-1`.
+     * @example
      *
-     * object == copy;
-     * // => false
+     * _.lastIndexOf([1, 2, 1, 2], 2);
+     * // => 3
      *
-     * _.isEqual(object, copy);
-     * // => true
+     * // Search from the `fromIndex`.
+     * _.lastIndexOf([1, 2, 1, 2], 2, 2);
+     * // => 1
+     */
+    function lastIndexOf(array, value, fromIndex) {
+      var length = array == null ? 0 : array.length;
+      if (!length) {
+        return -1;
+      }
+      var index = length;
+      if (fromIndex !== undefined) {
+        index = toInteger(fromIndex);
+        index = index < 0 ? nativeMax(length + index, 0) : nativeMin(index, length - 1);
+      }
+      return value === value
+        ? strictLastIndexOf(array, value, index)
+        : baseFindIndex(array, baseIsNaN, index, true);
+    }
+
+    /**
+     * Gets the element at index `n` of `array`. If `n` is negative, the nth
+     * element from the end is returned.
      *
-     * var words = ['hello', 'goodbye'];
-     * var otherWords = ['hi', 'goodbye'];
+     * @static
+     * @memberOf _
+     * @since 4.11.0
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {number} [n=0] The index of the element to return.
+     * @returns {*} Returns the nth element of `array`.
+     * @example
      *
-     * _.isEqual(words, otherWords, function(a, b) {
-     *   var reGreet = /^(?:hello|hi)$/i,
-     *       aGreet = _.isString(a) && reGreet.test(a),
-     *       bGreet = _.isString(b) && reGreet.test(b);
+     * var array = ['a', 'b', 'c', 'd'];
      *
-     *   return (aGreet || bGreet) ? (aGreet == bGreet) : undefined;
-     * });
-     * // => true
+     * _.nth(array, 1);
+     * // => 'b'
+     *
+     * _.nth(array, -2);
+     * // => 'c';
      */
-    function isEqual(a, b, callback, thisArg) {
-      return baseIsEqual(a, b, typeof callback == 'function' && baseCreateCallback(callback, thisArg, 2));
+    function nth(array, n) {
+      return (array && array.length) ? baseNth(array, toInteger(n)) : undefined;
     }
 
     /**
-     * Checks if `value` is, or can be coerced to, a finite number.
+     * Removes all given values from `array` using
+     * [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
+     * for equality comparisons.
      *
-     * Note: This is not the same as native `isFinite` which will return true for
-     * booleans and empty strings. See http://es5.github.io/#x15.1.2.5.
+     * **Note:** Unlike `_.without`, this method mutates `array`. Use `_.remove`
+     * to remove elements from an array by predicate.
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is finite, else `false`.
+     * @since 2.0.0
+     * @category Array
+     * @param {Array} array The array to modify.
+     * @param {...*} [values] The values to remove.
+     * @returns {Array} Returns `array`.
      * @example
      *
-     * _.isFinite(-101);
-     * // => true
+     * var array = ['a', 'b', 'c', 'a', 'b', 'c'];
      *
-     * _.isFinite('10');
-     * // => true
+     * _.pull(array, 'a', 'c');
+     * console.log(array);
+     * // => ['b', 'b']
+     */
+    var pull = baseRest(pullAll);
+
+    /**
+     * This method is like `_.pull` except that it accepts an array of values to remove.
      *
-     * _.isFinite(true);
-     * // => false
+     * **Note:** Unlike `_.difference`, this method mutates `array`.
      *
-     * _.isFinite('');
-     * // => false
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Array
+     * @param {Array} array The array to modify.
+     * @param {Array} values The values to remove.
+     * @returns {Array} Returns `array`.
+     * @example
      *
-     * _.isFinite(Infinity);
-     * // => false
+     * var array = ['a', 'b', 'c', 'a', 'b', 'c'];
+     *
+     * _.pullAll(array, ['a', 'c']);
+     * console.log(array);
+     * // => ['b', 'b']
      */
-    function isFinite(value) {
-      return nativeIsFinite(value) && !nativeIsNaN(parseFloat(value));
+    function pullAll(array, values) {
+      return (array && array.length && values && values.length)
+        ? basePullAll(array, values)
+        : array;
     }
 
     /**
-     * Checks if `value` is a function.
+     * This method is like `_.pullAll` except that it accepts `iteratee` which is
+     * invoked for each element of `array` and `values` to generate the criterion
+     * by which they're compared. The iteratee is invoked with one argument: (value).
+     *
+     * **Note:** Unlike `_.differenceBy`, this method mutates `array`.
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a function, else `false`.
+     * @since 4.0.0
+     * @category Array
+     * @param {Array} array The array to modify.
+     * @param {Array} values The values to remove.
+     * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+     * @returns {Array} Returns `array`.
      * @example
      *
-     * _.isFunction(_);
-     * // => true
+     * var array = [{ 'x': 1 }, { 'x': 2 }, { 'x': 3 }, { 'x': 1 }];
+     *
+     * _.pullAllBy(array, [{ 'x': 1 }, { 'x': 3 }], 'x');
+     * console.log(array);
+     * // => [{ 'x': 2 }]
      */
-    function isFunction(value) {
-      return typeof value == 'function';
+    function pullAllBy(array, values, iteratee) {
+      return (array && array.length && values && values.length)
+        ? basePullAll(array, values, getIteratee(iteratee, 2))
+        : array;
     }
-    // fallback for older versions of Chrome and Safari
-    if (isFunction(/x/)) {
-      isFunction = function(value) {
-        return typeof value == 'function' && toString.call(value) == funcClass;
-      };
+
+    /**
+     * This method is like `_.pullAll` except that it accepts `comparator` which
+     * is invoked to compare elements of `array` to `values`. The comparator is
+     * invoked with two arguments: (arrVal, othVal).
+     *
+     * **Note:** Unlike `_.differenceWith`, this method mutates `array`.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.6.0
+     * @category Array
+     * @param {Array} array The array to modify.
+     * @param {Array} values The values to remove.
+     * @param {Function} [comparator] The comparator invoked per element.
+     * @returns {Array} Returns `array`.
+     * @example
+     *
+     * var array = [{ 'x': 1, 'y': 2 }, { 'x': 3, 'y': 4 }, { 'x': 5, 'y': 6 }];
+     *
+     * _.pullAllWith(array, [{ 'x': 3, 'y': 4 }], _.isEqual);
+     * console.log(array);
+     * // => [{ 'x': 1, 'y': 2 }, { 'x': 5, 'y': 6 }]
+     */
+    function pullAllWith(array, values, comparator) {
+      return (array && array.length && values && values.length)
+        ? basePullAll(array, values, undefined, comparator)
+        : array;
     }
 
     /**
-     * Checks if `value` is the language type of Object.
-     * (e.g. arrays, functions, objects, regexes, `new Number(0)`, and `new String('')`)
+     * Removes elements from `array` corresponding to `indexes` and returns an
+     * array of removed elements.
+     *
+     * **Note:** Unlike `_.at`, this method mutates `array`.
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is an object, else `false`.
+     * @since 3.0.0
+     * @category Array
+     * @param {Array} array The array to modify.
+     * @param {...(number|number[])} [indexes] The indexes of elements to remove.
+     * @returns {Array} Returns the new array of removed elements.
      * @example
      *
-     * _.isObject({});
-     * // => true
+     * var array = ['a', 'b', 'c', 'd'];
+     * var pulled = _.pullAt(array, [1, 3]);
      *
-     * _.isObject([1, 2, 3]);
-     * // => true
+     * console.log(array);
+     * // => ['a', 'c']
      *
-     * _.isObject(1);
-     * // => false
+     * console.log(pulled);
+     * // => ['b', 'd']
      */
-    function isObject(value) {
-      // check if the value is the ECMAScript language type of Object
-      // http://es5.github.io/#x8
-      // and avoid a V8 bug
-      // http://code.google.com/p/v8/issues/detail?id=2291
-      return !!(value && objectTypes[typeof value]);
+    var pullAt = flatRest(function(array, indexes) {
+      var length = array == null ? 0 : array.length,
+          result = baseAt(array, indexes);
+
+      basePullAt(array, arrayMap(indexes, function(index) {
+        return isIndex(index, length) ? +index : index;
+      }).sort(compareAscending));
+
+      return result;
+    });
+
+    /**
+     * Removes all elements from `array` that `predicate` returns truthy for
+     * and returns an array of the removed elements. The predicate is invoked
+     * with three arguments: (value, index, array).
+     *
+     * **Note:** Unlike `_.filter`, this method mutates `array`. Use `_.pull`
+     * to pull elements from an array by value.
+     *
+     * @static
+     * @memberOf _
+     * @since 2.0.0
+     * @category Array
+     * @param {Array} array The array to modify.
+     * @param {Function} [predicate=_.identity] The function invoked per iteration.
+     * @returns {Array} Returns the new array of removed elements.
+     * @example
+     *
+     * var array = [1, 2, 3, 4];
+     * var evens = _.remove(array, function(n) {
+     *   return n % 2 == 0;
+     * });
+     *
+     * console.log(array);
+     * // => [1, 3]
+     *
+     * console.log(evens);
+     * // => [2, 4]
+     */
+    function remove(array, predicate) {
+      var result = [];
+      if (!(array && array.length)) {
+        return result;
+      }
+      var index = -1,
+          indexes = [],
+          length = array.length;
+
+      predicate = getIteratee(predicate, 3);
+      while (++index < length) {
+        var value = array[index];
+        if (predicate(value, index, array)) {
+          result.push(value);
+          indexes.push(index);
+        }
+      }
+      basePullAt(array, indexes);
+      return result;
     }
 
     /**
-     * Checks if `value` is `NaN`.
+     * Reverses `array` so that the first element becomes the last, the second
+     * element becomes the second to last, and so on.
      *
-     * Note: This is not the same as native `isNaN` which will return `true` for
-     * `undefined` and other non-numeric values. See http://es5.github.io/#x15.1.2.4.
+     * **Note:** This method mutates `array` and is based on
+     * [`Array#reverse`](https://mdn.io/Array/reverse).
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is `NaN`, else `false`.
+     * @since 4.0.0
+     * @category Array
+     * @param {Array} array The array to modify.
+     * @returns {Array} Returns `array`.
      * @example
      *
-     * _.isNaN(NaN);
-     * // => true
+     * var array = [1, 2, 3];
      *
-     * _.isNaN(new Number(NaN));
-     * // => true
+     * _.reverse(array);
+     * // => [3, 2, 1]
      *
-     * isNaN(undefined);
-     * // => true
+     * console.log(array);
+     * // => [3, 2, 1]
+     */
+    function reverse(array) {
+      return array == null ? array : nativeReverse.call(array);
+    }
+
+    /**
+     * Creates a slice of `array` from `start` up to, but not including, `end`.
      *
-     * _.isNaN(undefined);
-     * // => false
+     * **Note:** This method is used instead of
+     * [`Array#slice`](https://mdn.io/Array/slice) to ensure dense arrays are
+     * returned.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category Array
+     * @param {Array} array The array to slice.
+     * @param {number} [start=0] The start position.
+     * @param {number} [end=array.length] The end position.
+     * @returns {Array} Returns the slice of `array`.
      */
-    function isNaN(value) {
-      // `NaN` as a primitive is the only value that is not equal to itself
-      // (perform the [[Class]] check first to avoid errors with some host objects in IE)
-      return isNumber(value) && value != +value;
+    function slice(array, start, end) {
+      var length = array == null ? 0 : array.length;
+      if (!length) {
+        return [];
+      }
+      if (end && typeof end != 'number' && isIterateeCall(array, start, end)) {
+        start = 0;
+        end = length;
+      }
+      else {
+        start = start == null ? 0 : toInteger(start);
+        end = end === undefined ? length : toInteger(end);
+      }
+      return baseSlice(array, start, end);
     }
 
     /**
-     * Checks if `value` is `null`.
+     * Uses a binary search to determine the lowest index at which `value`
+     * should be inserted into `array` in order to maintain its sort order.
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is `null`, else `false`.
+     * @since 0.1.0
+     * @category Array
+     * @param {Array} array The sorted array to inspect.
+     * @param {*} value The value to evaluate.
+     * @returns {number} Returns the index at which `value` should be inserted
+     *  into `array`.
      * @example
      *
-     * _.isNull(null);
-     * // => true
+     * _.sortedIndex([30, 50], 40);
+     * // => 1
+     */
+    function sortedIndex(array, value) {
+      return baseSortedIndex(array, value);
+    }
+
+    /**
+     * This method is like `_.sortedIndex` except that it accepts `iteratee`
+     * which is invoked for `value` and each element of `array` to compute their
+     * sort ranking. The iteratee is invoked with one argument: (value).
      *
-     * _.isNull(undefined);
-     * // => false
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Array
+     * @param {Array} array The sorted array to inspect.
+     * @param {*} value The value to evaluate.
+     * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+     * @returns {number} Returns the index at which `value` should be inserted
+     *  into `array`.
+     * @example
+     *
+     * var objects = [{ 'x': 4 }, { 'x': 5 }];
+     *
+     * _.sortedIndexBy(objects, { 'x': 4 }, function(o) { return o.x; });
+     * // => 0
+     *
+     * // The `_.property` iteratee shorthand.
+     * _.sortedIndexBy(objects, { 'x': 4 }, 'x');
+     * // => 0
      */
-    function isNull(value) {
-      return value === null;
+    function sortedIndexBy(array, value, iteratee) {
+      return baseSortedIndexBy(array, value, getIteratee(iteratee, 2));
     }
 
     /**
-     * Checks if `value` is a number.
+     * This method is like `_.indexOf` except that it performs a binary
+     * search on a sorted `array`.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Array
+     * @param {Array} array The array to inspect.
+     * @param {*} value The value to search for.
+     * @returns {number} Returns the index of the matched value, else `-1`.
+     * @example
      *
-     * Note: `NaN` is considered a number. See http://es5.github.io/#x8.5.
+     * _.sortedIndexOf([4, 5, 5, 5, 6], 5);
+     * // => 1
+     */
+    function sortedIndexOf(array, value) {
+      var length = array == null ? 0 : array.length;
+      if (length) {
+        var index = baseSortedIndex(array, value);
+        if (index < length && eq(array[index], value)) {
+          return index;
+        }
+      }
+      return -1;
+    }
+
+    /**
+     * This method is like `_.sortedIndex` except that it returns the highest
+     * index at which `value` should be inserted into `array` in order to
+     * maintain its sort order.
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a number, else `false`.
+     * @since 3.0.0
+     * @category Array
+     * @param {Array} array The sorted array to inspect.
+     * @param {*} value The value to evaluate.
+     * @returns {number} Returns the index at which `value` should be inserted
+     *  into `array`.
      * @example
      *
-     * _.isNumber(8.4 * 5);
-     * // => true
+     * _.sortedLastIndex([4, 5, 5, 5, 6], 5);
+     * // => 4
      */
-    function isNumber(value) {
-      return typeof value == 'number' ||
-        value && typeof value == 'object' && toString.call(value) == numberClass || false;
+    function sortedLastIndex(array, value) {
+      return baseSortedIndex(array, value, true);
     }
 
     /**
-     * Checks if `value` is an object created by the `Object` constructor.
+     * This method is like `_.sortedLastIndex` except that it accepts `iteratee`
+     * which is invoked for `value` and each element of `array` to compute their
+     * sort ranking. The iteratee is invoked with one argument: (value).
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if `value` is a plain object, else `false`.
+     * @since 4.0.0
+     * @category Array
+     * @param {Array} array The sorted array to inspect.
+     * @param {*} value The value to evaluate.
+     * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+     * @returns {number} Returns the index at which `value` should be inserted
+     *  into `array`.
      * @example
      *
-     * function Shape() {
-     *   this.x = 0;
-     *   this.y = 0;
-     * }
+     * var objects = [{ 'x': 4 }, { 'x': 5 }];
      *
-     * _.isPlainObject(new Shape);
-     * // => false
+     * _.sortedLastIndexBy(objects, { 'x': 4 }, function(o) { return o.x; });
+     * // => 1
      *
-     * _.isPlainObject([1, 2, 3]);
-     * // => false
+     * // The `_.property` iteratee shorthand.
+     * _.sortedLastIndexBy(objects, { 'x': 4 }, 'x');
+     * // => 1
+     */
+    function sortedLastIndexBy(array, value, iteratee) {
+      return baseSortedIndexBy(array, value, getIteratee(iteratee, 2), true);
+    }
+
+    /**
+     * This method is like `_.lastIndexOf` except that it performs a binary
+     * search on a sorted `array`.
      *
-     * _.isPlainObject({ 'x': 0, 'y': 0 });
-     * // => true
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Array
+     * @param {Array} array The array to inspect.
+     * @param {*} value The value to search for.
+     * @returns {number} Returns the index of the matched value, else `-1`.
+     * @example
+     *
+     * _.sortedLastIndexOf([4, 5, 5, 5, 6], 5);
+     * // => 3
      */
-    var isPlainObject = !getPrototypeOf ? shimIsPlainObject : function(value) {
-      if (!(value && toString.call(value) == objectClass) || (!support.argsClass && isArguments(value))) {
-        return false;
+    function sortedLastIndexOf(array, value) {
+      var length = array == null ? 0 : array.length;
+      if (length) {
+        var index = baseSortedIndex(array, value, true) - 1;
+        if (eq(array[index], value)) {
+          return index;
+        }
       }
-      var valueOf = value.valueOf,
-          objProto = isNative(valueOf) && (objProto = getPrototypeOf(valueOf)) && getPrototypeOf(objProto);
-
-      return objProto
-        ? (value == objProto || getPrototypeOf(value) == objProto)
-        : shimIsPlainObject(value);
-    };
+      return -1;
+    }
 
     /**
-     * Checks if `value` is a regular expression.
+     * This method is like `_.uniq` except that it's designed and optimized
+     * for sorted arrays.
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a regular expression, else `false`.
+     * @since 4.0.0
+     * @category Array
+     * @param {Array} array The array to inspect.
+     * @returns {Array} Returns the new duplicate free array.
      * @example
      *
-     * _.isRegExp(/fred/);
-     * // => true
+     * _.sortedUniq([1, 1, 2]);
+     * // => [1, 2]
      */
-    function isRegExp(value) {
-      return value && objectTypes[typeof value] && toString.call(value) == regexpClass || false;
+    function sortedUniq(array) {
+      return (array && array.length)
+        ? baseSortedUniq(array)
+        : [];
     }
 
     /**
-     * Checks if `value` is a string.
+     * This method is like `_.uniqBy` except that it's designed and optimized
+     * for sorted arrays.
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a string, else `false`.
+     * @since 4.0.0
+     * @category Array
+     * @param {Array} array The array to inspect.
+     * @param {Function} [iteratee] The iteratee invoked per element.
+     * @returns {Array} Returns the new duplicate free array.
      * @example
      *
-     * _.isString('fred');
-     * // => true
+     * _.sortedUniqBy([1.1, 1.2, 2.3, 2.4], Math.floor);
+     * // => [1.1, 2.3]
      */
-    function isString(value) {
-      return typeof value == 'string' ||
-        value && typeof value == 'object' && toString.call(value) == stringClass || false;
+    function sortedUniqBy(array, iteratee) {
+      return (array && array.length)
+        ? baseSortedUniq(array, getIteratee(iteratee, 2))
+        : [];
     }
 
     /**
-     * Checks if `value` is `undefined`.
+     * Gets all but the first element of `array`.
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is `undefined`, else `false`.
+     * @since 4.0.0
+     * @category Array
+     * @param {Array} array The array to query.
+     * @returns {Array} Returns the slice of `array`.
      * @example
      *
-     * _.isUndefined(void 0);
-     * // => true
+     * _.tail([1, 2, 3]);
+     * // => [2, 3]
      */
-    function isUndefined(value) {
-      return typeof value == 'undefined';
+    function tail(array) {
+      var length = array == null ? 0 : array.length;
+      return length ? baseSlice(array, 1, length) : [];
     }
 
     /**
-     * Creates an object with the same keys as `object` and values generated by
-     * running each own enumerable property of `object` through the callback.
-     * The callback is bound to `thisArg` and invoked with three arguments;
-     * (value, key, object).
+     * Creates a slice of `array` with `n` elements taken from the beginning.
+     *
+     * @static
+     * @memberOf _
+     * @since 0.1.0
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {number} [n=1] The number of elements to take.
+     * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
+     * @returns {Array} Returns the slice of `array`.
+     * @example
+     *
+     * _.take([1, 2, 3]);
+     * // => [1]
+     *
+     * _.take([1, 2, 3], 2);
+     * // => [1, 2]
      *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
+     * _.take([1, 2, 3], 5);
+     * // => [1, 2, 3]
      *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * _.take([1, 2, 3], 0);
+     * // => []
+     */
+    function take(array, n, guard) {
+      if (!(array && array.length)) {
+        return [];
+      }
+      n = (guard || n === undefined) ? 1 : toInteger(n);
+      return baseSlice(array, 0, n < 0 ? 0 : n);
+    }
+
+    /**
+     * Creates a slice of `array` with `n` elements taken from the end.
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a new object with values of the results of each `callback` execution.
+     * @since 3.0.0
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {number} [n=1] The number of elements to take.
+     * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
+     * @returns {Array} Returns the slice of `array`.
      * @example
      *
-     * _.mapValues({ 'a': 1, 'b': 2, 'c': 3} , function(num) { return num * 3; });
-     * // => { 'a': 3, 'b': 6, 'c': 9 }
-     *
-     * var characters = {
-     *   'fred': { 'name': 'fred', 'age': 40 },
-     *   'pebbles': { 'name': 'pebbles', 'age': 1 }
-     * };
+     * _.takeRight([1, 2, 3]);
+     * // => [3]
      *
-     * // using "_.pluck" callback shorthand
-     * _.mapValues(characters, 'age');
-     * // => { 'fred': 40, 'pebbles': 1 }
+     * _.takeRight([1, 2, 3], 2);
+     * // => [2, 3]
+     *
+     * _.takeRight([1, 2, 3], 5);
+     * // => [1, 2, 3]
+     *
+     * _.takeRight([1, 2, 3], 0);
+     * // => []
      */
-    function mapValues(object, callback, thisArg) {
-      var result = {};
-      callback = lodash.createCallback(callback, thisArg, 3);
+    function takeRight(array, n, guard) {
+      var length = array == null ? 0 : array.length;
+      if (!length) {
+        return [];
+      }
+      n = (guard || n === undefined) ? 1 : toInteger(n);
+      n = length - n;
+      return baseSlice(array, n < 0 ? 0 : n, length);
+    }
 
-      forOwn(object, function(value, key, object) {
-        result[key] = callback(value, key, object);
-      });
-      return result;
+    /**
+     * Creates a slice of `array` with elements taken from the end. Elements are
+     * taken until `predicate` returns falsey. The predicate is invoked with
+     * three arguments: (value, index, array).
+     *
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {Function} [predicate=_.identity] The function invoked per iteration.
+     * @returns {Array} Returns the slice of `array`.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney',  'active': true },
+     *   { 'user': 'fred',    'active': false },
+     *   { 'user': 'pebbles', 'active': false }
+     * ];
+     *
+     * _.takeRightWhile(users, function(o) { return !o.active; });
+     * // => objects for ['fred', 'pebbles']
+     *
+     * // The `_.matches` iteratee shorthand.
+     * _.takeRightWhile(users, { 'user': 'pebbles', 'active': false });
+     * // => objects for ['pebbles']
+     *
+     * // The `_.matchesProperty` iteratee shorthand.
+     * _.takeRightWhile(users, ['active', false]);
+     * // => objects for ['fred', 'pebbles']
+     *
+     * // The `_.property` iteratee shorthand.
+     * _.takeRightWhile(users, 'active');
+     * // => []
+     */
+    function takeRightWhile(array, predicate) {
+      return (array && array.length)
+        ? baseWhile(array, getIteratee(predicate, 3), false, true)
+        : [];
     }
 
     /**
-     * Recursively merges own enumerable properties of the source object(s), that
-     * don't resolve to `undefined` into the destination object. Subsequent sources
-     * will overwrite property assignments of previous sources. If a callback is
-     * provided it will be executed to produce the merged values of the destination
-     * and source properties. If the callback returns `undefined` merging will
-     * be handled by the method instead. The callback is bound to `thisArg` and
-     * invoked with two arguments; (objectValue, sourceValue).
+     * Creates a slice of `array` with elements taken from the beginning. Elements
+     * are taken until `predicate` returns falsey. The predicate is invoked with
+     * three arguments: (value, index, array).
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {Object} object The destination object.
-     * @param {...Object} [source] The source objects.
-     * @param {Function} [callback] The function to customize merging properties.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns the destination object.
+     * @since 3.0.0
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {Function} [predicate=_.identity] The function invoked per iteration.
+     * @returns {Array} Returns the slice of `array`.
      * @example
      *
-     * var names = {
-     *   'characters': [
-     *     { 'name': 'barney' },
-     *     { 'name': 'fred' }
-     *   ]
-     * };
+     * var users = [
+     *   { 'user': 'barney',  'active': false },
+     *   { 'user': 'fred',    'active': false },
+     *   { 'user': 'pebbles', 'active': true }
+     * ];
      *
-     * var ages = {
-     *   'characters': [
-     *     { 'age': 36 },
-     *     { 'age': 40 }
-     *   ]
-     * };
+     * _.takeWhile(users, function(o) { return !o.active; });
+     * // => objects for ['barney', 'fred']
      *
-     * _.merge(names, ages);
-     * // => { 'characters': [{ 'name': 'barney', 'age': 36 }, { 'name': 'fred', 'age': 40 }] }
+     * // The `_.matches` iteratee shorthand.
+     * _.takeWhile(users, { 'user': 'barney', 'active': false });
+     * // => objects for ['barney']
+     *
+     * // The `_.matchesProperty` iteratee shorthand.
+     * _.takeWhile(users, ['active', false]);
+     * // => objects for ['barney', 'fred']
      *
-     * var food = {
-     *   'fruits': ['apple'],
-     *   'vegetables': ['beet']
-     * };
+     * // The `_.property` iteratee shorthand.
+     * _.takeWhile(users, 'active');
+     * // => []
+     */
+    function takeWhile(array, predicate) {
+      return (array && array.length)
+        ? baseWhile(array, getIteratee(predicate, 3))
+        : [];
+    }
+
+    /**
+     * Creates an array of unique values, in order, from all given arrays using
+     * [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
+     * for equality comparisons.
      *
-     * var otherFood = {
-     *   'fruits': ['banana'],
-     *   'vegetables': ['carrot']
-     * };
+     * @static
+     * @memberOf _
+     * @since 0.1.0
+     * @category Array
+     * @param {...Array} [arrays] The arrays to inspect.
+     * @returns {Array} Returns the new array of combined values.
+     * @example
      *
-     * _.merge(food, otherFood, function(a, b) {
-     *   return _.isArray(a) ? a.concat(b) : undefined;
-     * });
-     * // => { 'fruits': ['apple', 'banana'], 'vegetables': ['beet', 'carrot] }
+     * _.union([2], [1, 2]);
+     * // => [2, 1]
      */
-    function merge(object) {
-      var args = arguments,
-          length = 2;
+    var union = baseRest(function(arrays) {
+      return baseUniq(baseFlatten(arrays, 1, isArrayLikeObject, true));
+    });
 
-      if (!isObject(object)) {
-        return object;
-      }
-      // allows working with `_.reduce` and `_.reduceRight` without using
-      // their `index` and `collection` arguments
-      if (typeof args[2] != 'number') {
-        length = args.length;
-      }
-      if (length > 3 && typeof args[length - 2] == 'function') {
-        var callback = baseCreateCallback(args[--length - 1], args[length--], 2);
-      } else if (length > 2 && typeof args[length - 1] == 'function') {
-        callback = args[--length];
+    /**
+     * This method is like `_.union` except that it accepts `iteratee` which is
+     * invoked for each element of each `arrays` to generate the criterion by
+     * which uniqueness is computed. Result values are chosen from the first
+     * array in which the value occurs. The iteratee is invoked with one argument:
+     * (value).
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Array
+     * @param {...Array} [arrays] The arrays to inspect.
+     * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+     * @returns {Array} Returns the new array of combined values.
+     * @example
+     *
+     * _.unionBy([2.1], [1.2, 2.3], Math.floor);
+     * // => [2.1, 1.2]
+     *
+     * // The `_.property` iteratee shorthand.
+     * _.unionBy([{ 'x': 1 }], [{ 'x': 2 }, { 'x': 1 }], 'x');
+     * // => [{ 'x': 1 }, { 'x': 2 }]
+     */
+    var unionBy = baseRest(function(arrays) {
+      var iteratee = last(arrays);
+      if (isArrayLikeObject(iteratee)) {
+        iteratee = undefined;
       }
-      var sources = slice(arguments, 1, length),
-          index = -1,
-          stackA = getArray(),
-          stackB = getArray();
+      return baseUniq(baseFlatten(arrays, 1, isArrayLikeObject, true), getIteratee(iteratee, 2));
+    });
 
-      while (++index < length) {
-        baseMerge(object, sources[index], callback, stackA, stackB);
-      }
-      releaseArray(stackA);
-      releaseArray(stackB);
-      return object;
+    /**
+     * This method is like `_.union` except that it accepts `comparator` which
+     * is invoked to compare elements of `arrays`. Result values are chosen from
+     * the first array in which the value occurs. The comparator is invoked
+     * with two arguments: (arrVal, othVal).
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Array
+     * @param {...Array} [arrays] The arrays to inspect.
+     * @param {Function} [comparator] The comparator invoked per element.
+     * @returns {Array} Returns the new array of combined values.
+     * @example
+     *
+     * var objects = [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }];
+     * var others = [{ 'x': 1, 'y': 1 }, { 'x': 1, 'y': 2 }];
+     *
+     * _.unionWith(objects, others, _.isEqual);
+     * // => [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }, { 'x': 1, 'y': 1 }]
+     */
+    var unionWith = baseRest(function(arrays) {
+      var comparator = last(arrays);
+      comparator = typeof comparator == 'function' ? comparator : undefined;
+      return baseUniq(baseFlatten(arrays, 1, isArrayLikeObject, true), undefined, comparator);
+    });
+
+    /**
+     * Creates a duplicate-free version of an array, using
+     * [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
+     * for equality comparisons, in which only the first occurrence of each element
+     * is kept. The order of result values is determined by the order they occur
+     * in the array.
+     *
+     * @static
+     * @memberOf _
+     * @since 0.1.0
+     * @category Array
+     * @param {Array} array The array to inspect.
+     * @returns {Array} Returns the new duplicate free array.
+     * @example
+     *
+     * _.uniq([2, 1, 2]);
+     * // => [2, 1]
+     */
+    function uniq(array) {
+      return (array && array.length) ? baseUniq(array) : [];
     }
 
     /**
-     * Creates a shallow clone of `object` excluding the specified properties.
-     * Property names may be specified as individual arguments or as arrays of
-     * property names. If a callback is provided it will be executed for each
-     * property of `object` omitting the properties the callback returns truey
-     * for. The callback is bound to `thisArg` and invoked with three arguments;
-     * (value, key, object).
+     * This method is like `_.uniq` except that it accepts `iteratee` which is
+     * invoked for each element in `array` to generate the criterion by which
+     * uniqueness is computed. The order of result values is determined by the
+     * order they occur in the array. The iteratee is invoked with one argument:
+     * (value).
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {Object} object The source object.
-     * @param {Function|...string|string[]} [callback] The properties to omit or the
-     *  function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns an object without the omitted properties.
+     * @since 4.0.0
+     * @category Array
+     * @param {Array} array The array to inspect.
+     * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+     * @returns {Array} Returns the new duplicate free array.
      * @example
      *
-     * _.omit({ 'name': 'fred', 'age': 40 }, 'age');
-     * // => { 'name': 'fred' }
+     * _.uniqBy([2.1, 1.2, 2.3], Math.floor);
+     * // => [2.1, 1.2]
      *
-     * _.omit({ 'name': 'fred', 'age': 40 }, function(value) {
-     *   return typeof value == 'number';
-     * });
-     * // => { 'name': 'fred' }
+     * // The `_.property` iteratee shorthand.
+     * _.uniqBy([{ 'x': 1 }, { 'x': 2 }, { 'x': 1 }], 'x');
+     * // => [{ 'x': 1 }, { 'x': 2 }]
      */
-    function omit(object, callback, thisArg) {
-      var result = {};
-      if (typeof callback != 'function') {
-        var props = [];
-        forIn(object, function(value, key) {
-          props.push(key);
-        });
-        props = baseDifference(props, baseFlatten(arguments, true, false, 1));
+    function uniqBy(array, iteratee) {
+      return (array && array.length) ? baseUniq(array, getIteratee(iteratee, 2)) : [];
+    }
 
-        var index = -1,
-            length = props.length;
+    /**
+     * This method is like `_.uniq` except that it accepts `comparator` which
+     * is invoked to compare elements of `array`. The order of result values is
+     * determined by the order they occur in the array.The comparator is invoked
+     * with two arguments: (arrVal, othVal).
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Array
+     * @param {Array} array The array to inspect.
+     * @param {Function} [comparator] The comparator invoked per element.
+     * @returns {Array} Returns the new duplicate free array.
+     * @example
+     *
+     * var objects = [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }, { 'x': 1, 'y': 2 }];
+     *
+     * _.uniqWith(objects, _.isEqual);
+     * // => [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }]
+     */
+    function uniqWith(array, comparator) {
+      comparator = typeof comparator == 'function' ? comparator : undefined;
+      return (array && array.length) ? baseUniq(array, undefined, comparator) : [];
+    }
 
-        while (++index < length) {
-          var key = props[index];
-          result[key] = object[key];
-        }
-      } else {
-        callback = lodash.createCallback(callback, thisArg, 3);
-        forIn(object, function(value, key, object) {
-          if (!callback(value, key, object)) {
-            result[key] = value;
-          }
-        });
+    /**
+     * This method is like `_.zip` except that it accepts an array of grouped
+     * elements and creates an array regrouping the elements to their pre-zip
+     * configuration.
+     *
+     * @static
+     * @memberOf _
+     * @since 1.2.0
+     * @category Array
+     * @param {Array} array The array of grouped elements to process.
+     * @returns {Array} Returns the new array of regrouped elements.
+     * @example
+     *
+     * var zipped = _.zip(['a', 'b'], [1, 2], [true, false]);
+     * // => [['a', 1, true], ['b', 2, false]]
+     *
+     * _.unzip(zipped);
+     * // => [['a', 'b'], [1, 2], [true, false]]
+     */
+    function unzip(array) {
+      if (!(array && array.length)) {
+        return [];
       }
-      return result;
+      var length = 0;
+      array = arrayFilter(array, function(group) {
+        if (isArrayLikeObject(group)) {
+          length = nativeMax(group.length, length);
+          return true;
+        }
+      });
+      return baseTimes(length, function(index) {
+        return arrayMap(array, baseProperty(index));
+      });
     }
 
     /**
-     * Creates a two dimensional array of an object's key-value pairs,
-     * i.e. `[[key1, value1], [key2, value2]]`.
+     * This method is like `_.unzip` except that it accepts `iteratee` to specify
+     * how regrouped values should be combined. The iteratee is invoked with the
+     * elements of each group: (...group).
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to inspect.
-     * @returns {Array} Returns new array of key-value pairs.
+     * @since 3.8.0
+     * @category Array
+     * @param {Array} array The array of grouped elements to process.
+     * @param {Function} [iteratee=_.identity] The function to combine
+     *  regrouped values.
+     * @returns {Array} Returns the new array of regrouped elements.
      * @example
      *
-     * _.pairs({ 'barney': 36, 'fred': 40 });
-     * // => [['barney', 36], ['fred', 40]] (property order is not guaranteed across environments)
+     * var zipped = _.zip([1, 2], [10, 20], [100, 200]);
+     * // => [[1, 10, 100], [2, 20, 200]]
+     *
+     * _.unzipWith(zipped, _.add);
+     * // => [3, 30, 300]
      */
-    function pairs(object) {
-      var index = -1,
-          props = keys(object),
-          length = props.length,
-          result = Array(length);
-
-      while (++index < length) {
-        var key = props[index];
-        result[index] = [key, object[key]];
+    function unzipWith(array, iteratee) {
+      if (!(array && array.length)) {
+        return [];
       }
-      return result;
+      var result = unzip(array);
+      if (iteratee == null) {
+        return result;
+      }
+      return arrayMap(result, function(group) {
+        return apply(iteratee, undefined, group);
+      });
     }
 
     /**
-     * Creates a shallow clone of `object` composed of the specified properties.
-     * Property names may be specified as individual arguments or as arrays of
-     * property names. If a callback is provided it will be executed for each
-     * property of `object` picking the properties the callback returns truey
-     * for. The callback is bound to `thisArg` and invoked with three arguments;
-     * (value, key, object).
+     * Creates an array excluding all given values using
+     * [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
+     * for equality comparisons.
+     *
+     * **Note:** Unlike `_.pull`, this method returns a new array.
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {Object} object The source object.
-     * @param {Function|...string|string[]} [callback] The function called per
-     *  iteration or property names to pick, specified as individual property
-     *  names or arrays of property names.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns an object composed of the picked properties.
+     * @since 0.1.0
+     * @category Array
+     * @param {Array} array The array to inspect.
+     * @param {...*} [values] The values to exclude.
+     * @returns {Array} Returns the new array of filtered values.
+     * @see _.difference, _.xor
      * @example
      *
-     * _.pick({ 'name': 'fred', '_userid': 'fred1' }, 'name');
-     * // => { 'name': 'fred' }
+     * _.without([2, 1, 2, 3], 1, 2);
+     * // => [3]
+     */
+    var without = baseRest(function(array, values) {
+      return isArrayLikeObject(array)
+        ? baseDifference(array, values)
+        : [];
+    });
+
+    /**
+     * Creates an array of unique values that is the
+     * [symmetric difference](https://en.wikipedia.org/wiki/Symmetric_difference)
+     * of the given arrays. The order of result values is determined by the order
+     * they occur in the arrays.
      *
-     * _.pick({ 'name': 'fred', '_userid': 'fred1' }, function(value, key) {
-     *   return key.charAt(0) != '_';
-     * });
-     * // => { 'name': 'fred' }
+     * @static
+     * @memberOf _
+     * @since 2.4.0
+     * @category Array
+     * @param {...Array} [arrays] The arrays to inspect.
+     * @returns {Array} Returns the new array of filtered values.
+     * @see _.difference, _.without
+     * @example
+     *
+     * _.xor([2, 1], [2, 3]);
+     * // => [1, 3]
      */
-    function pick(object, callback, thisArg) {
-      var result = {};
-      if (typeof callback != 'function') {
-        var index = -1,
-            props = baseFlatten(arguments, true, false, 1),
-            length = isObject(object) ? props.length : 0;
+    var xor = baseRest(function(arrays) {
+      return baseXor(arrayFilter(arrays, isArrayLikeObject));
+    });
 
-        while (++index < length) {
-          var key = props[index];
-          if (key in object) {
-            result[key] = object[key];
-          }
-        }
-      } else {
-        callback = lodash.createCallback(callback, thisArg, 3);
-        forIn(object, function(value, key, object) {
-          if (callback(value, key, object)) {
-            result[key] = value;
-          }
-        });
+    /**
+     * This method is like `_.xor` except that it accepts `iteratee` which is
+     * invoked for each element of each `arrays` to generate the criterion by
+     * which by which they're compared. The order of result values is determined
+     * by the order they occur in the arrays. The iteratee is invoked with one
+     * argument: (value).
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Array
+     * @param {...Array} [arrays] The arrays to inspect.
+     * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+     * @returns {Array} Returns the new array of filtered values.
+     * @example
+     *
+     * _.xorBy([2.1, 1.2], [2.3, 3.4], Math.floor);
+     * // => [1.2, 3.4]
+     *
+     * // The `_.property` iteratee shorthand.
+     * _.xorBy([{ 'x': 1 }], [{ 'x': 2 }, { 'x': 1 }], 'x');
+     * // => [{ 'x': 2 }]
+     */
+    var xorBy = baseRest(function(arrays) {
+      var iteratee = last(arrays);
+      if (isArrayLikeObject(iteratee)) {
+        iteratee = undefined;
       }
-      return result;
-    }
+      return baseXor(arrayFilter(arrays, isArrayLikeObject), getIteratee(iteratee, 2));
+    });
 
     /**
-     * An alternative to `_.reduce` this method transforms `object` to a new
-     * `accumulator` object which is the result of running each of its own
-     * enumerable properties through a callback, with each callback execution
-     * potentially mutating the `accumulator` object. The callback is bound to
-     * `thisArg` and invoked with four arguments; (accumulator, value, key, object).
-     * Callbacks may exit iteration early by explicitly returning `false`.
+     * This method is like `_.xor` except that it accepts `comparator` which is
+     * invoked to compare elements of `arrays`. The order of result values is
+     * determined by the order they occur in the arrays. The comparator is invoked
+     * with two arguments: (arrVal, othVal).
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {Array|Object} object The object to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [accumulator] The custom accumulator value.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the accumulated value.
+     * @since 4.0.0
+     * @category Array
+     * @param {...Array} [arrays] The arrays to inspect.
+     * @param {Function} [comparator] The comparator invoked per element.
+     * @returns {Array} Returns the new array of filtered values.
      * @example
      *
-     * var squares = _.transform([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], function(result, num) {
-     *   num *= num;
-     *   if (num % 2) {
-     *     return result.push(num) < 3;
-     *   }
-     * });
-     * // => [1, 9, 25]
+     * var objects = [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }];
+     * var others = [{ 'x': 1, 'y': 1 }, { 'x': 1, 'y': 2 }];
      *
-     * var mapped = _.transform({ 'a': 1, 'b': 2, 'c': 3 }, function(result, num, key) {
-     *   result[key] = num * 3;
-     * });
-     * // => { 'a': 3, 'b': 6, 'c': 9 }
+     * _.xorWith(objects, others, _.isEqual);
+     * // => [{ 'x': 2, 'y': 1 }, { 'x': 1, 'y': 1 }]
      */
-    function transform(object, callback, accumulator, thisArg) {
-      var isArr = isArray(object);
-      if (accumulator == null) {
-        if (isArr) {
-          accumulator = [];
-        } else {
-          var ctor = object && object.constructor,
-              proto = ctor && ctor.prototype;
+    var xorWith = baseRest(function(arrays) {
+      var comparator = last(arrays);
+      comparator = typeof comparator == 'function' ? comparator : undefined;
+      return baseXor(arrayFilter(arrays, isArrayLikeObject), undefined, comparator);
+    });
 
-          accumulator = baseCreate(proto);
-        }
-      }
-      if (callback) {
-        callback = lodash.createCallback(callback, thisArg, 4);
-        (isArr ? baseEach : forOwn)(object, function(value, index, object) {
-          return callback(accumulator, value, index, object);
-        });
-      }
-      return accumulator;
+    /**
+     * Creates an array of grouped elements, the first of which contains the
+     * first elements of the given arrays, the second of which contains the
+     * second elements of the given arrays, and so on.
+     *
+     * @static
+     * @memberOf _
+     * @since 0.1.0
+     * @category Array
+     * @param {...Array} [arrays] The arrays to process.
+     * @returns {Array} Returns the new array of grouped elements.
+     * @example
+     *
+     * _.zip(['a', 'b'], [1, 2], [true, false]);
+     * // => [['a', 1, true], ['b', 2, false]]
+     */
+    var zip = baseRest(unzip);
+
+    /**
+     * This method is like `_.fromPairs` except that it accepts two arrays,
+     * one of property identifiers and one of corresponding values.
+     *
+     * @static
+     * @memberOf _
+     * @since 0.4.0
+     * @category Array
+     * @param {Array} [props=[]] The property identifiers.
+     * @param {Array} [values=[]] The property values.
+     * @returns {Object} Returns the new object.
+     * @example
+     *
+     * _.zipObject(['a', 'b'], [1, 2]);
+     * // => { 'a': 1, 'b': 2 }
+     */
+    function zipObject(props, values) {
+      return baseZipObject(props || [], values || [], assignValue);
     }
 
     /**
-     * Creates an array composed of the own enumerable property values of `object`.
+     * This method is like `_.zipObject` except that it supports property paths.
      *
      * @static
      * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to inspect.
-     * @returns {Array} Returns an array of property values.
+     * @since 4.1.0
+     * @category Array
+     * @param {Array} [props=[]] The property identifiers.
+     * @param {Array} [values=[]] The property values.
+     * @returns {Object} Returns the new object.
      * @example
      *
-     * _.values({ 'one': 1, 'two': 2, 'three': 3 });
-     * // => [1, 2, 3] (property order is not guaranteed across environments)
+     * _.zipObjectDeep(['a.b[0].c', 'a.b[1].d'], [1, 2]);
+     * // => { 'a': { 'b': [{ 'c': 1 }, { 'd': 2 }] } }
      */
-    function values(object) {
-      var index = -1,
-          props = keys(object),
-          length = props.length,
-          result = Array(length);
+    function zipObjectDeep(props, values) {
+      return baseZipObject(props || [], values || [], baseSet);
+    }
 
-      while (++index < length) {
-        result[index] = object[props[index]];
-      }
+    /**
+     * This method is like `_.zip` except that it accepts `iteratee` to specify
+     * how grouped values should be combined. The iteratee is invoked with the
+     * elements of each group: (...group).
+     *
+     * @static
+     * @memberOf _
+     * @since 3.8.0
+     * @category Array
+     * @param {...Array} [arrays] The arrays to process.
+     * @param {Function} [iteratee=_.identity] The function to combine
+     *  grouped values.
+     * @returns {Array} Returns the new array of grouped elements.
+     * @example
+     *
+     * _.zipWith([1, 2], [10, 20], [100, 200], function(a, b, c) {
+     *   return a + b + c;
+     * });
+     * // => [111, 222]
+     */
+    var zipWith = baseRest(function(arrays) {
+      var length = arrays.length,
+          iteratee = length > 1 ? arrays[length - 1] : undefined;
+
+      iteratee = typeof iteratee == 'function' ? (arrays.pop(), iteratee) : undefined;
+      return unzipWith(arrays, iteratee);
+    });
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates a `lodash` wrapper instance that wraps `value` with explicit method
+     * chain sequences enabled. The result of such sequences must be unwrapped
+     * with `_#value`.
+     *
+     * @static
+     * @memberOf _
+     * @since 1.3.0
+     * @category Seq
+     * @param {*} value The value to wrap.
+     * @returns {Object} Returns the new `lodash` wrapper instance.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney',  'age': 36 },
+     *   { 'user': 'fred',    'age': 40 },
+     *   { 'user': 'pebbles', 'age': 1 }
+     * ];
+     *
+     * var youngest = _
+     *   .chain(users)
+     *   .sortBy('age')
+     *   .map(function(o) {
+     *     return o.user + ' is ' + o.age;
+     *   })
+     *   .head()
+     *   .value();
+     * // => 'pebbles is 1'
+     */
+    function chain(value) {
+      var result = lodash(value);
+      result.__chain__ = true;
       return result;
     }
 
-    /*--------------------------------------------------------------------------*/
+    /**
+     * This method invokes `interceptor` and returns `value`. The interceptor
+     * is invoked with one argument; (value). The purpose of this method is to
+     * "tap into" a method chain sequence in order to modify intermediate results.
+     *
+     * @static
+     * @memberOf _
+     * @since 0.1.0
+     * @category Seq
+     * @param {*} value The value to provide to `interceptor`.
+     * @param {Function} interceptor The function to invoke.
+     * @returns {*} Returns `value`.
+     * @example
+     *
+     * _([1, 2, 3])
+     *  .tap(function(array) {
+     *    // Mutate input array.
+     *    array.pop();
+     *  })
+     *  .reverse()
+     *  .value();
+     * // => [2, 1]
+     */
+    function tap(value, interceptor) {
+      interceptor(value);
+      return value;
+    }
 
     /**
-     * Creates an array of elements from the specified indexes, or keys, of the
-     * `collection`. Indexes may be specified as individual arguments or as arrays
-     * of indexes.
+     * This method is like `_.tap` except that it returns the result of `interceptor`.
+     * The purpose of this method is to "pass thru" values replacing intermediate
+     * results in a method chain sequence.
      *
      * @static
      * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {...(number|number[]|string|string[])} [index] The indexes of `collection`
-     *   to retrieve, specified as individual indexes or arrays of indexes.
-     * @returns {Array} Returns a new array of elements corresponding to the
-     *  provided indexes.
+     * @since 3.0.0
+     * @category Seq
+     * @param {*} value The value to provide to `interceptor`.
+     * @param {Function} interceptor The function to invoke.
+     * @returns {*} Returns the result of `interceptor`.
      * @example
      *
-     * _.at(['a', 'b', 'c', 'd', 'e'], [0, 2, 4]);
-     * // => ['a', 'c', 'e']
+     * _('  abc  ')
+     *  .chain()
+     *  .trim()
+     *  .thru(function(value) {
+     *    return [value];
+     *  })
+     *  .value();
+     * // => ['abc']
+     */
+    function thru(value, interceptor) {
+      return interceptor(value);
+    }
+
+    /**
+     * This method is the wrapper version of `_.at`.
+     *
+     * @name at
+     * @memberOf _
+     * @since 1.0.0
+     * @category Seq
+     * @param {...(string|string[])} [paths] The property paths to pick.
+     * @returns {Object} Returns the new `lodash` wrapper instance.
+     * @example
+     *
+     * var object = { 'a': [{ 'b': { 'c': 3 } }, 4] };
      *
-     * _.at(['fred', 'barney', 'pebbles'], 0, 2);
-     * // => ['fred', 'pebbles']
+     * _(object).at(['a[0].b.c', 'a[1]']).value();
+     * // => [3, 4]
      */
-    function at(collection) {
-      var args = arguments,
-          index = -1,
-          props = baseFlatten(args, true, false, 1),
-          length = (args[2] && args[2][args[1]] === collection) ? 1 : props.length,
-          result = Array(length);
+    var wrapperAt = flatRest(function(paths) {
+      var length = paths.length,
+          start = length ? paths[0] : 0,
+          value = this.__wrapped__,
+          interceptor = function(object) { return baseAt(object, paths); };
 
-      if (support.unindexedChars && isString(collection)) {
-        collection = collection.split('');
+      if (length > 1 || this.__actions__.length ||
+          !(value instanceof LazyWrapper) || !isIndex(start)) {
+        return this.thru(interceptor);
       }
-      while(++index < length) {
-        result[index] = collection[props[index]];
+      value = value.slice(start, +start + (length ? 1 : 0));
+      value.__actions__.push({
+        'func': thru,
+        'args': [interceptor],
+        'thisArg': undefined
+      });
+      return new LodashWrapper(value, this.__chain__).thru(function(array) {
+        if (length && !array.length) {
+          array.push(undefined);
+        }
+        return array;
+      });
+    });
+
+    /**
+     * Creates a `lodash` wrapper instance with explicit method chain sequences enabled.
+     *
+     * @name chain
+     * @memberOf _
+     * @since 0.1.0
+     * @category Seq
+     * @returns {Object} Returns the new `lodash` wrapper instance.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney', 'age': 36 },
+     *   { 'user': 'fred',   'age': 40 }
+     * ];
+     *
+     * // A sequence without explicit chaining.
+     * _(users).head();
+     * // => { 'user': 'barney', 'age': 36 }
+     *
+     * // A sequence with explicit chaining.
+     * _(users)
+     *   .chain()
+     *   .head()
+     *   .pick('user')
+     *   .value();
+     * // => { 'user': 'barney' }
+     */
+    function wrapperChain() {
+      return chain(this);
+    }
+
+    /**
+     * Executes the chain sequence and returns the wrapped result.
+     *
+     * @name commit
+     * @memberOf _
+     * @since 3.2.0
+     * @category Seq
+     * @returns {Object} Returns the new `lodash` wrapper instance.
+     * @example
+     *
+     * var array = [1, 2];
+     * var wrapped = _(array).push(3);
+     *
+     * console.log(array);
+     * // => [1, 2]
+     *
+     * wrapped = wrapped.commit();
+     * console.log(array);
+     * // => [1, 2, 3]
+     *
+     * wrapped.last();
+     * // => 3
+     *
+     * console.log(array);
+     * // => [1, 2, 3]
+     */
+    function wrapperCommit() {
+      return new LodashWrapper(this.value(), this.__chain__);
+    }
+
+    /**
+     * Gets the next value on a wrapped object following the
+     * [iterator protocol](https://mdn.io/iteration_protocols#iterator).
+     *
+     * @name next
+     * @memberOf _
+     * @since 4.0.0
+     * @category Seq
+     * @returns {Object} Returns the next iterator value.
+     * @example
+     *
+     * var wrapped = _([1, 2]);
+     *
+     * wrapped.next();
+     * // => { 'done': false, 'value': 1 }
+     *
+     * wrapped.next();
+     * // => { 'done': false, 'value': 2 }
+     *
+     * wrapped.next();
+     * // => { 'done': true, 'value': undefined }
+     */
+    function wrapperNext() {
+      if (this.__values__ === undefined) {
+        this.__values__ = toArray(this.value());
       }
-      return result;
+      var done = this.__index__ >= this.__values__.length,
+          value = done ? undefined : this.__values__[this.__index__++];
+
+      return { 'done': done, 'value': value };
     }
 
     /**
-     * Checks if a given value is present in a collection using strict equality
-     * for comparisons, i.e. `===`. If `fromIndex` is negative, it is used as the
-     * offset from the end of the collection.
+     * Enables the wrapper to be iterable.
      *
-     * @static
+     * @name Symbol.iterator
      * @memberOf _
-     * @alias include
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {*} target The value to check for.
-     * @param {number} [fromIndex=0] The index to search from.
-     * @returns {boolean} Returns `true` if the `target` element is found, else `false`.
+     * @since 4.0.0
+     * @category Seq
+     * @returns {Object} Returns the wrapper object.
      * @example
      *
-     * _.contains([1, 2, 3], 1);
+     * var wrapped = _([1, 2]);
+     *
+     * wrapped[Symbol.iterator]() === wrapped;
      * // => true
      *
-     * _.contains([1, 2, 3], 1, 2);
-     * // => false
+     * Array.from(wrapped);
+     * // => [1, 2]
+     */
+    function wrapperToIterator() {
+      return this;
+    }
+
+    /**
+     * Creates a clone of the chain sequence planting `value` as the wrapped value.
      *
-     * _.contains({ 'name': 'fred', 'age': 40 }, 'fred');
-     * // => true
+     * @name plant
+     * @memberOf _
+     * @since 3.2.0
+     * @category Seq
+     * @param {*} value The value to plant.
+     * @returns {Object} Returns the new `lodash` wrapper instance.
+     * @example
      *
-     * _.contains('pebbles', 'eb');
-     * // => true
+     * function square(n) {
+     *   return n * n;
+     * }
+     *
+     * var wrapped = _([1, 2]).map(square);
+     * var other = wrapped.plant([3, 4]);
+     *
+     * other.value();
+     * // => [9, 16]
+     *
+     * wrapped.value();
+     * // => [1, 4]
      */
-    function contains(collection, target, fromIndex) {
-      var index = -1,
-          indexOf = getIndexOf(),
-          length = collection ? collection.length : 0,
-          result = false;
+    function wrapperPlant(value) {
+      var result,
+          parent = this;
+
+      while (parent instanceof baseLodash) {
+        var clone = wrapperClone(parent);
+        clone.__index__ = 0;
+        clone.__values__ = undefined;
+        if (result) {
+          previous.__wrapped__ = clone;
+        } else {
+          result = clone;
+        }
+        var previous = clone;
+        parent = parent.__wrapped__;
+      }
+      previous.__wrapped__ = value;
+      return result;
+    }
 
-      fromIndex = (fromIndex < 0 ? nativeMax(0, length + fromIndex) : fromIndex) || 0;
-      if (isArray(collection)) {
-        result = indexOf(collection, target, fromIndex) > -1;
-      } else if (typeof length == 'number') {
-        result = (isString(collection) ? collection.indexOf(target, fromIndex) : indexOf(collection, target, fromIndex)) > -1;
-      } else {
-        baseEach(collection, function(value) {
-          if (++index >= fromIndex) {
-            return !(result = value === target);
-          }
+    /**
+     * This method is the wrapper version of `_.reverse`.
+     *
+     * **Note:** This method mutates the wrapped array.
+     *
+     * @name reverse
+     * @memberOf _
+     * @since 0.1.0
+     * @category Seq
+     * @returns {Object} Returns the new `lodash` wrapper instance.
+     * @example
+     *
+     * var array = [1, 2, 3];
+     *
+     * _(array).reverse().value()
+     * // => [3, 2, 1]
+     *
+     * console.log(array);
+     * // => [3, 2, 1]
+     */
+    function wrapperReverse() {
+      var value = this.__wrapped__;
+      if (value instanceof LazyWrapper) {
+        var wrapped = value;
+        if (this.__actions__.length) {
+          wrapped = new LazyWrapper(this);
+        }
+        wrapped = wrapped.reverse();
+        wrapped.__actions__.push({
+          'func': thru,
+          'args': [reverse],
+          'thisArg': undefined
         });
+        return new LodashWrapper(wrapped, this.__chain__);
       }
-      return result;
+      return this.thru(reverse);
     }
 
     /**
-     * Creates an object composed of keys generated from the results of running
-     * each element of `collection` through the callback. The corresponding value
-     * of each key is the number of times the key was returned by the callback.
-     * The callback is bound to `thisArg` and invoked with three arguments;
-     * (value, index|key, collection).
+     * Executes the chain sequence to resolve the unwrapped value.
      *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
+     * @name value
+     * @memberOf _
+     * @since 0.1.0
+     * @alias toJSON, valueOf
+     * @category Seq
+     * @returns {*} Returns the resolved unwrapped value.
+     * @example
      *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * _([1, 2, 3]).value();
+     * // => [1, 2, 3]
+     */
+    function wrapperValue() {
+      return baseWrapperValue(this.__wrapped__, this.__actions__);
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates an object composed of keys generated from the results of running
+     * each element of `collection` thru `iteratee`. The corresponding value of
+     * each key is the number of times the key was returned by `iteratee`. The
+     * iteratee is invoked with one argument: (value).
      *
      * @static
      * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
+     * @since 0.5.0
+     * @category Collection
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function} [iteratee=_.identity] The iteratee to transform keys.
      * @returns {Object} Returns the composed aggregate object.
      * @example
      *
-     * _.countBy([4.3, 6.1, 6.4], function(num) { return Math.floor(num); });
-     * // => { '4': 1, '6': 2 }
-     *
-     * _.countBy([4.3, 6.1, 6.4], function(num) { return this.floor(num); }, Math);
+     * _.countBy([6.1, 4.2, 6.3], Math.floor);
      * // => { '4': 1, '6': 2 }
      *
+     * // The `_.property` iteratee shorthand.
      * _.countBy(['one', 'two', 'three'], 'length');
      * // => { '3': 2, '5': 1 }
      */
     var countBy = createAggregator(function(result, value, key) {
-      (hasOwnProperty.call(result, key) ? result[key]++ : result[key] = 1);
+      if (hasOwnProperty.call(result, key)) {
+        ++result[key];
+      } else {
+        baseAssignValue(result, key, 1);
+      }
     });
 
     /**
-     * Checks if the given callback returns truey value for **all** elements of
-     * a collection. The callback is bound to `thisArg` and invoked with three
-     * arguments; (value, index|key, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * Checks if `predicate` returns truthy for **all** elements of `collection`.
+     * Iteration is stopped once `predicate` returns falsey. The predicate is
+     * invoked with three arguments: (value, index|key, collection).
+     *
+     * **Note:** This method returns `true` for
+     * [empty collections](https://en.wikipedia.org/wiki/Empty_set) because
+     * [everything is true](https://en.wikipedia.org/wiki/Vacuous_truth) of
+     * elements of empty collections.
      *
      * @static
      * @memberOf _
-     * @alias all
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {boolean} Returns `true` if all elements passed the callback check,
+     * @since 0.1.0
+     * @category Collection
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function} [predicate=_.identity] The function invoked per iteration.
+     * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
+     * @returns {boolean} Returns `true` if all elements pass the predicate check,
      *  else `false`.
      * @example
      *
-     * _.every([true, 1, null, 'yes']);
+     * _.every([true, 1, null, 'yes'], Boolean);
      * // => false
      *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
+     * var users = [
+     *   { 'user': 'barney', 'age': 36, 'active': false },
+     *   { 'user': 'fred',   'age': 40, 'active': false }
      * ];
      *
-     * // using "_.pluck" callback shorthand
-     * _.every(characters, 'age');
+     * // The `_.matches` iteratee shorthand.
+     * _.every(users, { 'user': 'barney', 'active': false });
+     * // => false
+     *
+     * // The `_.matchesProperty` iteratee shorthand.
+     * _.every(users, ['active', false]);
      * // => true
      *
-     * // using "_.where" callback shorthand
-     * _.every(characters, { 'age': 36 });
+     * // The `_.property` iteratee shorthand.
+     * _.every(users, 'active');
      * // => false
      */
-    function every(collection, callback, thisArg) {
-      var result = true;
-      callback = lodash.createCallback(callback, thisArg, 3);
-
-      if (isArray(collection)) {
-        var index = -1,
-            length = collection.length;
-
-        while (++index < length) {
-          if (!(result = !!callback(collection[index], index, collection))) {
-            break;
-          }
-        }
-      } else {
-        baseEach(collection, function(value, index, collection) {
-          return (result = !!callback(value, index, collection));
-        });
+    function every(collection, predicate, guard) {
+      var func = isArray(collection) ? arrayEvery : baseEvery;
+      if (guard && isIterateeCall(collection, predicate, guard)) {
+        predicate = undefined;
       }
-      return result;
+      return func(collection, getIteratee(predicate, 3));
     }
 
     /**
-     * Iterates over elements of a collection, returning an array of all elements
-     * the callback returns truey for. The callback is bound to `thisArg` and
-     * invoked with three arguments; (value, index|key, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
+     * Iterates over elements of `collection`, returning an array of all elements
+     * `predicate` returns truthy for. The predicate is invoked with three
+     * arguments: (value, index|key, collection).
      *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * **Note:** Unlike `_.remove`, this method returns a new array.
      *
      * @static
      * @memberOf _
-     * @alias select
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a new array of elements that passed the callback check.
+     * @since 0.1.0
+     * @category Collection
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function} [predicate=_.identity] The function invoked per iteration.
+     * @returns {Array} Returns the new filtered array.
+     * @see _.reject
      * @example
      *
-     * var evens = _.filter([1, 2, 3, 4, 5, 6], function(num) { return num % 2 == 0; });
-     * // => [2, 4, 6]
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36, 'blocked': false },
-     *   { 'name': 'fred',   'age': 40, 'blocked': true }
+     * var users = [
+     *   { 'user': 'barney', 'age': 36, 'active': true },
+     *   { 'user': 'fred',   'age': 40, 'active': false }
      * ];
      *
-     * // using "_.pluck" callback shorthand
-     * _.filter(characters, 'blocked');
-     * // => [{ 'name': 'fred', 'age': 40, 'blocked': true }]
-     *
-     * // using "_.where" callback shorthand
-     * _.filter(characters, { 'age': 36 });
-     * // => [{ 'name': 'barney', 'age': 36, 'blocked': false }]
+     * _.filter(users, function(o) { return !o.active; });
+     * // => objects for ['fred']
+     *
+     * // The `_.matches` iteratee shorthand.
+     * _.filter(users, { 'age': 36, 'active': true });
+     * // => objects for ['barney']
+     *
+     * // The `_.matchesProperty` iteratee shorthand.
+     * _.filter(users, ['active', false]);
+     * // => objects for ['fred']
+     *
+     * // The `_.property` iteratee shorthand.
+     * _.filter(users, 'active');
+     * // => objects for ['barney']
+     *
+     * // Combining several predicates using `_.overEvery` or `_.overSome`.
+     * _.filter(users, _.overSome([{ 'age': 36 }, ['age', 40]]));
+     * // => objects for ['fred', 'barney']
      */
-    function filter(collection, callback, thisArg) {
-      var result = [];
-      callback = lodash.createCallback(callback, thisArg, 3);
-
-      if (isArray(collection)) {
-        var index = -1,
-            length = collection.length;
-
-        while (++index < length) {
-          var value = collection[index];
-          if (callback(value, index, collection)) {
-            result.push(value);
-          }
-        }
-      } else {
-        baseEach(collection, function(value, index, collection) {
-          if (callback(value, index, collection)) {
-            result.push(value);
-          }
-        });
-      }
-      return result;
+    function filter(collection, predicate) {
+      var func = isArray(collection) ? arrayFilter : baseFilter;
+      return func(collection, getIteratee(predicate, 3));
     }
 
     /**
-     * Iterates over elements of a collection, returning the first element that
-     * the callback returns truey for. The callback is bound to `thisArg` and
-     * invoked with three arguments; (value, index|key, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * Iterates over elements of `collection`, returning the first element
+     * `predicate` returns truthy for. The predicate is invoked with three
+     * arguments: (value, index|key, collection).
      *
      * @static
      * @memberOf _
-     * @alias detect, findWhere
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the found element, else `undefined`.
+     * @since 0.1.0
+     * @category Collection
+     * @param {Array|Object} collection The collection to inspect.
+     * @param {Function} [predicate=_.identity] The function invoked per iteration.
+     * @param {number} [fromIndex=0] The index to search from.
+     * @returns {*} Returns the matched element, else `undefined`.
      * @example
      *
-     * var characters = [
-     *   { 'name': 'barney',  'age': 36, 'blocked': false },
-     *   { 'name': 'fred',    'age': 40, 'blocked': true },
-     *   { 'name': 'pebbles', 'age': 1,  'blocked': false }
+     * var users = [
+     *   { 'user': 'barney',  'age': 36, 'active': true },
+     *   { 'user': 'fred',    'age': 40, 'active': false },
+     *   { 'user': 'pebbles', 'age': 1,  'active': true }
      * ];
      *
-     * _.find(characters, function(chr) {
-     *   return chr.age < 40;
-     * });
-     * // => { 'name': 'barney', 'age': 36, 'blocked': false }
+     * _.find(users, function(o) { return o.age < 40; });
+     * // => object for 'barney'
+     *
+     * // The `_.matches` iteratee shorthand.
+     * _.find(users, { 'age': 1, 'active': true });
+     * // => object for 'pebbles'
      *
-     * // using "_.where" callback shorthand
-     * _.find(characters, { 'age': 1 });
-     * // =>  { 'name': 'pebbles', 'age': 1, 'blocked': false }
+     * // The `_.matchesProperty` iteratee shorthand.
+     * _.find(users, ['active', false]);
+     * // => object for 'fred'
      *
-     * // using "_.pluck" callback shorthand
-     * _.find(characters, 'blocked');
-     * // => { 'name': 'fred', 'age': 40, 'blocked': true }
+     * // The `_.property` iteratee shorthand.
+     * _.find(users, 'active');
+     * // => object for 'barney'
      */
-    function find(collection, callback, thisArg) {
-      callback = lodash.createCallback(callback, thisArg, 3);
+    var find = createFind(findIndex);
 
-      if (isArray(collection)) {
-        var index = -1,
-            length = collection.length;
+    /**
+     * This method is like `_.find` except that it iterates over elements of
+     * `collection` from right to left.
+     *
+     * @static
+     * @memberOf _
+     * @since 2.0.0
+     * @category Collection
+     * @param {Array|Object} collection The collection to inspect.
+     * @param {Function} [predicate=_.identity] The function invoked per iteration.
+     * @param {number} [fromIndex=collection.length-1] The index to search from.
+     * @returns {*} Returns the matched element, else `undefined`.
+     * @example
+     *
+     * _.findLast([1, 2, 3, 4], function(n) {
+     *   return n % 2 == 1;
+     * });
+     * // => 3
+     */
+    var findLast = createFind(findLastIndex);
 
-        while (++index < length) {
-          var value = collection[index];
-          if (callback(value, index, collection)) {
-            return value;
-          }
-        }
-      } else {
-        var result;
-        baseEach(collection, function(value, index, collection) {
-          if (callback(value, index, collection)) {
-            result = value;
-            return false;
-          }
-        });
-        return result;
-      }
+    /**
+     * Creates a flattened array of values by running each element in `collection`
+     * thru `iteratee` and flattening the mapped results. The iteratee is invoked
+     * with three arguments: (value, index|key, collection).
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Collection
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @returns {Array} Returns the new flattened array.
+     * @example
+     *
+     * function duplicate(n) {
+     *   return [n, n];
+     * }
+     *
+     * _.flatMap([1, 2], duplicate);
+     * // => [1, 1, 2, 2]
+     */
+    function flatMap(collection, iteratee) {
+      return baseFlatten(map(collection, iteratee), 1);
     }
 
     /**
-     * This method is like `_.find` except that it iterates over elements
-     * of a `collection` from right to left.
+     * This method is like `_.flatMap` except that it recursively flattens the
+     * mapped results.
      *
      * @static
      * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the found element, else `undefined`.
+     * @since 4.7.0
+     * @category Collection
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @returns {Array} Returns the new flattened array.
      * @example
      *
-     * _.findLast([1, 2, 3, 4], function(num) {
-     *   return num % 2 == 1;
-     * });
-     * // => 3
+     * function duplicate(n) {
+     *   return [[[n, n]]];
+     * }
+     *
+     * _.flatMapDeep([1, 2], duplicate);
+     * // => [1, 1, 2, 2]
      */
-    function findLast(collection, callback, thisArg) {
-      var result;
-      callback = lodash.createCallback(callback, thisArg, 3);
-      forEachRight(collection, function(value, index, collection) {
-        if (callback(value, index, collection)) {
-          result = value;
-          return false;
-        }
-      });
-      return result;
+    function flatMapDeep(collection, iteratee) {
+      return baseFlatten(map(collection, iteratee), INFINITY);
     }
 
     /**
-     * Iterates over elements of a collection, executing the callback for each
-     * element. The callback is bound to `thisArg` and invoked with three arguments;
-     * (value, index|key, collection). Callbacks may exit iteration early by
-     * explicitly returning `false`.
-     *
-     * Note: As with other "Collections" methods, objects with a `length` property
-     * are iterated like arrays. To avoid this behavior `_.forIn` or `_.forOwn`
-     * may be used for object iteration.
+     * This method is like `_.flatMap` except that it recursively flattens the
+     * mapped results up to `depth` times.
      *
      * @static
      * @memberOf _
-     * @alias each
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array|Object|string} Returns `collection`.
+     * @since 4.7.0
+     * @category Collection
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {number} [depth=1] The maximum recursion depth.
+     * @returns {Array} Returns the new flattened array.
      * @example
      *
-     * _([1, 2, 3]).forEach(function(num) { console.log(num); }).join(',');
-     * // => logs each number and returns '1,2,3'
+     * function duplicate(n) {
+     *   return [[[n, n]]];
+     * }
      *
-     * _.forEach({ 'one': 1, 'two': 2, 'three': 3 }, function(num) { console.log(num); });
-     * // => logs each number and returns the object (property order is not guaranteed across environments)
+     * _.flatMapDepth([1, 2], duplicate, 2);
+     * // => [[1, 1], [2, 2]]
      */
-    function forEach(collection, callback, thisArg) {
-      if (callback && typeof thisArg == 'undefined' && isArray(collection)) {
-        var index = -1,
-            length = collection.length;
+    function flatMapDepth(collection, iteratee, depth) {
+      depth = depth === undefined ? 1 : toInteger(depth);
+      return baseFlatten(map(collection, iteratee), depth);
+    }
 
-        while (++index < length) {
-          if (callback(collection[index], index, collection) === false) {
-            break;
-          }
-        }
-      } else {
-        baseEach(collection, callback, thisArg);
-      }
-      return collection;
+    /**
+     * Iterates over elements of `collection` and invokes `iteratee` for each element.
+     * The iteratee is invoked with three arguments: (value, index|key, collection).
+     * Iteratee functions may exit iteration early by explicitly returning `false`.
+     *
+     * **Note:** As with other "Collections" methods, objects with a "length"
+     * property are iterated like arrays. To avoid this behavior use `_.forIn`
+     * or `_.forOwn` for object iteration.
+     *
+     * @static
+     * @memberOf _
+     * @since 0.1.0
+     * @alias each
+     * @category Collection
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @returns {Array|Object} Returns `collection`.
+     * @see _.forEachRight
+     * @example
+     *
+     * _.forEach([1, 2], function(value) {
+     *   console.log(value);
+     * });
+     * // => Logs `1` then `2`.
+     *
+     * _.forEach({ 'a': 1, 'b': 2 }, function(value, key) {
+     *   console.log(key);
+     * });
+     * // => Logs 'a' then 'b' (iteration order is not guaranteed).
+     */
+    function forEach(collection, iteratee) {
+      var func = isArray(collection) ? arrayEach : baseEach;
+      return func(collection, getIteratee(iteratee, 3));
     }
 
     /**
-     * This method is like `_.forEach` except that it iterates over elements
-     * of a `collection` from right to left.
+     * This method is like `_.forEach` except that it iterates over elements of
+     * `collection` from right to left.
      *
      * @static
      * @memberOf _
+     * @since 2.0.0
      * @alias eachRight
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array|Object|string} Returns `collection`.
-     * @example
-     *
-     * _([1, 2, 3]).forEachRight(function(num) { console.log(num); }).join(',');
-     * // => logs each number from right to left and returns '3,2,1'
-     */
-    function forEachRight(collection, callback, thisArg) {
-      var iterable = collection,
-          length = collection ? collection.length : 0;
-
-      callback = callback && typeof thisArg == 'undefined' ? callback : baseCreateCallback(callback, thisArg, 3);
-      if (isArray(collection)) {
-        while (length--) {
-          if (callback(collection[length], length, collection) === false) {
-            break;
-          }
-        }
-      } else {
-        if (typeof length != 'number') {
-          var props = keys(collection);
-          length = props.length;
-        } else if (support.unindexedChars && isString(collection)) {
-          iterable = collection.split('');
-        }
-        baseEach(collection, function(value, key, collection) {
-          key = props ? props[--length] : --length;
-          return callback(iterable[key], key, collection);
-        });
-      }
-      return collection;
+     * @category Collection
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @returns {Array|Object} Returns `collection`.
+     * @see _.forEach
+     * @example
+     *
+     * _.forEachRight([1, 2], function(value) {
+     *   console.log(value);
+     * });
+     * // => Logs `2` then `1`.
+     */
+    function forEachRight(collection, iteratee) {
+      var func = isArray(collection) ? arrayEachRight : baseEachRight;
+      return func(collection, getIteratee(iteratee, 3));
     }
 
     /**
      * Creates an object composed of keys generated from the results of running
-     * each element of a collection through the callback. The corresponding value
-     * of each key is an array of the elements responsible for generating the key.
-     * The callback is bound to `thisArg` and invoked with three arguments;
-     * (value, index|key, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`
+     * each element of `collection` thru `iteratee`. The order of grouped values
+     * is determined by the order they occur in `collection`. The corresponding
+     * value of each key is an array of elements responsible for generating the
+     * key. The iteratee is invoked with one argument: (value).
      *
      * @static
      * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
+     * @since 0.1.0
+     * @category Collection
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function} [iteratee=_.identity] The iteratee to transform keys.
      * @returns {Object} Returns the composed aggregate object.
      * @example
      *
-     * _.groupBy([4.2, 6.1, 6.4], function(num) { return Math.floor(num); });
-     * // => { '4': [4.2], '6': [6.1, 6.4] }
-     *
-     * _.groupBy([4.2, 6.1, 6.4], function(num) { return this.floor(num); }, Math);
-     * // => { '4': [4.2], '6': [6.1, 6.4] }
+     * _.groupBy([6.1, 4.2, 6.3], Math.floor);
+     * // => { '4': [4.2], '6': [6.1, 6.3] }
      *
-     * // using "_.pluck" callback shorthand
+     * // The `_.property` iteratee shorthand.
      * _.groupBy(['one', 'two', 'three'], 'length');
      * // => { '3': ['one', 'two'], '5': ['three'] }
      */
     var groupBy = createAggregator(function(result, value, key) {
-      (hasOwnProperty.call(result, key) ? result[key] : result[key] = []).push(value);
+      if (hasOwnProperty.call(result, key)) {
+        result[key].push(value);
+      } else {
+        baseAssignValue(result, key, [value]);
+      }
     });
 
     /**
-     * Creates an object composed of keys generated from the results of running
-     * each element of the collection through the given callback. The corresponding
-     * value of each key is the last element responsible for generating the key.
-     * The callback is bound to `thisArg` and invoked with three arguments;
-     * (value, index|key, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * Checks if `value` is in `collection`. If `collection` is a string, it's
+     * checked for a substring of `value`, otherwise
+     * [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
+     * is used for equality comparisons. If `fromIndex` is negative, it's used as
+     * the offset from the end of `collection`.
      *
      * @static
      * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns the composed aggregate object.
+     * @since 0.1.0
+     * @category Collection
+     * @param {Array|Object|string} collection The collection to inspect.
+     * @param {*} value The value to search for.
+     * @param {number} [fromIndex=0] The index to search from.
+     * @param- {Object} [guard] Enables use as an iteratee for methods like `_.reduce`.
+     * @returns {boolean} Returns `true` if `value` is found, else `false`.
      * @example
      *
-     * var keys = [
-     *   { 'dir': 'left', 'code': 97 },
-     *   { 'dir': 'right', 'code': 100 }
-     * ];
+     * _.includes([1, 2, 3], 1);
+     * // => true
      *
-     * _.indexBy(keys, 'dir');
-     * // => { 'left': { 'dir': 'left', 'code': 97 }, 'right': { 'dir': 'right', 'code': 100 } }
+     * _.includes([1, 2, 3], 1, 2);
+     * // => false
      *
-     * _.indexBy(keys, function(key) { return String.fromCharCode(key.code); });
-     * // => { 'a': { 'dir': 'left', 'code': 97 }, 'd': { 'dir': 'right', 'code': 100 } }
+     * _.includes({ 'a': 1, 'b': 2 }, 1);
+     * // => true
      *
-     * _.indexBy(characters, function(key) { this.fromCharCode(key.code); }, String);
-     * // => { 'a': { 'dir': 'left', 'code': 97 }, 'd': { 'dir': 'right', 'code': 100 } }
+     * _.includes('abcd', 'bc');
+     * // => true
      */
-    var indexBy = createAggregator(function(result, value, key) {
-      result[key] = value;
-    });
+    function includes(collection, value, fromIndex, guard) {
+      collection = isArrayLike(collection) ? collection : values(collection);
+      fromIndex = (fromIndex && !guard) ? toInteger(fromIndex) : 0;
+
+      var length = collection.length;
+      if (fromIndex < 0) {
+        fromIndex = nativeMax(length + fromIndex, 0);
+      }
+      return isString(collection)
+        ? (fromIndex <= length && collection.indexOf(value, fromIndex) > -1)
+        : (!!length && baseIndexOf(collection, value, fromIndex) > -1);
+    }
 
     /**
-     * Invokes the method named by `methodName` on each element in the `collection`
-     * returning an array of the results of each invoked method. Additional arguments
-     * will be provided to each invoked method. If `methodName` is a function it
-     * will be invoked for, and `this` bound to, each element in the `collection`.
+     * Invokes the method at `path` of each element in `collection`, returning
+     * an array of the results of each invoked method. Any additional arguments
+     * are provided to each invoked method. If `path` is a function, it's invoked
+     * for, and `this` bound to, each element in `collection`.
      *
      * @static
      * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|string} methodName The name of the method to invoke or
+     * @since 4.0.0
+     * @category Collection
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Array|Function|string} path The path of the method to invoke or
      *  the function invoked per iteration.
-     * @param {...*} [arg] Arguments to invoke the method with.
-     * @returns {Array} Returns a new array of the results of each invoked method.
+     * @param {...*} [args] The arguments to invoke each method with.
+     * @returns {Array} Returns the array of results.
      * @example
      *
-     * _.invoke([[5, 1, 7], [3, 2, 1]], 'sort');
+     * _.invokeMap([[5, 1, 7], [3, 2, 1]], 'sort');
      * // => [[1, 5, 7], [1, 2, 3]]
      *
-     * _.invoke([123, 456], String.prototype.split, '');
+     * _.invokeMap([123, 456], String.prototype.split, '');
      * // => [['1', '2', '3'], ['4', '5', '6']]
      */
-    function invoke(collection, methodName) {
-      var args = slice(arguments, 2),
-          index = -1,
-          isFunc = typeof methodName == 'function',
-          length = collection ? collection.length : 0,
-          result = Array(typeof length == 'number' ? length : 0);
+    var invokeMap = baseRest(function(collection, path, args) {
+      var index = -1,
+          isFunc = typeof path == 'function',
+          result = isArrayLike(collection) ? Array(collection.length) : [];
 
-      forEach(collection, function(value) {
-        result[++index] = (isFunc ? methodName : value[methodName]).apply(value, args);
+      baseEach(collection, function(value) {
+        result[++index] = isFunc ? apply(path, value, args) : baseInvoke(value, path, args);
       });
       return result;
-    }
+    });
 
     /**
-     * Creates an array of values by running each element in the collection
-     * through the callback. The callback is bound to `thisArg` and invoked with
-     * three arguments; (value, index|key, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * Creates an object composed of keys generated from the results of running
+     * each element of `collection` thru `iteratee`. The corresponding value of
+     * each key is the last element responsible for generating the key. The
+     * iteratee is invoked with one argument: (value).
      *
      * @static
      * @memberOf _
-     * @alias collect
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a new array of the results of each `callback` execution.
+     * @since 4.0.0
+     * @category Collection
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function} [iteratee=_.identity] The iteratee to transform keys.
+     * @returns {Object} Returns the composed aggregate object.
      * @example
      *
-     * _.map([1, 2, 3], function(num) { return num * 3; });
-     * // => [3, 6, 9]
-     *
-     * _.map({ 'one': 1, 'two': 2, 'three': 3 }, function(num) { return num * 3; });
-     * // => [3, 6, 9] (property order is not guaranteed across environments)
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
+     * var array = [
+     *   { 'dir': 'left', 'code': 97 },
+     *   { 'dir': 'right', 'code': 100 }
      * ];
      *
-     * // using "_.pluck" callback shorthand
-     * _.map(characters, 'name');
-     * // => ['barney', 'fred']
+     * _.keyBy(array, function(o) {
+     *   return String.fromCharCode(o.code);
+     * });
+     * // => { 'a': { 'dir': 'left', 'code': 97 }, 'd': { 'dir': 'right', 'code': 100 } }
+     *
+     * _.keyBy(array, 'dir');
+     * // => { 'left': { 'dir': 'left', 'code': 97 }, 'right': { 'dir': 'right', 'code': 100 } }
      */
-    function map(collection, callback, thisArg) {
-      var index = -1,
-          length = collection ? collection.length : 0,
-          result = Array(typeof length == 'number' ? length : 0);
-
-      callback = lodash.createCallback(callback, thisArg, 3);
-      if (isArray(collection)) {
-        while (++index < length) {
-          result[index] = callback(collection[index], index, collection);
-        }
-      } else {
-        baseEach(collection, function(value, key, collection) {
-          result[++index] = callback(value, key, collection);
-        });
-      }
-      return result;
-    }
+    var keyBy = createAggregator(function(result, value, key) {
+      baseAssignValue(result, key, value);
+    });
 
     /**
-     * Retrieves the maximum value of a collection. If the collection is empty or
-     * falsey `-Infinity` is returned. If a callback is provided it will be executed
-     * for each value in the collection to generate the criterion by which the value
-     * is ranked. The callback is bound to `thisArg` and invoked with three
-     * arguments; (value, index, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * Creates an array of values by running each element in `collection` thru
+     * `iteratee`. The iteratee is invoked with three arguments:
+     * (value, index|key, collection).
+     *
+     * Many lodash methods are guarded to work as iteratees for methods like
+     * `_.every`, `_.filter`, `_.map`, `_.mapValues`, `_.reject`, and `_.some`.
+     *
+     * The guarded methods are:
+     * `ary`, `chunk`, `curry`, `curryRight`, `drop`, `dropRight`, `every`,
+     * `fill`, `invert`, `parseInt`, `random`, `range`, `rangeRight`, `repeat`,
+     * `sampleSize`, `slice`, `some`, `sortBy`, `split`, `take`, `takeRight`,
+     * `template`, `trim`, `trimEnd`, `trimStart`, and `words`
      *
      * @static
      * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the maximum value.
+     * @since 0.1.0
+     * @category Collection
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @returns {Array} Returns the new mapped array.
      * @example
      *
-     * _.max([4, 2, 8, 6]);
-     * // => 8
+     * function square(n) {
+     *   return n * n;
+     * }
      *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
-     * ];
+     * _.map([4, 8], square);
+     * // => [16, 64]
      *
-     * _.max(characters, function(chr) { return chr.age; });
-     * // => { 'name': 'fred', 'age': 40 };
+     * _.map({ 'a': 4, 'b': 8 }, square);
+     * // => [16, 64] (iteration order is not guaranteed)
      *
-     * // using "_.pluck" callback shorthand
-     * _.max(characters, 'age');
-     * // => { 'name': 'fred', 'age': 40 };
-     */
-    function max(collection, callback, thisArg) {
-      var computed = -Infinity,
-          result = computed;
-
-      // allows working with functions like `_.map` without using
-      // their `index` argument as a callback
-      if (typeof callback != 'function' && thisArg && thisArg[callback] === collection) {
-        callback = null;
-      }
-      if (callback == null && isArray(collection)) {
-        var index = -1,
-            length = collection.length;
-
-        while (++index < length) {
-          var value = collection[index];
-          if (value > result) {
-            result = value;
-          }
-        }
-      } else {
-        callback = (callback == null && isString(collection))
-          ? charAtCallback
-          : lodash.createCallback(callback, thisArg, 3);
-
-        baseEach(collection, function(value, index, collection) {
-          var current = callback(value, index, collection);
-          if (current > computed) {
-            computed = current;
-            result = value;
-          }
-        });
-      }
-      return result;
+     * var users = [
+     *   { 'user': 'barney' },
+     *   { 'user': 'fred' }
+     * ];
+     *
+     * // The `_.property` iteratee shorthand.
+     * _.map(users, 'user');
+     * // => ['barney', 'fred']
+     */
+    function map(collection, iteratee) {
+      var func = isArray(collection) ? arrayMap : baseMap;
+      return func(collection, getIteratee(iteratee, 3));
     }
 
     /**
-     * Retrieves the minimum value of a collection. If the collection is empty or
-     * falsey `Infinity` is returned. If a callback is provided it will be executed
-     * for each value in the collection to generate the criterion by which the value
-     * is ranked. The callback is bound to `thisArg` and invoked with three
-     * arguments; (value, index, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * This method is like `_.sortBy` except that it allows specifying the sort
+     * orders of the iteratees to sort by. If `orders` is unspecified, all values
+     * are sorted in ascending order. Otherwise, specify an order of "desc" for
+     * descending or "asc" for ascending sort order of corresponding values.
      *
      * @static
      * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the minimum value.
+     * @since 4.0.0
+     * @category Collection
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Array[]|Function[]|Object[]|string[]} [iteratees=[_.identity]]
+     *  The iteratees to sort by.
+     * @param {string[]} [orders] The sort orders of `iteratees`.
+     * @param- {Object} [guard] Enables use as an iteratee for methods like `_.reduce`.
+     * @returns {Array} Returns the new sorted array.
      * @example
      *
-     * _.min([4, 2, 8, 6]);
-     * // => 2
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
+     * var users = [
+     *   { 'user': 'fred',   'age': 48 },
+     *   { 'user': 'barney', 'age': 34 },
+     *   { 'user': 'fred',   'age': 40 },
+     *   { 'user': 'barney', 'age': 36 }
      * ];
      *
-     * _.min(characters, function(chr) { return chr.age; });
-     * // => { 'name': 'barney', 'age': 36 };
-     *
-     * // using "_.pluck" callback shorthand
-     * _.min(characters, 'age');
-     * // => { 'name': 'barney', 'age': 36 };
-     */
-    function min(collection, callback, thisArg) {
-      var computed = Infinity,
-          result = computed;
-
-      // allows working with functions like `_.map` without using
-      // their `index` argument as a callback
-      if (typeof callback != 'function' && thisArg && thisArg[callback] === collection) {
-        callback = null;
+     * // Sort by `user` in ascending order and by `age` in descending order.
+     * _.orderBy(users, ['user', 'age'], ['asc', 'desc']);
+     * // => objects for [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 40]]
+     */
+    function orderBy(collection, iteratees, orders, guard) {
+      if (collection == null) {
+        return [];
       }
-      if (callback == null && isArray(collection)) {
-        var index = -1,
-            length = collection.length;
-
-        while (++index < length) {
-          var value = collection[index];
-          if (value < result) {
-            result = value;
-          }
-        }
-      } else {
-        callback = (callback == null && isString(collection))
-          ? charAtCallback
-          : lodash.createCallback(callback, thisArg, 3);
-
-        baseEach(collection, function(value, index, collection) {
-          var current = callback(value, index, collection);
-          if (current < computed) {
-            computed = current;
-            result = value;
-          }
-        });
+      if (!isArray(iteratees)) {
+        iteratees = iteratees == null ? [] : [iteratees];
       }
-      return result;
+      orders = guard ? undefined : orders;
+      if (!isArray(orders)) {
+        orders = orders == null ? [] : [orders];
+      }
+      return baseOrderBy(collection, iteratees, orders);
     }
 
     /**
-     * Retrieves the value of a specified property from all elements in the collection.
+     * Creates an array of elements split into two groups, the first of which
+     * contains elements `predicate` returns truthy for, the second of which
+     * contains elements `predicate` returns falsey for. The predicate is
+     * invoked with one argument: (value).
      *
      * @static
      * @memberOf _
-     * @type Function
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {string} property The name of the property to pluck.
-     * @returns {Array} Returns a new array of property values.
+     * @since 3.0.0
+     * @category Collection
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function} [predicate=_.identity] The function invoked per iteration.
+     * @returns {Array} Returns the array of grouped elements.
      * @example
      *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
+     * var users = [
+     *   { 'user': 'barney',  'age': 36, 'active': false },
+     *   { 'user': 'fred',    'age': 40, 'active': true },
+     *   { 'user': 'pebbles', 'age': 1,  'active': false }
      * ];
      *
-     * _.pluck(characters, 'name');
-     * // => ['barney', 'fred']
+     * _.partition(users, function(o) { return o.active; });
+     * // => objects for [['fred'], ['barney', 'pebbles']]
+     *
+     * // The `_.matches` iteratee shorthand.
+     * _.partition(users, { 'age': 1, 'active': false });
+     * // => objects for [['pebbles'], ['barney', 'fred']]
+     *
+     * // The `_.matchesProperty` iteratee shorthand.
+     * _.partition(users, ['active', false]);
+     * // => objects for [['barney', 'pebbles'], ['fred']]
+     *
+     * // The `_.property` iteratee shorthand.
+     * _.partition(users, 'active');
+     * // => objects for [['fred'], ['barney', 'pebbles']]
      */
-    var pluck = map;
+    var partition = createAggregator(function(result, value, key) {
+      result[key ? 0 : 1].push(value);
+    }, function() { return [[], []]; });
 
     /**
-     * Reduces a collection to a value which is the accumulated result of running
-     * each element in the collection through the callback, where each successive
-     * callback execution consumes the return value of the previous execution. If
-     * `accumulator` is not provided the first element of the collection will be
-     * used as the initial `accumulator` value. The callback is bound to `thisArg`
-     * and invoked with four arguments; (accumulator, value, index|key, collection).
+     * Reduces `collection` to a value which is the accumulated result of running
+     * each element in `collection` thru `iteratee`, where each successive
+     * invocation is supplied the return value of the previous. If `accumulator`
+     * is not given, the first element of `collection` is used as the initial
+     * value. The iteratee is invoked with four arguments:
+     * (accumulator, value, index|key, collection).
+     *
+     * Many lodash methods are guarded to work as iteratees for methods like
+     * `_.reduce`, `_.reduceRight`, and `_.transform`.
+     *
+     * The guarded methods are:
+     * `assign`, `defaults`, `defaultsDeep`, `includes`, `merge`, `orderBy`,
+     * and `sortBy`
      *
      * @static
      * @memberOf _
-     * @alias foldl, inject
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [accumulator] Initial value of the accumulator.
-     * @param {*} [thisArg] The `this` binding of `callback`.
+     * @since 0.1.0
+     * @category Collection
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {*} [accumulator] The initial value.
      * @returns {*} Returns the accumulated value.
+     * @see _.reduceRight
      * @example
      *
-     * var sum = _.reduce([1, 2, 3], function(sum, num) {
-     *   return sum + num;
-     * });
-     * // => 6
+     * _.reduce([1, 2], function(sum, n) {
+     *   return sum + n;
+     * }, 0);
+     * // => 3
      *
-     * var mapped = _.reduce({ 'a': 1, 'b': 2, 'c': 3 }, function(result, num, key) {
-     *   result[key] = num * 3;
+     * _.reduce({ 'a': 1, 'b': 2, 'c': 1 }, function(result, value, key) {
+     *   (result[value] || (result[value] = [])).push(key);
      *   return result;
      * }, {});
-     * // => { 'a': 3, 'b': 6, 'c': 9 }
+     * // => { '1': ['a', 'c'], '2': ['b'] } (iteration order is not guaranteed)
      */
-    function reduce(collection, callback, accumulator, thisArg) {
-      var noaccum = arguments.length < 3;
-      callback = lodash.createCallback(callback, thisArg, 4);
+    function reduce(collection, iteratee, accumulator) {
+      var func = isArray(collection) ? arrayReduce : baseReduce,
+          initAccum = arguments.length < 3;
 
-      if (isArray(collection)) {
-        var index = -1,
-            length = collection.length;
-
-        if (noaccum) {
-          accumulator = collection[++index];
-        }
-        while (++index < length) {
-          accumulator = callback(accumulator, collection[index], index, collection);
-        }
-      } else {
-        baseEach(collection, function(value, index, collection) {
-          accumulator = noaccum
-            ? (noaccum = false, value)
-            : callback(accumulator, value, index, collection)
-        });
-      }
-      return accumulator;
+      return func(collection, getIteratee(iteratee, 4), accumulator, initAccum, baseEach);
     }
 
     /**
-     * This method is like `_.reduce` except that it iterates over elements
-     * of a `collection` from right to left.
+     * This method is like `_.reduce` except that it iterates over elements of
+     * `collection` from right to left.
      *
      * @static
      * @memberOf _
-     * @alias foldr
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [accumulator] Initial value of the accumulator.
-     * @param {*} [thisArg] The `this` binding of `callback`.
+     * @since 0.1.0
+     * @category Collection
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {*} [accumulator] The initial value.
      * @returns {*} Returns the accumulated value.
+     * @see _.reduce
      * @example
      *
-     * var list = [[0, 1], [2, 3], [4, 5]];
-     * var flat = _.reduceRight(list, function(a, b) { return a.concat(b); }, []);
+     * var array = [[0, 1], [2, 3], [4, 5]];
+     *
+     * _.reduceRight(array, function(flattened, other) {
+     *   return flattened.concat(other);
+     * }, []);
      * // => [4, 5, 2, 3, 0, 1]
      */
-    function reduceRight(collection, callback, accumulator, thisArg) {
-      var noaccum = arguments.length < 3;
-      callback = lodash.createCallback(callback, thisArg, 4);
-      forEachRight(collection, function(value, index, collection) {
-        accumulator = noaccum
-          ? (noaccum = false, value)
-          : callback(accumulator, value, index, collection);
-      });
-      return accumulator;
+    function reduceRight(collection, iteratee, accumulator) {
+      var func = isArray(collection) ? arrayReduceRight : baseReduce,
+          initAccum = arguments.length < 3;
+
+      return func(collection, getIteratee(iteratee, 4), accumulator, initAccum, baseEachRight);
     }
 
     /**
-     * The opposite of `_.filter` this method returns the elements of a
-     * collection that the callback does **not** return truey for.
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * The opposite of `_.filter`; this method returns the elements of `collection`
+     * that `predicate` does **not** return truthy for.
      *
      * @static
      * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a new array of elements that failed the callback check.
+     * @since 0.1.0
+     * @category Collection
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function} [predicate=_.identity] The function invoked per iteration.
+     * @returns {Array} Returns the new filtered array.
+     * @see _.filter
      * @example
      *
-     * var odds = _.reject([1, 2, 3, 4, 5, 6], function(num) { return num % 2 == 0; });
-     * // => [1, 3, 5]
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36, 'blocked': false },
-     *   { 'name': 'fred',   'age': 40, 'blocked': true }
+     * var users = [
+     *   { 'user': 'barney', 'age': 36, 'active': false },
+     *   { 'user': 'fred',   'age': 40, 'active': true }
      * ];
      *
-     * // using "_.pluck" callback shorthand
-     * _.reject(characters, 'blocked');
-     * // => [{ 'name': 'barney', 'age': 36, 'blocked': false }]
+     * _.reject(users, function(o) { return !o.active; });
+     * // => objects for ['fred']
      *
-     * // using "_.where" callback shorthand
-     * _.reject(characters, { 'age': 36 });
-     * // => [{ 'name': 'fred', 'age': 40, 'blocked': true }]
+     * // The `_.matches` iteratee shorthand.
+     * _.reject(users, { 'age': 40, 'active': true });
+     * // => objects for ['barney']
+     *
+     * // The `_.matchesProperty` iteratee shorthand.
+     * _.reject(users, ['active', false]);
+     * // => objects for ['fred']
+     *
+     * // The `_.property` iteratee shorthand.
+     * _.reject(users, 'active');
+     * // => objects for ['barney']
      */
-    function reject(collection, callback, thisArg) {
-      callback = lodash.createCallback(callback, thisArg, 3);
-      return filter(collection, function(value, index, collection) {
-        return !callback(value, index, collection);
-      });
+    function reject(collection, predicate) {
+      var func = isArray(collection) ? arrayFilter : baseFilter;
+      return func(collection, negate(getIteratee(predicate, 3)));
     }
 
     /**
-     * Retrieves a random element or `n` random elements from a collection.
+     * Gets a random element from `collection`.
      *
      * @static
      * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to sample.
-     * @param {number} [n] The number of elements to sample.
-     * @param- {Object} [guard] Allows working with functions like `_.map`
-     *  without using their `index` arguments as `n`.
-     * @returns {Array} Returns the random sample(s) of `collection`.
+     * @since 2.0.0
+     * @category Collection
+     * @param {Array|Object} collection The collection to sample.
+     * @returns {*} Returns the random element.
      * @example
      *
      * _.sample([1, 2, 3, 4]);
      * // => 2
+     */
+    function sample(collection) {
+      var func = isArray(collection) ? arraySample : baseSample;
+      return func(collection);
+    }
+
+    /**
+     * Gets `n` random elements at unique keys from `collection` up to the
+     * size of `collection`.
      *
-     * _.sample([1, 2, 3, 4], 2);
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Collection
+     * @param {Array|Object} collection The collection to sample.
+     * @param {number} [n=1] The number of elements to sample.
+     * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
+     * @returns {Array} Returns the random elements.
+     * @example
+     *
+     * _.sampleSize([1, 2, 3], 2);
      * // => [3, 1]
+     *
+     * _.sampleSize([1, 2, 3], 4);
+     * // => [2, 3, 1]
      */
-    function sample(collection, n, guard) {
-      if (collection && typeof collection.length != 'number') {
-        collection = values(collection);
-      } else if (support.unindexedChars && isString(collection)) {
-        collection = collection.split('');
-      }
-      if (n == null || guard) {
-        return collection ? collection[baseRandom(0, collection.length - 1)] : undefined;
+    function sampleSize(collection, n, guard) {
+      if ((guard ? isIterateeCall(collection, n, guard) : n === undefined)) {
+        n = 1;
+      } else {
+        n = toInteger(n);
       }
-      var result = shuffle(collection);
-      result.length = nativeMin(nativeMax(0, n), result.length);
-      return result;
+      var func = isArray(collection) ? arraySampleSize : baseSampleSize;
+      return func(collection, n);
     }
 
     /**
-     * Creates an array of shuffled values, using a version of the Fisher-Yates
-     * shuffle. See http://en.wikipedia.org/wiki/Fisher-Yates_shuffle.
+     * Creates an array of shuffled values, using a version of the
+     * [Fisher-Yates shuffle](https://en.wikipedia.org/wiki/Fisher-Yates_shuffle).
      *
      * @static
      * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to shuffle.
-     * @returns {Array} Returns a new shuffled collection.
+     * @since 0.1.0
+     * @category Collection
+     * @param {Array|Object} collection The collection to shuffle.
+     * @returns {Array} Returns the new shuffled array.
      * @example
      *
-     * _.shuffle([1, 2, 3, 4, 5, 6]);
-     * // => [4, 1, 6, 3, 5, 2]
+     * _.shuffle([1, 2, 3, 4]);
+     * // => [4, 1, 3, 2]
      */
     function shuffle(collection) {
-      var index = -1,
-          length = collection ? collection.length : 0,
-          result = Array(typeof length == 'number' ? length : 0);
-
-      forEach(collection, function(value) {
-        var rand = baseRandom(0, ++index);
-        result[index] = result[rand];
-        result[rand] = value;
-      });
-      return result;
+      var func = isArray(collection) ? arrayShuffle : baseShuffle;
+      return func(collection);
     }
 
     /**
-     * Gets the size of the `collection` by returning `collection.length` for arrays
-     * and array-like objects or the number of own enumerable properties for objects.
+     * Gets the size of `collection` by returning its length for array-like
+     * values or the number of own enumerable string keyed properties for objects.
      *
      * @static
      * @memberOf _
-     * @category Collections
+     * @since 0.1.0
+     * @category Collection
      * @param {Array|Object|string} collection The collection to inspect.
-     * @returns {number} Returns `collection.length` or number of own enumerable properties.
+     * @returns {number} Returns the collection size.
      * @example
      *
-     * _.size([1, 2]);
-     * // => 2
-     *
-     * _.size({ 'one': 1, 'two': 2, 'three': 3 });
+     * _.size([1, 2, 3]);
      * // => 3
      *
+     * _.size({ 'a': 1, 'b': 2 });
+     * // => 2
+     *
      * _.size('pebbles');
      * // => 7
      */
     function size(collection) {
-      var length = collection ? collection.length : 0;
-      return typeof length == 'number' ? length : keys(collection).length;
+      if (collection == null) {
+        return 0;
+      }
+      if (isArrayLike(collection)) {
+        return isString(collection) ? stringSize(collection) : collection.length;
+      }
+      var tag = getTag(collection);
+      if (tag == mapTag || tag == setTag) {
+        return collection.size;
+      }
+      return baseKeys(collection).length;
     }
 
     /**
-     * Checks if the callback returns a truey value for **any** element of a
-     * collection. The function returns as soon as it finds a passing value and
-     * does not iterate over the entire collection. The callback is bound to
-     * `thisArg` and invoked with three arguments; (value, index|key, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * Checks if `predicate` returns truthy for **any** element of `collection`.
+     * Iteration is stopped once `predicate` returns truthy. The predicate is
+     * invoked with three arguments: (value, index|key, collection).
      *
      * @static
      * @memberOf _
-     * @alias any
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {boolean} Returns `true` if any element passed the callback check,
+     * @since 0.1.0
+     * @category Collection
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {Function} [predicate=_.identity] The function invoked per iteration.
+     * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
+     * @returns {boolean} Returns `true` if any element passes the predicate check,
      *  else `false`.
      * @example
      *
      * _.some([null, 0, 'yes', false], Boolean);
      * // => true
      *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36, 'blocked': false },
-     *   { 'name': 'fred',   'age': 40, 'blocked': true }
+     * var users = [
+     *   { 'user': 'barney', 'active': true },
+     *   { 'user': 'fred',   'active': false }
      * ];
      *
-     * // using "_.pluck" callback shorthand
-     * _.some(characters, 'blocked');
+     * // The `_.matches` iteratee shorthand.
+     * _.some(users, { 'user': 'barney', 'active': false });
+     * // => false
+     *
+     * // The `_.matchesProperty` iteratee shorthand.
+     * _.some(users, ['active', false]);
      * // => true
      *
-     * // using "_.where" callback shorthand
-     * _.some(characters, { 'age': 1 });
-     * // => false
+     * // The `_.property` iteratee shorthand.
+     * _.some(users, 'active');
+     * // => true
      */
-    function some(collection, callback, thisArg) {
-      var result;
-      callback = lodash.createCallback(callback, thisArg, 3);
-
-      if (isArray(collection)) {
-        var index = -1,
-            length = collection.length;
-
-        while (++index < length) {
-          if ((result = callback(collection[index], index, collection))) {
-            break;
-          }
-        }
-      } else {
-        baseEach(collection, function(value, index, collection) {
-          return !(result = callback(value, index, collection));
-        });
+    function some(collection, predicate, guard) {
+      var func = isArray(collection) ? arraySome : baseSome;
+      if (guard && isIterateeCall(collection, predicate, guard)) {
+        predicate = undefined;
       }
-      return !!result;
+      return func(collection, getIteratee(predicate, 3));
     }
 
     /**
      * Creates an array of elements, sorted in ascending order by the results of
-     * running each element in a collection through the callback. This method
-     * performs a stable sort, that is, it will preserve the original sort order
-     * of equal elements. The callback is bound to `thisArg` and invoked with
-     * three arguments; (value, index|key, collection).
+     * running each element in a collection thru each iteratee. This method
+     * performs a stable sort, that is, it preserves the original sort order of
+     * equal elements. The iteratees are invoked with one argument: (value).
      *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
+     * @static
+     * @memberOf _
+     * @since 0.1.0
+     * @category Collection
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {...(Function|Function[])} [iteratees=[_.identity]]
+     *  The iteratees to sort by.
+     * @returns {Array} Returns the new sorted array.
+     * @example
      *
-     * If an array of property names is provided for `callback` the collection
-     * will be sorted by each property value.
+     * var users = [
+     *   { 'user': 'fred',   'age': 48 },
+     *   { 'user': 'barney', 'age': 36 },
+     *   { 'user': 'fred',   'age': 30 },
+     *   { 'user': 'barney', 'age': 34 }
+     * ];
+     *
+     * _.sortBy(users, [function(o) { return o.user; }]);
+     * // => objects for [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 30]]
      *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * _.sortBy(users, ['user', 'age']);
+     * // => objects for [['barney', 34], ['barney', 36], ['fred', 30], ['fred', 48]]
+     */
+    var sortBy = baseRest(function(collection, iteratees) {
+      if (collection == null) {
+        return [];
+      }
+      var length = iteratees.length;
+      if (length > 1 && isIterateeCall(collection, iteratees[0], iteratees[1])) {
+        iteratees = [];
+      } else if (length > 2 && isIterateeCall(iteratees[0], iteratees[1], iteratees[2])) {
+        iteratees = [iteratees[0]];
+      }
+      return baseOrderBy(collection, baseFlatten(iteratees, 1), []);
+    });
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Gets the timestamp of the number of milliseconds that have elapsed since
+     * the Unix epoch (1 January 1970 00:00:00 UTC).
      *
      * @static
      * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Array|Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a new array of sorted elements.
+     * @since 2.4.0
+     * @category Date
+     * @returns {number} Returns the timestamp.
      * @example
      *
-     * _.sortBy([1, 2, 3], function(num) { return Math.sin(num); });
-     * // => [3, 1, 2]
+     * _.defer(function(stamp) {
+     *   console.log(_.now() - stamp);
+     * }, _.now());
+     * // => Logs the number of milliseconds it took for the deferred invocation.
+     */
+    var now = ctxNow || function() {
+      return root.Date.now();
+    };
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * The opposite of `_.before`; this method creates a function that invokes
+     * `func` once it's called `n` or more times.
      *
-     * _.sortBy([1, 2, 3], function(num) { return this.sin(num); }, Math);
-     * // => [3, 1, 2]
+     * @static
+     * @memberOf _
+     * @since 0.1.0
+     * @category Function
+     * @param {number} n The number of calls before `func` is invoked.
+     * @param {Function} func The function to restrict.
+     * @returns {Function} Returns the new restricted function.
+     * @example
      *
-     * var characters = [
-     *   { 'name': 'barney',  'age': 36 },
-     *   { 'name': 'fred',    'age': 40 },
-     *   { 'name': 'barney',  'age': 26 },
-     *   { 'name': 'fred',    'age': 30 }
-     * ];
+     * var saves = ['profile', 'settings'];
      *
-     * // using "_.pluck" callback shorthand
-     * _.map(_.sortBy(characters, 'age'), _.values);
-     * // => [['barney', 26], ['fred', 30], ['barney', 36], ['fred', 40]]
-     *
-     * // sorting by multiple properties
-     * _.map(_.sortBy(characters, ['name', 'age']), _.values);
-     * // = > [['barney', 26], ['barney', 36], ['fred', 30], ['fred', 40]]
+     * var done = _.after(saves.length, function() {
+     *   console.log('done saving!');
+     * });
+     *
+     * _.forEach(saves, function(type) {
+     *   asyncSave({ 'type': type, 'complete': done });
+     * });
+     * // => Logs 'done saving!' after the two async saves have completed.
      */
-    function sortBy(collection, callback, thisArg) {
-      var index = -1,
-          isArr = isArray(callback),
-          length = collection ? collection.length : 0,
-          result = Array(typeof length == 'number' ? length : 0);
-
-      if (!isArr) {
-        callback = lodash.createCallback(callback, thisArg, 3);
-      }
-      forEach(collection, function(value, key, collection) {
-        var object = result[++index] = getObject();
-        if (isArr) {
-          object.criteria = map(callback, function(key) { return value[key]; });
-        } else {
-          (object.criteria = getArray())[0] = callback(value, key, collection);
+    function after(n, func) {
+      if (typeof func != 'function') {
+        throw new TypeError(FUNC_ERROR_TEXT);
+      }
+      n = toInteger(n);
+      return function() {
+        if (--n < 1) {
+          return func.apply(this, arguments);
         }
-        object.index = index;
-        object.value = value;
-      });
+      };
+    }
 
-      length = result.length;
-      result.sort(compareAscending);
-      while (length--) {
-        var object = result[length];
-        result[length] = object.value;
-        if (!isArr) {
-          releaseArray(object.criteria);
-        }
-        releaseObject(object);
-      }
-      return result;
+    /**
+     * Creates a function that invokes `func`, with up to `n` arguments,
+     * ignoring any additional arguments.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category Function
+     * @param {Function} func The function to cap arguments for.
+     * @param {number} [n=func.length] The arity cap.
+     * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
+     * @returns {Function} Returns the new capped function.
+     * @example
+     *
+     * _.map(['6', '8', '10'], _.ary(parseInt, 1));
+     * // => [6, 8, 10]
+     */
+    function ary(func, n, guard) {
+      n = guard ? undefined : n;
+      n = (func && n == null) ? func.length : n;
+      return createWrap(func, WRAP_ARY_FLAG, undefined, undefined, undefined, undefined, n);
     }
 
     /**
-     * Converts the `collection` to an array.
+     * Creates a function that invokes `func`, with the `this` binding and arguments
+     * of the created function, while it's called less than `n` times. Subsequent
+     * calls to the created function return the result of the last `func` invocation.
      *
      * @static
      * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to convert.
-     * @returns {Array} Returns the new converted array.
+     * @since 3.0.0
+     * @category Function
+     * @param {number} n The number of calls at which `func` is no longer invoked.
+     * @param {Function} func The function to restrict.
+     * @returns {Function} Returns the new restricted function.
      * @example
      *
-     * (function() { return _.toArray(arguments).slice(1); })(1, 2, 3, 4);
-     * // => [2, 3, 4]
+     * jQuery(element).on('click', _.before(5, addContactToList));
+     * // => Allows adding up to 4 contacts to the list.
      */
-    function toArray(collection) {
-      if (collection && typeof collection.length == 'number') {
-        return (support.unindexedChars && isString(collection))
-          ? collection.split('')
-          : slice(collection);
+    function before(n, func) {
+      var result;
+      if (typeof func != 'function') {
+        throw new TypeError(FUNC_ERROR_TEXT);
       }
-      return values(collection);
+      n = toInteger(n);
+      return function() {
+        if (--n > 0) {
+          result = func.apply(this, arguments);
+        }
+        if (n <= 1) {
+          func = undefined;
+        }
+        return result;
+      };
     }
 
     /**
-     * Performs a deep comparison of each element in a `collection` to the given
-     * `properties` object, returning an array of all elements that have equivalent
-     * property values.
+     * Creates a function that invokes `func` with the `this` binding of `thisArg`
+     * and `partials` prepended to the arguments it receives.
+     *
+     * The `_.bind.placeholder` value, which defaults to `_` in monolithic builds,
+     * may be used as a placeholder for partially applied arguments.
+     *
+     * **Note:** Unlike native `Function#bind`, this method doesn't set the "length"
+     * property of bound functions.
      *
      * @static
      * @memberOf _
-     * @type Function
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Object} props The object of property values to filter by.
-     * @returns {Array} Returns a new array of elements that have the given properties.
+     * @since 0.1.0
+     * @category Function
+     * @param {Function} func The function to bind.
+     * @param {*} thisArg The `this` binding of `func`.
+     * @param {...*} [partials] The arguments to be partially applied.
+     * @returns {Function} Returns the new bound function.
      * @example
      *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36, 'pets': ['hoppy'] },
-     *   { 'name': 'fred',   'age': 40, 'pets': ['baby puss', 'dino'] }
-     * ];
+     * function greet(greeting, punctuation) {
+     *   return greeting + ' ' + this.user + punctuation;
+     * }
      *
-     * _.where(characters, { 'age': 36 });
-     * // => [{ 'name': 'barney', 'age': 36, 'pets': ['hoppy'] }]
+     * var object = { 'user': 'fred' };
      *
-     * _.where(characters, { 'pets': ['dino'] });
-     * // => [{ 'name': 'fred', 'age': 40, 'pets': ['baby puss', 'dino'] }]
-     */
-    var where = filter;
+     * var bound = _.bind(greet, object, 'hi');
+     * bound('!');
+     * // => 'hi fred!'
+     *
+     * // Bound with placeholders.
+     * var bound = _.bind(greet, object, _, '!');
+     * bound('hi');
+     * // => 'hi fred!'
+     */
+    var bind = baseRest(function(func, thisArg, partials) {
+      var bitmask = WRAP_BIND_FLAG;
+      if (partials.length) {
+        var holders = replaceHolders(partials, getHolder(bind));
+        bitmask |= WRAP_PARTIAL_FLAG;
+      }
+      return createWrap(func, bitmask, thisArg, partials, holders);
+    });
 
-    /*--------------------------------------------------------------------------*/
+    /**
+     * Creates a function that invokes the method at `object[key]` with `partials`
+     * prepended to the arguments it receives.
+     *
+     * This method differs from `_.bind` by allowing bound functions to reference
+     * methods that may be redefined or don't yet exist. See
+     * [Peter Michaux's article](http://peter.michaux.ca/articles/lazy-function-definition-pattern)
+     * for more details.
+     *
+     * The `_.bindKey.placeholder` value, which defaults to `_` in monolithic
+     * builds, may be used as a placeholder for partially applied arguments.
+     *
+     * @static
+     * @memberOf _
+     * @since 0.10.0
+     * @category Function
+     * @param {Object} object The object to invoke the method on.
+     * @param {string} key The key of the method.
+     * @param {...*} [partials] The arguments to be partially applied.
+     * @returns {Function} Returns the new bound function.
+     * @example
+     *
+     * var object = {
+     *   'user': 'fred',
+     *   'greet': function(greeting, punctuation) {
+     *     return greeting + ' ' + this.user + punctuation;
+     *   }
+     * };
+     *
+     * var bound = _.bindKey(object, 'greet', 'hi');
+     * bound('!');
+     * // => 'hi fred!'
+     *
+     * object.greet = function(greeting, punctuation) {
+     *   return greeting + 'ya ' + this.user + punctuation;
+     * };
+     *
+     * bound('!');
+     * // => 'hiya fred!'
+     *
+     * // Bound with placeholders.
+     * var bound = _.bindKey(object, 'greet', _, '!');
+     * bound('hi');
+     * // => 'hiya fred!'
+     */
+    var bindKey = baseRest(function(object, key, partials) {
+      var bitmask = WRAP_BIND_FLAG | WRAP_BIND_KEY_FLAG;
+      if (partials.length) {
+        var holders = replaceHolders(partials, getHolder(bindKey));
+        bitmask |= WRAP_PARTIAL_FLAG;
+      }
+      return createWrap(key, bitmask, object, partials, holders);
+    });
 
     /**
-     * Creates an array with all falsey values removed. The values `false`, `null`,
-     * `0`, `""`, `undefined`, and `NaN` are all falsey.
+     * Creates a function that accepts arguments of `func` and either invokes
+     * `func` returning its result, if at least `arity` number of arguments have
+     * been provided, or returns a function that accepts the remaining `func`
+     * arguments, and so on. The arity of `func` may be specified if `func.length`
+     * is not sufficient.
+     *
+     * The `_.curry.placeholder` value, which defaults to `_` in monolithic builds,
+     * may be used as a placeholder for provided arguments.
+     *
+     * **Note:** This method doesn't set the "length" property of curried functions.
      *
      * @static
      * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to compact.
-     * @returns {Array} Returns a new array of filtered values.
+     * @since 2.0.0
+     * @category Function
+     * @param {Function} func The function to curry.
+     * @param {number} [arity=func.length] The arity of `func`.
+     * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
+     * @returns {Function} Returns the new curried function.
      * @example
      *
-     * _.compact([0, 1, false, 2, '', 3]);
+     * var abc = function(a, b, c) {
+     *   return [a, b, c];
+     * };
+     *
+     * var curried = _.curry(abc);
+     *
+     * curried(1)(2)(3);
+     * // => [1, 2, 3]
+     *
+     * curried(1, 2)(3);
+     * // => [1, 2, 3]
+     *
+     * curried(1, 2, 3);
+     * // => [1, 2, 3]
+     *
+     * // Curried with placeholders.
+     * curried(1)(_, 3)(2);
      * // => [1, 2, 3]
      */
-    function compact(array) {
-      var index = -1,
-          length = array ? array.length : 0,
-          result = [];
-
-      while (++index < length) {
-        var value = array[index];
-        if (value) {
-          result.push(value);
-        }
-      }
+    function curry(func, arity, guard) {
+      arity = guard ? undefined : arity;
+      var result = createWrap(func, WRAP_CURRY_FLAG, undefined, undefined, undefined, undefined, undefined, arity);
+      result.placeholder = curry.placeholder;
       return result;
     }
 
     /**
-     * Creates an array excluding all values of the provided arrays using strict
-     * equality for comparisons, i.e. `===`.
+     * This method is like `_.curry` except that arguments are applied to `func`
+     * in the manner of `_.partialRight` instead of `_.partial`.
+     *
+     * The `_.curryRight.placeholder` value, which defaults to `_` in monolithic
+     * builds, may be used as a placeholder for provided arguments.
+     *
+     * **Note:** This method doesn't set the "length" property of curried functions.
      *
      * @static
      * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to process.
-     * @param {...Array} [values] The arrays of values to exclude.
-     * @returns {Array} Returns a new array of filtered values.
+     * @since 3.0.0
+     * @category Function
+     * @param {Function} func The function to curry.
+     * @param {number} [arity=func.length] The arity of `func`.
+     * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
+     * @returns {Function} Returns the new curried function.
      * @example
      *
-     * _.difference([1, 2, 3, 4, 5], [5, 2, 10]);
-     * // => [1, 3, 4]
+     * var abc = function(a, b, c) {
+     *   return [a, b, c];
+     * };
+     *
+     * var curried = _.curryRight(abc);
+     *
+     * curried(3)(2)(1);
+     * // => [1, 2, 3]
+     *
+     * curried(2, 3)(1);
+     * // => [1, 2, 3]
+     *
+     * curried(1, 2, 3);
+     * // => [1, 2, 3]
+     *
+     * // Curried with placeholders.
+     * curried(3)(1, _)(2);
+     * // => [1, 2, 3]
      */
-    function difference(array) {
-      return baseDifference(array, baseFlatten(arguments, true, true, 1));
+    function curryRight(func, arity, guard) {
+      arity = guard ? undefined : arity;
+      var result = createWrap(func, WRAP_CURRY_RIGHT_FLAG, undefined, undefined, undefined, undefined, undefined, arity);
+      result.placeholder = curryRight.placeholder;
+      return result;
     }
 
     /**
-     * This method is like `_.find` except that it returns the index of the first
-     * element that passes the callback check, instead of the element itself.
+     * Creates a debounced function that delays invoking `func` until after `wait`
+     * milliseconds have elapsed since the last time the debounced function was
+     * invoked. The debounced function comes with a `cancel` method to cancel
+     * delayed `func` invocations and a `flush` method to immediately invoke them.
+     * Provide `options` to indicate whether `func` should be invoked on the
+     * leading and/or trailing edge of the `wait` timeout. The `func` is invoked
+     * with the last arguments provided to the debounced function. Subsequent
+     * calls to the debounced function return the result of the last `func`
+     * invocation.
+     *
+     * **Note:** If `leading` and `trailing` options are `true`, `func` is
+     * invoked on the trailing edge of the timeout only if the debounced function
+     * is invoked more than once during the `wait` timeout.
+     *
+     * If `wait` is `0` and `leading` is `false`, `func` invocation is deferred
+     * until to the next tick, similar to `setTimeout` with a timeout of `0`.
      *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * See [David Corbacho's article](https://css-tricks.com/debouncing-throttling-explained-examples/)
+     * for details over the differences between `_.debounce` and `_.throttle`.
      *
      * @static
      * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to search.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {number} Returns the index of the found element, else `-1`.
+     * @since 0.1.0
+     * @category Function
+     * @param {Function} func The function to debounce.
+     * @param {number} [wait=0] The number of milliseconds to delay.
+     * @param {Object} [options={}] The options object.
+     * @param {boolean} [options.leading=false]
+     *  Specify invoking on the leading edge of the timeout.
+     * @param {number} [options.maxWait]
+     *  The maximum time `func` is allowed to be delayed before it's invoked.
+     * @param {boolean} [options.trailing=true]
+     *  Specify invoking on the trailing edge of the timeout.
+     * @returns {Function} Returns the new debounced function.
      * @example
      *
-     * var characters = [
-     *   { 'name': 'barney',  'age': 36, 'blocked': false },
-     *   { 'name': 'fred',    'age': 40, 'blocked': true },
-     *   { 'name': 'pebbles', 'age': 1,  'blocked': false }
-     * ];
+     * // Avoid costly calculations while the window size is in flux.
+     * jQuery(window).on('resize', _.debounce(calculateLayout, 150));
      *
-     * _.findIndex(characters, function(chr) {
-     *   return chr.age < 20;
-     * });
-     * // => 2
+     * // Invoke `sendMail` when clicked, debouncing subsequent calls.
+     * jQuery(element).on('click', _.debounce(sendMail, 300, {
+     *   'leading': true,
+     *   'trailing': false
+     * }));
      *
-     * // using "_.where" callback shorthand
-     * _.findIndex(characters, { 'age': 36 });
-     * // => 0
+     * // Ensure `batchLog` is invoked once after 1 second of debounced calls.
+     * var debounced = _.debounce(batchLog, 250, { 'maxWait': 1000 });
+     * var source = new EventSource('/stream');
+     * jQuery(source).on('message', debounced);
      *
-     * // using "_.pluck" callback shorthand
-     * _.findIndex(characters, 'blocked');
-     * // => 1
+     * // Cancel the trailing debounced invocation.
+     * jQuery(window).on('popstate', debounced.cancel);
      */
-    function findIndex(array, callback, thisArg) {
-      var index = -1,
-          length = array ? array.length : 0;
+    function debounce(func, wait, options) {
+      var lastArgs,
+          lastThis,
+          maxWait,
+          result,
+          timerId,
+          lastCallTime,
+          lastInvokeTime = 0,
+          leading = false,
+          maxing = false,
+          trailing = true;
 
-      callback = lodash.createCallback(callback, thisArg, 3);
-      while (++index < length) {
-        if (callback(array[index], index, array)) {
-          return index;
+      if (typeof func != 'function') {
+        throw new TypeError(FUNC_ERROR_TEXT);
+      }
+      wait = toNumber(wait) || 0;
+      if (isObject(options)) {
+        leading = !!options.leading;
+        maxing = 'maxWait' in options;
+        maxWait = maxing ? nativeMax(toNumber(options.maxWait) || 0, wait) : maxWait;
+        trailing = 'trailing' in options ? !!options.trailing : trailing;
+      }
+
+      function invokeFunc(time) {
+        var args = lastArgs,
+            thisArg = lastThis;
+
+        lastArgs = lastThis = undefined;
+        lastInvokeTime = time;
+        result = func.apply(thisArg, args);
+        return result;
+      }
+
+      function leadingEdge(time) {
+        // Reset any `maxWait` timer.
+        lastInvokeTime = time;
+        // Start the timer for the trailing edge.
+        timerId = setTimeout(timerExpired, wait);
+        // Invoke the leading edge.
+        return leading ? invokeFunc(time) : result;
+      }
+
+      function remainingWait(time) {
+        var timeSinceLastCall = time - lastCallTime,
+            timeSinceLastInvoke = time - lastInvokeTime,
+            timeWaiting = wait - timeSinceLastCall;
+
+        return maxing
+          ? nativeMin(timeWaiting, maxWait - timeSinceLastInvoke)
+          : timeWaiting;
+      }
+
+      function shouldInvoke(time) {
+        var timeSinceLastCall = time - lastCallTime,
+            timeSinceLastInvoke = time - lastInvokeTime;
+
+        // Either this is the first call, activity has stopped and we're at the
+        // trailing edge, the system time has gone backwards and we're treating
+        // it as the trailing edge, or we've hit the `maxWait` limit.
+        return (lastCallTime === undefined || (timeSinceLastCall >= wait) ||
+          (timeSinceLastCall < 0) || (maxing && timeSinceLastInvoke >= maxWait));
+      }
+
+      function timerExpired() {
+        var time = now();
+        if (shouldInvoke(time)) {
+          return trailingEdge(time);
         }
+        // Restart the timer.
+        timerId = setTimeout(timerExpired, remainingWait(time));
       }
-      return -1;
+
+      function trailingEdge(time) {
+        timerId = undefined;
+
+        // Only invoke if we have `lastArgs` which means `func` has been
+        // debounced at least once.
+        if (trailing && lastArgs) {
+          return invokeFunc(time);
+        }
+        lastArgs = lastThis = undefined;
+        return result;
+      }
+
+      function cancel() {
+        if (timerId !== undefined) {
+          clearTimeout(timerId);
+        }
+        lastInvokeTime = 0;
+        lastArgs = lastCallTime = lastThis = timerId = undefined;
+      }
+
+      function flush() {
+        return timerId === undefined ? result : trailingEdge(now());
+      }
+
+      function debounced() {
+        var time = now(),
+            isInvoking = shouldInvoke(time);
+
+        lastArgs = arguments;
+        lastThis = this;
+        lastCallTime = time;
+
+        if (isInvoking) {
+          if (timerId === undefined) {
+            return leadingEdge(lastCallTime);
+          }
+          if (maxing) {
+            // Handle invocations in a tight loop.
+            clearTimeout(timerId);
+            timerId = setTimeout(timerExpired, wait);
+            return invokeFunc(lastCallTime);
+          }
+        }
+        if (timerId === undefined) {
+          timerId = setTimeout(timerExpired, wait);
+        }
+        return result;
+      }
+      debounced.cancel = cancel;
+      debounced.flush = flush;
+      return debounced;
     }
 
     /**
-     * This method is like `_.findIndex` except that it iterates over elements
-     * of a `collection` from right to left.
+     * Defers invoking the `func` until the current call stack has cleared. Any
+     * additional arguments are provided to `func` when it's invoked.
      *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
+     * @static
+     * @memberOf _
+     * @since 0.1.0
+     * @category Function
+     * @param {Function} func The function to defer.
+     * @param {...*} [args] The arguments to invoke `func` with.
+     * @returns {number} Returns the timer id.
+     * @example
      *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * _.defer(function(text) {
+     *   console.log(text);
+     * }, 'deferred');
+     * // => Logs 'deferred' after one millisecond.
+     */
+    var defer = baseRest(function(func, args) {
+      return baseDelay(func, 1, args);
+    });
+
+    /**
+     * Invokes `func` after `wait` milliseconds. Any additional arguments are
+     * provided to `func` when it's invoked.
      *
      * @static
      * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to search.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {number} Returns the index of the found element, else `-1`.
+     * @since 0.1.0
+     * @category Function
+     * @param {Function} func The function to delay.
+     * @param {number} wait The number of milliseconds to delay invocation.
+     * @param {...*} [args] The arguments to invoke `func` with.
+     * @returns {number} Returns the timer id.
      * @example
      *
-     * var characters = [
-     *   { 'name': 'barney',  'age': 36, 'blocked': true },
-     *   { 'name': 'fred',    'age': 40, 'blocked': false },
-     *   { 'name': 'pebbles', 'age': 1,  'blocked': true }
-     * ];
+     * _.delay(function(text) {
+     *   console.log(text);
+     * }, 1000, 'later');
+     * // => Logs 'later' after one second.
+     */
+    var delay = baseRest(function(func, wait, args) {
+      return baseDelay(func, toNumber(wait) || 0, args);
+    });
+
+    /**
+     * Creates a function that invokes `func` with arguments reversed.
      *
-     * _.findLastIndex(characters, function(chr) {
-     *   return chr.age > 30;
-     * });
-     * // => 1
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Function
+     * @param {Function} func The function to flip arguments for.
+     * @returns {Function} Returns the new flipped function.
+     * @example
      *
-     * // using "_.where" callback shorthand
-     * _.findLastIndex(characters, { 'age': 36 });
-     * // => 0
+     * var flipped = _.flip(function() {
+     *   return _.toArray(arguments);
+     * });
      *
-     * // using "_.pluck" callback shorthand
-     * _.findLastIndex(characters, 'blocked');
-     * // => 2
+     * flipped('a', 'b', 'c', 'd');
+     * // => ['d', 'c', 'b', 'a']
      */
-    function findLastIndex(array, callback, thisArg) {
-      var length = array ? array.length : 0;
-      callback = lodash.createCallback(callback, thisArg, 3);
-      while (length--) {
-        if (callback(array[length], length, array)) {
-          return length;
-        }
-      }
-      return -1;
+    function flip(func) {
+      return createWrap(func, WRAP_FLIP_FLAG);
     }
 
     /**
-     * Gets the first element or first `n` elements of an array. If a callback
-     * is provided elements at the beginning of the array are returned as long
-     * as the callback returns truey. The callback is bound to `thisArg` and
-     * invoked with three arguments; (value, index, array).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
+     * Creates a function that memoizes the result of `func`. If `resolver` is
+     * provided, it determines the cache key for storing the result based on the
+     * arguments provided to the memoized function. By default, the first argument
+     * provided to the memoized function is used as the map cache key. The `func`
+     * is invoked with the `this` binding of the memoized function.
      *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * **Note:** The cache is exposed as the `cache` property on the memoized
+     * function. Its creation may be customized by replacing the `_.memoize.Cache`
+     * constructor with one whose instances implement the
+     * [`Map`](http://ecma-international.org/ecma-262/7.0/#sec-properties-of-the-map-prototype-object)
+     * method interface of `clear`, `delete`, `get`, `has`, and `set`.
      *
      * @static
      * @memberOf _
-     * @alias head, take
-     * @category Arrays
-     * @param {Array} array The array to query.
-     * @param {Function|Object|number|string} [callback] The function called
-     *  per element or the number of elements to return. If a property name or
-     *  object is provided it will be used to create a "_.pluck" or "_.where"
-     *  style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the first element(s) of `array`.
+     * @since 0.1.0
+     * @category Function
+     * @param {Function} func The function to have its output memoized.
+     * @param {Function} [resolver] The function to resolve the cache key.
+     * @returns {Function} Returns the new memoized function.
      * @example
      *
-     * _.first([1, 2, 3]);
-     * // => 1
+     * var object = { 'a': 1, 'b': 2 };
+     * var other = { 'c': 3, 'd': 4 };
      *
-     * _.first([1, 2, 3], 2);
+     * var values = _.memoize(_.values);
+     * values(object);
      * // => [1, 2]
      *
-     * _.first([1, 2, 3], function(num) {
-     *   return num < 3;
-     * });
-     * // => [1, 2]
+     * values(other);
+     * // => [3, 4]
      *
-     * var characters = [
-     *   { 'name': 'barney',  'blocked': true,  'employer': 'slate' },
-     *   { 'name': 'fred',    'blocked': false, 'employer': 'slate' },
-     *   { 'name': 'pebbles', 'blocked': true,  'employer': 'na' }
-     * ];
+     * object.a = 2;
+     * values(object);
+     * // => [1, 2]
      *
-     * // using "_.pluck" callback shorthand
-     * _.first(characters, 'blocked');
-     * // => [{ 'name': 'barney', 'blocked': true, 'employer': 'slate' }]
+     * // Modify the result cache.
+     * values.cache.set(object, ['a', 'b']);
+     * values(object);
+     * // => ['a', 'b']
      *
-     * // using "_.where" callback shorthand
-     * _.pluck(_.first(characters, { 'employer': 'slate' }), 'name');
-     * // => ['barney', 'fred']
+     * // Replace `_.memoize.Cache`.
+     * _.memoize.Cache = WeakMap;
      */
-    function first(array, callback, thisArg) {
-      var n = 0,
-          length = array ? array.length : 0;
+    function memoize(func, resolver) {
+      if (typeof func != 'function' || (resolver != null && typeof resolver != 'function')) {
+        throw new TypeError(FUNC_ERROR_TEXT);
+      }
+      var memoized = function() {
+        var args = arguments,
+            key = resolver ? resolver.apply(this, args) : args[0],
+            cache = memoized.cache;
 
-      if (typeof callback != 'number' && callback != null) {
-        var index = -1;
-        callback = lodash.createCallback(callback, thisArg, 3);
-        while (++index < length && callback(array[index], index, array)) {
-          n++;
-        }
-      } else {
-        n = callback;
-        if (n == null || thisArg) {
-          return array ? array[0] : undefined;
+        if (cache.has(key)) {
+          return cache.get(key);
         }
+        var result = func.apply(this, args);
+        memoized.cache = cache.set(key, result) || cache;
+        return result;
+      };
+      memoized.cache = new (memoize.Cache || MapCache);
+      return memoized;
+    }
+
+    // Expose `MapCache`.
+    memoize.Cache = MapCache;
+
+    /**
+     * Creates a function that negates the result of the predicate `func`. The
+     * `func` predicate is invoked with the `this` binding and arguments of the
+     * created function.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category Function
+     * @param {Function} predicate The predicate to negate.
+     * @returns {Function} Returns the new negated function.
+     * @example
+     *
+     * function isEven(n) {
+     *   return n % 2 == 0;
+     * }
+     *
+     * _.filter([1, 2, 3, 4, 5, 6], _.negate(isEven));
+     * // => [1, 3, 5]
+     */
+    function negate(predicate) {
+      if (typeof predicate != 'function') {
+        throw new TypeError(FUNC_ERROR_TEXT);
       }
-      return slice(array, 0, nativeMin(nativeMax(0, n), length));
+      return function() {
+        var args = arguments;
+        switch (args.length) {
+          case 0: return !predicate.call(this);
+          case 1: return !predicate.call(this, args[0]);
+          case 2: return !predicate.call(this, args[0], args[1]);
+          case 3: return !predicate.call(this, args[0], args[1], args[2]);
+        }
+        return !predicate.apply(this, args);
+      };
     }
 
     /**
-     * Flattens a nested array (the nesting can be to any depth). If `isShallow`
-     * is truey, the array will only be flattened a single level. If a callback
-     * is provided each element of the array is passed through the callback before
-     * flattening. The callback is bound to `thisArg` and invoked with three
-     * arguments; (value, index, array).
+     * Creates a function that is restricted to invoking `func` once. Repeat calls
+     * to the function return the value of the first invocation. The `func` is
+     * invoked with the `this` binding and arguments of the created function.
      *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
+     * @static
+     * @memberOf _
+     * @since 0.1.0
+     * @category Function
+     * @param {Function} func The function to restrict.
+     * @returns {Function} Returns the new restricted function.
+     * @example
      *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * var initialize = _.once(createApplication);
+     * initialize();
+     * initialize();
+     * // => `createApplication` is invoked once
+     */
+    function once(func) {
+      return before(2, func);
+    }
+
+    /**
+     * Creates a function that invokes `func` with its arguments transformed.
      *
      * @static
+     * @since 4.0.0
      * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to flatten.
-     * @param {boolean} [isShallow=false] A flag to restrict flattening to a single level.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a new flattened array.
-     * @example
-     *
-     * _.flatten([1, [2], [3, [[4]]]]);
-     * // => [1, 2, 3, 4];
-     *
-     * _.flatten([1, [2], [3, [[4]]]], true);
-     * // => [1, 2, 3, [[4]]];
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 30, 'pets': ['hoppy'] },
-     *   { 'name': 'fred',   'age': 40, 'pets': ['baby puss', 'dino'] }
-     * ];
+     * @category Function
+     * @param {Function} func The function to wrap.
+     * @param {...(Function|Function[])} [transforms=[_.identity]]
+     *  The argument transforms.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * function doubled(n) {
+     *   return n * 2;
+     * }
+     *
+     * function square(n) {
+     *   return n * n;
+     * }
+     *
+     * var func = _.overArgs(function(x, y) {
+     *   return [x, y];
+     * }, [square, doubled]);
+     *
+     * func(9, 3);
+     * // => [81, 6]
+     *
+     * func(10, 5);
+     * // => [100, 10]
+     */
+    var overArgs = castRest(function(func, transforms) {
+      transforms = (transforms.length == 1 && isArray(transforms[0]))
+        ? arrayMap(transforms[0], baseUnary(getIteratee()))
+        : arrayMap(baseFlatten(transforms, 1), baseUnary(getIteratee()));
+
+      var funcsLength = transforms.length;
+      return baseRest(function(args) {
+        var index = -1,
+            length = nativeMin(args.length, funcsLength);
+
+        while (++index < length) {
+          args[index] = transforms[index].call(this, args[index]);
+        }
+        return apply(func, this, args);
+      });
+    });
+
+    /**
+     * Creates a function that invokes `func` with `partials` prepended to the
+     * arguments it receives. This method is like `_.bind` except it does **not**
+     * alter the `this` binding.
+     *
+     * The `_.partial.placeholder` value, which defaults to `_` in monolithic
+     * builds, may be used as a placeholder for partially applied arguments.
+     *
+     * **Note:** This method doesn't set the "length" property of partially
+     * applied functions.
+     *
+     * @static
+     * @memberOf _
+     * @since 0.2.0
+     * @category Function
+     * @param {Function} func The function to partially apply arguments to.
+     * @param {...*} [partials] The arguments to be partially applied.
+     * @returns {Function} Returns the new partially applied function.
+     * @example
+     *
+     * function greet(greeting, name) {
+     *   return greeting + ' ' + name;
+     * }
      *
-     * // using "_.pluck" callback shorthand
-     * _.flatten(characters, 'pets');
-     * // => ['hoppy', 'baby puss', 'dino']
+     * var sayHelloTo = _.partial(greet, 'hello');
+     * sayHelloTo('fred');
+     * // => 'hello fred'
+     *
+     * // Partially applied with placeholders.
+     * var greetFred = _.partial(greet, _, 'fred');
+     * greetFred('hi');
+     * // => 'hi fred'
      */
-    function flatten(array, isShallow, callback, thisArg) {
-      // juggle arguments
-      if (typeof isShallow != 'boolean' && isShallow != null) {
-        thisArg = callback;
-        callback = (typeof isShallow != 'function' && thisArg && thisArg[isShallow] === array) ? null : isShallow;
-        isShallow = false;
-      }
-      if (callback != null) {
-        array = map(array, callback, thisArg);
+    var partial = baseRest(function(func, partials) {
+      var holders = replaceHolders(partials, getHolder(partial));
+      return createWrap(func, WRAP_PARTIAL_FLAG, undefined, partials, holders);
+    });
+
+    /**
+     * This method is like `_.partial` except that partially applied arguments
+     * are appended to the arguments it receives.
+     *
+     * The `_.partialRight.placeholder` value, which defaults to `_` in monolithic
+     * builds, may be used as a placeholder for partially applied arguments.
+     *
+     * **Note:** This method doesn't set the "length" property of partially
+     * applied functions.
+     *
+     * @static
+     * @memberOf _
+     * @since 1.0.0
+     * @category Function
+     * @param {Function} func The function to partially apply arguments to.
+     * @param {...*} [partials] The arguments to be partially applied.
+     * @returns {Function} Returns the new partially applied function.
+     * @example
+     *
+     * function greet(greeting, name) {
+     *   return greeting + ' ' + name;
+     * }
+     *
+     * var greetFred = _.partialRight(greet, 'fred');
+     * greetFred('hi');
+     * // => 'hi fred'
+     *
+     * // Partially applied with placeholders.
+     * var sayHelloTo = _.partialRight(greet, 'hello', _);
+     * sayHelloTo('fred');
+     * // => 'hello fred'
+     */
+    var partialRight = baseRest(function(func, partials) {
+      var holders = replaceHolders(partials, getHolder(partialRight));
+      return createWrap(func, WRAP_PARTIAL_RIGHT_FLAG, undefined, partials, holders);
+    });
+
+    /**
+     * Creates a function that invokes `func` with arguments arranged according
+     * to the specified `indexes` where the argument value at the first index is
+     * provided as the first argument, the argument value at the second index is
+     * provided as the second argument, and so on.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category Function
+     * @param {Function} func The function to rearrange arguments for.
+     * @param {...(number|number[])} indexes The arranged argument indexes.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var rearged = _.rearg(function(a, b, c) {
+     *   return [a, b, c];
+     * }, [2, 0, 1]);
+     *
+     * rearged('b', 'c', 'a')
+     * // => ['a', 'b', 'c']
+     */
+    var rearg = flatRest(function(func, indexes) {
+      return createWrap(func, WRAP_REARG_FLAG, undefined, undefined, undefined, indexes);
+    });
+
+    /**
+     * Creates a function that invokes `func` with the `this` binding of the
+     * created function and arguments from `start` and beyond provided as
+     * an array.
+     *
+     * **Note:** This method is based on the
+     * [rest parameter](https://mdn.io/rest_parameters).
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Function
+     * @param {Function} func The function to apply a rest parameter to.
+     * @param {number} [start=func.length-1] The start position of the rest parameter.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var say = _.rest(function(what, names) {
+     *   return what + ' ' + _.initial(names).join(', ') +
+     *     (_.size(names) > 1 ? ', & ' : '') + _.last(names);
+     * });
+     *
+     * say('hello', 'fred', 'barney', 'pebbles');
+     * // => 'hello fred, barney, & pebbles'
+     */
+    function rest(func, start) {
+      if (typeof func != 'function') {
+        throw new TypeError(FUNC_ERROR_TEXT);
       }
-      return baseFlatten(array, isShallow);
+      start = start === undefined ? start : toInteger(start);
+      return baseRest(func, start);
     }
 
     /**
-     * Gets the index at which the first occurrence of `value` is found using
-     * strict equality for comparisons, i.e. `===`. If the array is already sorted
-     * providing `true` for `fromIndex` will run a faster binary search.
+     * Creates a function that invokes `func` with the `this` binding of the
+     * create function and an array of arguments much like
+     * [`Function#apply`](http://www.ecma-international.org/ecma-262/7.0/#sec-function.prototype.apply).
+     *
+     * **Note:** This method is based on the
+     * [spread operator](https://mdn.io/spread_operator).
      *
      * @static
      * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to search.
-     * @param {*} value The value to search for.
-     * @param {boolean|number} [fromIndex=0] The index to search from or `true`
-     *  to perform a binary search on a sorted array.
-     * @returns {number} Returns the index of the matched value or `-1`.
+     * @since 3.2.0
+     * @category Function
+     * @param {Function} func The function to spread arguments over.
+     * @param {number} [start=0] The start position of the spread.
+     * @returns {Function} Returns the new function.
      * @example
      *
-     * _.indexOf([1, 2, 3, 1, 2, 3], 2);
-     * // => 1
+     * var say = _.spread(function(who, what) {
+     *   return who + ' says ' + what;
+     * });
      *
-     * _.indexOf([1, 2, 3, 1, 2, 3], 2, 3);
-     * // => 4
+     * say(['fred', 'hello']);
+     * // => 'fred says hello'
      *
-     * _.indexOf([1, 1, 2, 2, 3, 3], 2, true);
-     * // => 2
+     * var numbers = Promise.all([
+     *   Promise.resolve(40),
+     *   Promise.resolve(36)
+     * ]);
+     *
+     * numbers.then(_.spread(function(x, y) {
+     *   return x + y;
+     * }));
+     * // => a Promise of 76
      */
-    function indexOf(array, value, fromIndex) {
-      if (typeof fromIndex == 'number') {
-        var length = array ? array.length : 0;
-        fromIndex = (fromIndex < 0 ? nativeMax(0, length + fromIndex) : fromIndex || 0);
-      } else if (fromIndex) {
-        var index = sortedIndex(array, value);
-        return array[index] === value ? index : -1;
+    function spread(func, start) {
+      if (typeof func != 'function') {
+        throw new TypeError(FUNC_ERROR_TEXT);
       }
-      return baseIndexOf(array, value, fromIndex);
+      start = start == null ? 0 : nativeMax(toInteger(start), 0);
+      return baseRest(function(args) {
+        var array = args[start],
+            otherArgs = castSlice(args, 0, start);
+
+        if (array) {
+          arrayPush(otherArgs, array);
+        }
+        return apply(func, this, otherArgs);
+      });
     }
 
     /**
-     * Gets all but the last element or last `n` elements of an array. If a
-     * callback is provided elements at the end of the array are excluded from
-     * the result as long as the callback returns truey. The callback is bound
-     * to `thisArg` and invoked with three arguments; (value, index, array).
+     * Creates a throttled function that only invokes `func` at most once per
+     * every `wait` milliseconds. The throttled function comes with a `cancel`
+     * method to cancel delayed `func` invocations and a `flush` method to
+     * immediately invoke them. Provide `options` to indicate whether `func`
+     * should be invoked on the leading and/or trailing edge of the `wait`
+     * timeout. The `func` is invoked with the last arguments provided to the
+     * throttled function. Subsequent calls to the throttled function return the
+     * result of the last `func` invocation.
+     *
+     * **Note:** If `leading` and `trailing` options are `true`, `func` is
+     * invoked on the trailing edge of the timeout only if the throttled function
+     * is invoked more than once during the `wait` timeout.
      *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
+     * If `wait` is `0` and `leading` is `false`, `func` invocation is deferred
+     * until to the next tick, similar to `setTimeout` with a timeout of `0`.
      *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * See [David Corbacho's article](https://css-tricks.com/debouncing-throttling-explained-examples/)
+     * for details over the differences between `_.throttle` and `_.debounce`.
      *
      * @static
      * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to query.
-     * @param {Function|Object|number|string} [callback=1] The function called
-     *  per element or the number of elements to exclude. If a property name or
-     *  object is provided it will be used to create a "_.pluck" or "_.where"
-     *  style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a slice of `array`.
+     * @since 0.1.0
+     * @category Function
+     * @param {Function} func The function to throttle.
+     * @param {number} [wait=0] The number of milliseconds to throttle invocations to.
+     * @param {Object} [options={}] The options object.
+     * @param {boolean} [options.leading=true]
+     *  Specify invoking on the leading edge of the timeout.
+     * @param {boolean} [options.trailing=true]
+     *  Specify invoking on the trailing edge of the timeout.
+     * @returns {Function} Returns the new throttled function.
      * @example
      *
-     * _.initial([1, 2, 3]);
-     * // => [1, 2]
+     * // Avoid excessively updating the position while scrolling.
+     * jQuery(window).on('scroll', _.throttle(updatePosition, 100));
      *
-     * _.initial([1, 2, 3], 2);
-     * // => [1]
+     * // Invoke `renewToken` when the click event is fired, but not more than once every 5 minutes.
+     * var throttled = _.throttle(renewToken, 300000, { 'trailing': false });
+     * jQuery(element).on('click', throttled);
+     *
+     * // Cancel the trailing throttled invocation.
+     * jQuery(window).on('popstate', throttled.cancel);
+     */
+    function throttle(func, wait, options) {
+      var leading = true,
+          trailing = true;
+
+      if (typeof func != 'function') {
+        throw new TypeError(FUNC_ERROR_TEXT);
+      }
+      if (isObject(options)) {
+        leading = 'leading' in options ? !!options.leading : leading;
+        trailing = 'trailing' in options ? !!options.trailing : trailing;
+      }
+      return debounce(func, wait, {
+        'leading': leading,
+        'maxWait': wait,
+        'trailing': trailing
+      });
+    }
+
+    /**
+     * Creates a function that accepts up to one argument, ignoring any
+     * additional arguments.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Function
+     * @param {Function} func The function to cap arguments for.
+     * @returns {Function} Returns the new capped function.
+     * @example
+     *
+     * _.map(['6', '8', '10'], _.unary(parseInt));
+     * // => [6, 8, 10]
+     */
+    function unary(func) {
+      return ary(func, 1);
+    }
+
+    /**
+     * Creates a function that provides `value` to `wrapper` as its first
+     * argument. Any additional arguments provided to the function are appended
+     * to those provided to the `wrapper`. The wrapper is invoked with the `this`
+     * binding of the created function.
+     *
+     * @static
+     * @memberOf _
+     * @since 0.1.0
+     * @category Function
+     * @param {*} value The value to wrap.
+     * @param {Function} [wrapper=identity] The wrapper function.
+     * @returns {Function} Returns the new function.
+     * @example
      *
-     * _.initial([1, 2, 3], function(num) {
-     *   return num > 1;
+     * var p = _.wrap(_.escape, function(func, text) {
+     *   return '<p>' + func(text) + '</p>';
      * });
+     *
+     * p('fred, barney, & pebbles');
+     * // => '<p>fred, barney, &amp; pebbles</p>'
+     */
+    function wrap(value, wrapper) {
+      return partial(castFunction(wrapper), value);
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Casts `value` as an array if it's not one.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.4.0
+     * @category Lang
+     * @param {*} value The value to inspect.
+     * @returns {Array} Returns the cast array.
+     * @example
+     *
+     * _.castArray(1);
      * // => [1]
      *
-     * var characters = [
-     *   { 'name': 'barney',  'blocked': false, 'employer': 'slate' },
-     *   { 'name': 'fred',    'blocked': true,  'employer': 'slate' },
-     *   { 'name': 'pebbles', 'blocked': true,  'employer': 'na' }
-     * ];
+     * _.castArray({ 'a': 1 });
+     * // => [{ 'a': 1 }]
      *
-     * // using "_.pluck" callback shorthand
-     * _.initial(characters, 'blocked');
-     * // => [{ 'name': 'barney',  'blocked': false, 'employer': 'slate' }]
+     * _.castArray('abc');
+     * // => ['abc']
      *
-     * // using "_.where" callback shorthand
-     * _.pluck(_.initial(characters, { 'employer': 'na' }), 'name');
-     * // => ['barney', 'fred']
+     * _.castArray(null);
+     * // => [null]
+     *
+     * _.castArray(undefined);
+     * // => [undefined]
+     *
+     * _.castArray();
+     * // => []
+     *
+     * var array = [1, 2, 3];
+     * console.log(_.castArray(array) === array);
+     * // => true
      */
-    function initial(array, callback, thisArg) {
-      var n = 0,
-          length = array ? array.length : 0;
-
-      if (typeof callback != 'number' && callback != null) {
-        var index = length;
-        callback = lodash.createCallback(callback, thisArg, 3);
-        while (index-- && callback(array[index], index, array)) {
-          n++;
-        }
-      } else {
-        n = (callback == null || thisArg) ? 1 : callback || n;
+    function castArray() {
+      if (!arguments.length) {
+        return [];
       }
-      return slice(array, 0, nativeMin(nativeMax(0, length - n), length));
+      var value = arguments[0];
+      return isArray(value) ? value : [value];
     }
 
     /**
-     * Creates an array of unique values present in all provided arrays using
-     * strict equality for comparisons, i.e. `===`.
+     * Creates a shallow clone of `value`.
+     *
+     * **Note:** This method is loosely based on the
+     * [structured clone algorithm](https://mdn.io/Structured_clone_algorithm)
+     * and supports cloning arrays, array buffers, booleans, date objects, maps,
+     * numbers, `Object` objects, regexes, sets, strings, symbols, and typed
+     * arrays. The own enumerable properties of `arguments` objects are cloned
+     * as plain objects. An empty object is returned for uncloneable values such
+     * as error objects, functions, DOM nodes, and WeakMaps.
      *
      * @static
      * @memberOf _
-     * @category Arrays
-     * @param {...Array} [array] The arrays to inspect.
-     * @returns {Array} Returns an array of shared values.
+     * @since 0.1.0
+     * @category Lang
+     * @param {*} value The value to clone.
+     * @returns {*} Returns the cloned value.
+     * @see _.cloneDeep
      * @example
      *
-     * _.intersection([1, 2, 3], [5, 2, 1, 4], [2, 1]);
-     * // => [1, 2]
+     * var objects = [{ 'a': 1 }, { 'b': 2 }];
+     *
+     * var shallow = _.clone(objects);
+     * console.log(shallow[0] === objects[0]);
+     * // => true
      */
-    function intersection() {
-      var args = [],
-          argsIndex = -1,
-          argsLength = arguments.length,
-          caches = getArray(),
-          indexOf = getIndexOf(),
-          trustIndexOf = indexOf === baseIndexOf,
-          seen = getArray();
-
-      while (++argsIndex < argsLength) {
-        var value = arguments[argsIndex];
-        if (isArray(value) || isArguments(value)) {
-          args.push(value);
-          caches.push(trustIndexOf && value.length >= largeArraySize &&
-            createCache(argsIndex ? args[argsIndex] : seen));
-        }
-      }
-      var array = args[0],
-          index = -1,
-          length = array ? array.length : 0,
-          result = [];
+    function clone(value) {
+      return baseClone(value, CLONE_SYMBOLS_FLAG);
+    }
 
-      outer:
-      while (++index < length) {
-        var cache = caches[0];
-        value = array[index];
+    /**
+     * This method is like `_.clone` except that it accepts `customizer` which
+     * is invoked to produce the cloned value. If `customizer` returns `undefined`,
+     * cloning is handled by the method instead. The `customizer` is invoked with
+     * up to four arguments; (value [, index|key, object, stack]).
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Lang
+     * @param {*} value The value to clone.
+     * @param {Function} [customizer] The function to customize cloning.
+     * @returns {*} Returns the cloned value.
+     * @see _.cloneDeepWith
+     * @example
+     *
+     * function customizer(value) {
+     *   if (_.isElement(value)) {
+     *     return value.cloneNode(false);
+     *   }
+     * }
+     *
+     * var el = _.cloneWith(document.body, customizer);
+     *
+     * console.log(el === document.body);
+     * // => false
+     * console.log(el.nodeName);
+     * // => 'BODY'
+     * console.log(el.childNodes.length);
+     * // => 0
+     */
+    function cloneWith(value, customizer) {
+      customizer = typeof customizer == 'function' ? customizer : undefined;
+      return baseClone(value, CLONE_SYMBOLS_FLAG, customizer);
+    }
 
-        if ((cache ? cacheIndexOf(cache, value) : indexOf(seen, value)) < 0) {
-          argsIndex = argsLength;
-          (cache || seen).push(value);
-          while (--argsIndex) {
-            cache = caches[argsIndex];
-            if ((cache ? cacheIndexOf(cache, value) : indexOf(args[argsIndex], value)) < 0) {
-              continue outer;
-            }
-          }
-          result.push(value);
-        }
-      }
-      while (argsLength--) {
-        cache = caches[argsLength];
-        if (cache) {
-          releaseObject(cache);
-        }
-      }
-      releaseArray(caches);
-      releaseArray(seen);
-      return result;
+    /**
+     * This method is like `_.clone` except that it recursively clones `value`.
+     *
+     * @static
+     * @memberOf _
+     * @since 1.0.0
+     * @category Lang
+     * @param {*} value The value to recursively clone.
+     * @returns {*} Returns the deep cloned value.
+     * @see _.clone
+     * @example
+     *
+     * var objects = [{ 'a': 1 }, { 'b': 2 }];
+     *
+     * var deep = _.cloneDeep(objects);
+     * console.log(deep[0] === objects[0]);
+     * // => false
+     */
+    function cloneDeep(value) {
+      return baseClone(value, CLONE_DEEP_FLAG | CLONE_SYMBOLS_FLAG);
     }
 
     /**
-     * Gets the last element or last `n` elements of an array. If a callback is
-     * provided elements at the end of the array are returned as long as the
-     * callback returns truey. The callback is bound to `thisArg` and invoked
-     * with three arguments; (value, index, array).
+     * This method is like `_.cloneWith` except that it recursively clones `value`.
      *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Lang
+     * @param {*} value The value to recursively clone.
+     * @param {Function} [customizer] The function to customize cloning.
+     * @returns {*} Returns the deep cloned value.
+     * @see _.cloneWith
+     * @example
+     *
+     * function customizer(value) {
+     *   if (_.isElement(value)) {
+     *     return value.cloneNode(true);
+     *   }
+     * }
      *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * var el = _.cloneDeepWith(document.body, customizer);
+     *
+     * console.log(el === document.body);
+     * // => false
+     * console.log(el.nodeName);
+     * // => 'BODY'
+     * console.log(el.childNodes.length);
+     * // => 20
+     */
+    function cloneDeepWith(value, customizer) {
+      customizer = typeof customizer == 'function' ? customizer : undefined;
+      return baseClone(value, CLONE_DEEP_FLAG | CLONE_SYMBOLS_FLAG, customizer);
+    }
+
+    /**
+     * Checks if `object` conforms to `source` by invoking the predicate
+     * properties of `source` with the corresponding property values of `object`.
+     *
+     * **Note:** This method is equivalent to `_.conforms` when `source` is
+     * partially applied.
      *
      * @static
      * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to query.
-     * @param {Function|Object|number|string} [callback] The function called
-     *  per element or the number of elements to return. If a property name or
-     *  object is provided it will be used to create a "_.pluck" or "_.where"
-     *  style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the last element(s) of `array`.
+     * @since 4.14.0
+     * @category Lang
+     * @param {Object} object The object to inspect.
+     * @param {Object} source The object of property predicates to conform to.
+     * @returns {boolean} Returns `true` if `object` conforms, else `false`.
      * @example
      *
-     * _.last([1, 2, 3]);
-     * // => 3
+     * var object = { 'a': 1, 'b': 2 };
      *
-     * _.last([1, 2, 3], 2);
-     * // => [2, 3]
+     * _.conformsTo(object, { 'b': function(n) { return n > 1; } });
+     * // => true
      *
-     * _.last([1, 2, 3], function(num) {
-     *   return num > 1;
-     * });
-     * // => [2, 3]
+     * _.conformsTo(object, { 'b': function(n) { return n > 2; } });
+     * // => false
+     */
+    function conformsTo(object, source) {
+      return source == null || baseConformsTo(object, source, keys(source));
+    }
+
+    /**
+     * Performs a
+     * [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
+     * comparison between two values to determine if they are equivalent.
      *
-     * var characters = [
-     *   { 'name': 'barney',  'blocked': false, 'employer': 'slate' },
-     *   { 'name': 'fred',    'blocked': true,  'employer': 'slate' },
-     *   { 'name': 'pebbles', 'blocked': true,  'employer': 'na' }
-     * ];
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Lang
+     * @param {*} value The value to compare.
+     * @param {*} other The other value to compare.
+     * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
+     * @example
      *
-     * // using "_.pluck" callback shorthand
-     * _.pluck(_.last(characters, 'blocked'), 'name');
-     * // => ['fred', 'pebbles']
-     *
-     * // using "_.where" callback shorthand
-     * _.last(characters, { 'employer': 'na' });
-     * // => [{ 'name': 'pebbles', 'blocked': true, 'employer': 'na' }]
-     */
-    function last(array, callback, thisArg) {
-      var n = 0,
-          length = array ? array.length : 0;
-
-      if (typeof callback != 'number' && callback != null) {
-        var index = length;
-        callback = lodash.createCallback(callback, thisArg, 3);
-        while (index-- && callback(array[index], index, array)) {
-          n++;
-        }
-      } else {
-        n = callback;
-        if (n == null || thisArg) {
-          return array ? array[length - 1] : undefined;
-        }
-      }
-      return slice(array, nativeMax(0, length - n));
+     * var object = { 'a': 1 };
+     * var other = { 'a': 1 };
+     *
+     * _.eq(object, object);
+     * // => true
+     *
+     * _.eq(object, other);
+     * // => false
+     *
+     * _.eq('a', 'a');
+     * // => true
+     *
+     * _.eq('a', Object('a'));
+     * // => false
+     *
+     * _.eq(NaN, NaN);
+     * // => true
+     */
+    function eq(value, other) {
+      return value === other || (value !== value && other !== other);
     }
 
     /**
-     * Gets the index at which the last occurrence of `value` is found using strict
-     * equality for comparisons, i.e. `===`. If `fromIndex` is negative, it is used
-     * as the offset from the end of the collection.
+     * Checks if `value` is greater than `other`.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.9.0
+     * @category Lang
+     * @param {*} value The value to compare.
+     * @param {*} other The other value to compare.
+     * @returns {boolean} Returns `true` if `value` is greater than `other`,
+     *  else `false`.
+     * @see _.lt
+     * @example
      *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
+     * _.gt(3, 1);
+     * // => true
+     *
+     * _.gt(3, 3);
+     * // => false
      *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * _.gt(1, 3);
+     * // => false
+     */
+    var gt = createRelationalOperation(baseGt);
+
+    /**
+     * Checks if `value` is greater than or equal to `other`.
      *
      * @static
      * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to search.
-     * @param {*} value The value to search for.
-     * @param {number} [fromIndex=array.length-1] The index to search from.
-     * @returns {number} Returns the index of the matched value or `-1`.
+     * @since 3.9.0
+     * @category Lang
+     * @param {*} value The value to compare.
+     * @param {*} other The other value to compare.
+     * @returns {boolean} Returns `true` if `value` is greater than or equal to
+     *  `other`, else `false`.
+     * @see _.lte
      * @example
      *
-     * _.lastIndexOf([1, 2, 3, 1, 2, 3], 2);
-     * // => 4
+     * _.gte(3, 1);
+     * // => true
      *
-     * _.lastIndexOf([1, 2, 3, 1, 2, 3], 2, 3);
-     * // => 1
+     * _.gte(3, 3);
+     * // => true
+     *
+     * _.gte(1, 3);
+     * // => false
      */
-    function lastIndexOf(array, value, fromIndex) {
-      var index = array ? array.length : 0;
-      if (typeof fromIndex == 'number') {
-        index = (fromIndex < 0 ? nativeMax(0, index + fromIndex) : nativeMin(fromIndex, index - 1)) + 1;
-      }
-      while (index--) {
-        if (array[index] === value) {
-          return index;
-        }
-      }
-      return -1;
+    var gte = createRelationalOperation(function(value, other) {
+      return value >= other;
+    });
+
+    /**
+     * Checks if `value` is likely an `arguments` object.
+     *
+     * @static
+     * @memberOf _
+     * @since 0.1.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is an `arguments` object,
+     *  else `false`.
+     * @example
+     *
+     * _.isArguments(function() { return arguments; }());
+     * // => true
+     *
+     * _.isArguments([1, 2, 3]);
+     * // => false
+     */
+    var isArguments = baseIsArguments(function() { return arguments; }()) ? baseIsArguments : function(value) {
+      return isObjectLike(value) && hasOwnProperty.call(value, 'callee') &&
+        !propertyIsEnumerable.call(value, 'callee');
+    };
+
+    /**
+     * Checks if `value` is classified as an `Array` object.
+     *
+     * @static
+     * @memberOf _
+     * @since 0.1.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is an array, else `false`.
+     * @example
+     *
+     * _.isArray([1, 2, 3]);
+     * // => true
+     *
+     * _.isArray(document.body.children);
+     * // => false
+     *
+     * _.isArray('abc');
+     * // => false
+     *
+     * _.isArray(_.noop);
+     * // => false
+     */
+    var isArray = Array.isArray;
+
+    /**
+     * Checks if `value` is classified as an `ArrayBuffer` object.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.3.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is an array buffer, else `false`.
+     * @example
+     *
+     * _.isArrayBuffer(new ArrayBuffer(2));
+     * // => true
+     *
+     * _.isArrayBuffer(new Array(2));
+     * // => false
+     */
+    var isArrayBuffer = nodeIsArrayBuffer ? baseUnary(nodeIsArrayBuffer) : baseIsArrayBuffer;
+
+    /**
+     * Checks if `value` is array-like. A value is considered array-like if it's
+     * not a function and has a `value.length` that's an integer greater than or
+     * equal to `0` and less than or equal to `Number.MAX_SAFE_INTEGER`.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is array-like, else `false`.
+     * @example
+     *
+     * _.isArrayLike([1, 2, 3]);
+     * // => true
+     *
+     * _.isArrayLike(document.body.children);
+     * // => true
+     *
+     * _.isArrayLike('abc');
+     * // => true
+     *
+     * _.isArrayLike(_.noop);
+     * // => false
+     */
+    function isArrayLike(value) {
+      return value != null && isLength(value.length) && !isFunction(value);
     }
 
     /**
-     * Removes all provided values from the given array using strict equality for
-     * comparisons, i.e. `===`.
+     * This method is like `_.isArrayLike` except that it also checks if `value`
+     * is an object.
      *
      * @static
      * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to modify.
-     * @param {...*} [value] The values to remove.
-     * @returns {Array} Returns `array`.
+     * @since 4.0.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is an array-like object,
+     *  else `false`.
      * @example
      *
-     * var array = [1, 2, 3, 1, 2, 3];
-     * _.pull(array, 2, 3);
-     * console.log(array);
-     * // => [1, 1]
+     * _.isArrayLikeObject([1, 2, 3]);
+     * // => true
+     *
+     * _.isArrayLikeObject(document.body.children);
+     * // => true
+     *
+     * _.isArrayLikeObject('abc');
+     * // => false
+     *
+     * _.isArrayLikeObject(_.noop);
+     * // => false
      */
-    function pull(array) {
-      var args = arguments,
-          argsIndex = 0,
-          argsLength = args.length,
-          length = array ? array.length : 0;
+    function isArrayLikeObject(value) {
+      return isObjectLike(value) && isArrayLike(value);
+    }
 
-      while (++argsIndex < argsLength) {
-        var index = -1,
-            value = args[argsIndex];
-        while (++index < length) {
-          if (array[index] === value) {
-            splice.call(array, index--, 1);
-            length--;
-          }
-        }
-      }
-      return array;
+    /**
+     * Checks if `value` is classified as a boolean primitive or object.
+     *
+     * @static
+     * @memberOf _
+     * @since 0.1.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a boolean, else `false`.
+     * @example
+     *
+     * _.isBoolean(false);
+     * // => true
+     *
+     * _.isBoolean(null);
+     * // => false
+     */
+    function isBoolean(value) {
+      return value === true || value === false ||
+        (isObjectLike(value) && baseGetTag(value) == boolTag);
     }
 
     /**
-     * Creates an array of numbers (positive and/or negative) progressing from
-     * `start` up to but not including `end`. If `start` is less than `stop` a
-     * zero-length range is created unless a negative `step` is specified.
+     * Checks if `value` is a buffer.
      *
      * @static
      * @memberOf _
-     * @category Arrays
-     * @param {number} [start=0] The start of the range.
-     * @param {number} end The end of the range.
-     * @param {number} [step=1] The value to increment or decrement by.
-     * @returns {Array} Returns a new range array.
+     * @since 4.3.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a buffer, else `false`.
      * @example
      *
-     * _.range(4);
-     * // => [0, 1, 2, 3]
+     * _.isBuffer(new Buffer(2));
+     * // => true
      *
-     * _.range(1, 5);
-     * // => [1, 2, 3, 4]
+     * _.isBuffer(new Uint8Array(2));
+     * // => false
+     */
+    var isBuffer = nativeIsBuffer || stubFalse;
+
+    /**
+     * Checks if `value` is classified as a `Date` object.
      *
-     * _.range(0, 20, 5);
-     * // => [0, 5, 10, 15]
+     * @static
+     * @memberOf _
+     * @since 0.1.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a date object, else `false`.
+     * @example
      *
-     * _.range(0, -4, -1);
-     * // => [0, -1, -2, -3]
+     * _.isDate(new Date);
+     * // => true
      *
-     * _.range(1, 4, 0);
-     * // => [1, 1, 1]
+     * _.isDate('Mon April 23 2012');
+     * // => false
+     */
+    var isDate = nodeIsDate ? baseUnary(nodeIsDate) : baseIsDate;
+
+    /**
+     * Checks if `value` is likely a DOM element.
      *
-     * _.range(0);
-     * // => []
+     * @static
+     * @memberOf _
+     * @since 0.1.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a DOM element, else `false`.
+     * @example
+     *
+     * _.isElement(document.body);
+     * // => true
+     *
+     * _.isElement('<body>');
+     * // => false
      */
-    function range(start, end, step) {
-      start = +start || 0;
-      step = typeof step == 'number' ? step : (+step || 1);
+    function isElement(value) {
+      return isObjectLike(value) && value.nodeType === 1 && !isPlainObject(value);
+    }
 
-      if (end == null) {
-        end = start;
-        start = 0;
+    /**
+     * Checks if `value` is an empty object, collection, map, or set.
+     *
+     * Objects are considered empty if they have no own enumerable string keyed
+     * properties.
+     *
+     * Array-like values such as `arguments` objects, arrays, buffers, strings, or
+     * jQuery-like collections are considered empty if they have a `length` of `0`.
+     * Similarly, maps and sets are considered empty if they have a `size` of `0`.
+     *
+     * @static
+     * @memberOf _
+     * @since 0.1.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is empty, else `false`.
+     * @example
+     *
+     * _.isEmpty(null);
+     * // => true
+     *
+     * _.isEmpty(true);
+     * // => true
+     *
+     * _.isEmpty(1);
+     * // => true
+     *
+     * _.isEmpty([1, 2, 3]);
+     * // => false
+     *
+     * _.isEmpty({ 'a': 1 });
+     * // => false
+     */
+    function isEmpty(value) {
+      if (value == null) {
+        return true;
       }
-      // use `Array(length)` so engines like Chakra and V8 avoid slower modes
-      // http://youtu.be/XAqIpGU8ZZk#t=17m25s
-      var index = -1,
-          length = nativeMax(0, ceil((end - start) / (step || 1))),
-          result = Array(length);
-
-      while (++index < length) {
-        result[index] = start;
-        start += step;
+      if (isArrayLike(value) &&
+          (isArray(value) || typeof value == 'string' || typeof value.splice == 'function' ||
+            isBuffer(value) || isTypedArray(value) || isArguments(value))) {
+        return !value.length;
+      }
+      var tag = getTag(value);
+      if (tag == mapTag || tag == setTag) {
+        return !value.size;
       }
-      return result;
+      if (isPrototype(value)) {
+        return !baseKeys(value).length;
+      }
+      for (var key in value) {
+        if (hasOwnProperty.call(value, key)) {
+          return false;
+        }
+      }
+      return true;
     }
 
     /**
-     * Removes all elements from an array that the callback returns truey for
-     * and returns an array of removed elements. The callback is bound to `thisArg`
-     * and invoked with three arguments; (value, index, array).
+     * Performs a deep comparison between two values to determine if they are
+     * equivalent.
+     *
+     * **Note:** This method supports comparing arrays, array buffers, booleans,
+     * date objects, error objects, maps, numbers, `Object` objects, regexes,
+     * sets, strings, symbols, and typed arrays. `Object` objects are compared
+     * by their own, not inherited, enumerable properties. Functions and DOM
+     * nodes are compared by strict equality, i.e. `===`.
      *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
+     * @static
+     * @memberOf _
+     * @since 0.1.0
+     * @category Lang
+     * @param {*} value The value to compare.
+     * @param {*} other The other value to compare.
+     * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
+     * @example
      *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * var object = { 'a': 1 };
+     * var other = { 'a': 1 };
+     *
+     * _.isEqual(object, other);
+     * // => true
+     *
+     * object === other;
+     * // => false
+     */
+    function isEqual(value, other) {
+      return baseIsEqual(value, other);
+    }
+
+    /**
+     * This method is like `_.isEqual` except that it accepts `customizer` which
+     * is invoked to compare values. If `customizer` returns `undefined`, comparisons
+     * are handled by the method instead. The `customizer` is invoked with up to
+     * six arguments: (objValue, othValue [, index|key, object, other, stack]).
      *
      * @static
      * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to modify.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a new array of removed elements.
+     * @since 4.0.0
+     * @category Lang
+     * @param {*} value The value to compare.
+     * @param {*} other The other value to compare.
+     * @param {Function} [customizer] The function to customize comparisons.
+     * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
      * @example
      *
-     * var array = [1, 2, 3, 4, 5, 6];
-     * var evens = _.remove(array, function(num) { return num % 2 == 0; });
+     * function isGreeting(value) {
+     *   return /^h(?:i|ello)$/.test(value);
+     * }
      *
-     * console.log(array);
-     * // => [1, 3, 5]
+     * function customizer(objValue, othValue) {
+     *   if (isGreeting(objValue) && isGreeting(othValue)) {
+     *     return true;
+     *   }
+     * }
      *
-     * console.log(evens);
-     * // => [2, 4, 6]
+     * var array = ['hello', 'goodbye'];
+     * var other = ['hi', 'goodbye'];
+     *
+     * _.isEqualWith(array, other, customizer);
+     * // => true
      */
-    function remove(array, callback, thisArg) {
-      var index = -1,
-          length = array ? array.length : 0,
-          result = [];
+    function isEqualWith(value, other, customizer) {
+      customizer = typeof customizer == 'function' ? customizer : undefined;
+      var result = customizer ? customizer(value, other) : undefined;
+      return result === undefined ? baseIsEqual(value, other, undefined, customizer) : !!result;
+    }
 
-      callback = lodash.createCallback(callback, thisArg, 3);
-      while (++index < length) {
-        var value = array[index];
-        if (callback(value, index, array)) {
-          result.push(value);
-          splice.call(array, index--, 1);
-          length--;
-        }
+    /**
+     * Checks if `value` is an `Error`, `EvalError`, `RangeError`, `ReferenceError`,
+     * `SyntaxError`, `TypeError`, or `URIError` object.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is an error object, else `false`.
+     * @example
+     *
+     * _.isError(new Error);
+     * // => true
+     *
+     * _.isError(Error);
+     * // => false
+     */
+    function isError(value) {
+      if (!isObjectLike(value)) {
+        return false;
       }
-      return result;
+      var tag = baseGetTag(value);
+      return tag == errorTag || tag == domExcTag ||
+        (typeof value.message == 'string' && typeof value.name == 'string' && !isPlainObject(value));
     }
 
     /**
-     * The opposite of `_.initial` this method gets all but the first element or
-     * first `n` elements of an array. If a callback function is provided elements
-     * at the beginning of the array are excluded from the result as long as the
-     * callback returns truey. The callback is bound to `thisArg` and invoked
-     * with three arguments; (value, index, array).
+     * Checks if `value` is a finite primitive number.
+     *
+     * **Note:** This method is based on
+     * [`Number.isFinite`](https://mdn.io/Number/isFinite).
+     *
+     * @static
+     * @memberOf _
+     * @since 0.1.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a finite number, else `false`.
+     * @example
+     *
+     * _.isFinite(3);
+     * // => true
+     *
+     * _.isFinite(Number.MIN_VALUE);
+     * // => true
      *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
+     * _.isFinite(Infinity);
+     * // => false
      *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * _.isFinite('3');
+     * // => false
+     */
+    function isFinite(value) {
+      return typeof value == 'number' && nativeIsFinite(value);
+    }
+
+    /**
+     * Checks if `value` is classified as a `Function` object.
      *
      * @static
      * @memberOf _
-     * @alias drop, tail
-     * @category Arrays
-     * @param {Array} array The array to query.
-     * @param {Function|Object|number|string} [callback=1] The function called
-     *  per element or the number of elements to exclude. If a property name or
-     *  object is provided it will be used to create a "_.pluck" or "_.where"
-     *  style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a slice of `array`.
+     * @since 0.1.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a function, else `false`.
      * @example
      *
-     * _.rest([1, 2, 3]);
-     * // => [2, 3]
+     * _.isFunction(_);
+     * // => true
      *
-     * _.rest([1, 2, 3], 2);
-     * // => [3]
+     * _.isFunction(/abc/);
+     * // => false
+     */
+    function isFunction(value) {
+      if (!isObject(value)) {
+        return false;
+      }
+      // The use of `Object#toString` avoids issues with the `typeof` operator
+      // in Safari 9 which returns 'object' for typed arrays and other constructors.
+      var tag = baseGetTag(value);
+      return tag == funcTag || tag == genTag || tag == asyncTag || tag == proxyTag;
+    }
+
+    /**
+     * Checks if `value` is an integer.
      *
-     * _.rest([1, 2, 3], function(num) {
-     *   return num < 3;
-     * });
-     * // => [3]
+     * **Note:** This method is based on
+     * [`Number.isInteger`](https://mdn.io/Number/isInteger).
      *
-     * var characters = [
-     *   { 'name': 'barney',  'blocked': true,  'employer': 'slate' },
-     *   { 'name': 'fred',    'blocked': false,  'employer': 'slate' },
-     *   { 'name': 'pebbles', 'blocked': true, 'employer': 'na' }
-     * ];
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is an integer, else `false`.
+     * @example
      *
-     * // using "_.pluck" callback shorthand
-     * _.pluck(_.rest(characters, 'blocked'), 'name');
-     * // => ['fred', 'pebbles']
-     *
-     * // using "_.where" callback shorthand
-     * _.rest(characters, { 'employer': 'slate' });
-     * // => [{ 'name': 'pebbles', 'blocked': true, 'employer': 'na' }]
-     */
-    function rest(array, callback, thisArg) {
-      if (typeof callback != 'number' && callback != null) {
-        var n = 0,
-            index = -1,
-            length = array ? array.length : 0;
+     * _.isInteger(3);
+     * // => true
+     *
+     * _.isInteger(Number.MIN_VALUE);
+     * // => false
+     *
+     * _.isInteger(Infinity);
+     * // => false
+     *
+     * _.isInteger('3');
+     * // => false
+     */
+    function isInteger(value) {
+      return typeof value == 'number' && value == toInteger(value);
+    }
 
-        callback = lodash.createCallback(callback, thisArg, 3);
-        while (++index < length && callback(array[index], index, array)) {
-          n++;
-        }
-      } else {
-        n = (callback == null || thisArg) ? 1 : nativeMax(0, callback);
-      }
-      return slice(array, n);
+    /**
+     * Checks if `value` is a valid array-like length.
+     *
+     * **Note:** This method is loosely based on
+     * [`ToLength`](http://ecma-international.org/ecma-262/7.0/#sec-tolength).
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a valid length, else `false`.
+     * @example
+     *
+     * _.isLength(3);
+     * // => true
+     *
+     * _.isLength(Number.MIN_VALUE);
+     * // => false
+     *
+     * _.isLength(Infinity);
+     * // => false
+     *
+     * _.isLength('3');
+     * // => false
+     */
+    function isLength(value) {
+      return typeof value == 'number' &&
+        value > -1 && value % 1 == 0 && value <= MAX_SAFE_INTEGER;
     }
 
     /**
-     * Uses a binary search to determine the smallest index at which a value
-     * should be inserted into a given sorted array in order to maintain the sort
-     * order of the array. If a callback is provided it will be executed for
-     * `value` and each element of `array` to compute their sort ranking. The
-     * callback is bound to `thisArg` and invoked with one argument; (value).
+     * Checks if `value` is the
+     * [language type](http://www.ecma-international.org/ecma-262/7.0/#sec-ecmascript-language-types)
+     * of `Object`. (e.g. arrays, functions, objects, regexes, `new Number(0)`, and `new String('')`)
+     *
+     * @static
+     * @memberOf _
+     * @since 0.1.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is an object, else `false`.
+     * @example
+     *
+     * _.isObject({});
+     * // => true
      *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
+     * _.isObject([1, 2, 3]);
+     * // => true
      *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * _.isObject(_.noop);
+     * // => true
+     *
+     * _.isObject(null);
+     * // => false
+     */
+    function isObject(value) {
+      var type = typeof value;
+      return value != null && (type == 'object' || type == 'function');
+    }
+
+    /**
+     * Checks if `value` is object-like. A value is object-like if it's not `null`
+     * and has a `typeof` result of "object".
      *
      * @static
      * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to inspect.
-     * @param {*} value The value to evaluate.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {number} Returns the index at which `value` should be inserted
-     *  into `array`.
+     * @since 4.0.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is object-like, else `false`.
      * @example
      *
-     * _.sortedIndex([20, 30, 50], 40);
-     * // => 2
+     * _.isObjectLike({});
+     * // => true
      *
-     * // using "_.pluck" callback shorthand
-     * _.sortedIndex([{ 'x': 20 }, { 'x': 30 }, { 'x': 50 }], { 'x': 40 }, 'x');
-     * // => 2
+     * _.isObjectLike([1, 2, 3]);
+     * // => true
      *
-     * var dict = {
-     *   'wordToNumber': { 'twenty': 20, 'thirty': 30, 'fourty': 40, 'fifty': 50 }
-     * };
+     * _.isObjectLike(_.noop);
+     * // => false
      *
-     * _.sortedIndex(['twenty', 'thirty', 'fifty'], 'fourty', function(word) {
-     *   return dict.wordToNumber[word];
-     * });
-     * // => 2
+     * _.isObjectLike(null);
+     * // => false
+     */
+    function isObjectLike(value) {
+      return value != null && typeof value == 'object';
+    }
+
+    /**
+     * Checks if `value` is classified as a `Map` object.
      *
-     * _.sortedIndex(['twenty', 'thirty', 'fifty'], 'fourty', function(word) {
-     *   return this.wordToNumber[word];
-     * }, dict);
-     * // => 2
+     * @static
+     * @memberOf _
+     * @since 4.3.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a map, else `false`.
+     * @example
+     *
+     * _.isMap(new Map);
+     * // => true
+     *
+     * _.isMap(new WeakMap);
+     * // => false
      */
-    function sortedIndex(array, value, callback, thisArg) {
-      var low = 0,
-          high = array ? array.length : low;
+    var isMap = nodeIsMap ? baseUnary(nodeIsMap) : baseIsMap;
 
-      // explicitly reference `identity` for better inlining in Firefox
-      callback = callback ? lodash.createCallback(callback, thisArg, 1) : identity;
-      value = callback(value);
+    /**
+     * Performs a partial deep comparison between `object` and `source` to
+     * determine if `object` contains equivalent property values.
+     *
+     * **Note:** This method is equivalent to `_.matches` when `source` is
+     * partially applied.
+     *
+     * Partial comparisons will match empty array and empty object `source`
+     * values against any array or object value, respectively. See `_.isEqual`
+     * for a list of supported value comparisons.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category Lang
+     * @param {Object} object The object to inspect.
+     * @param {Object} source The object of property values to match.
+     * @returns {boolean} Returns `true` if `object` is a match, else `false`.
+     * @example
+     *
+     * var object = { 'a': 1, 'b': 2 };
+     *
+     * _.isMatch(object, { 'b': 2 });
+     * // => true
+     *
+     * _.isMatch(object, { 'b': 1 });
+     * // => false
+     */
+    function isMatch(object, source) {
+      return object === source || baseIsMatch(object, source, getMatchData(source));
+    }
 
-      while (low < high) {
-        var mid = (low + high) >>> 1;
-        (callback(array[mid]) < value)
-          ? low = mid + 1
-          : high = mid;
+    /**
+     * This method is like `_.isMatch` except that it accepts `customizer` which
+     * is invoked to compare values. If `customizer` returns `undefined`, comparisons
+     * are handled by the method instead. The `customizer` is invoked with five
+     * arguments: (objValue, srcValue, index|key, object, source).
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Lang
+     * @param {Object} object The object to inspect.
+     * @param {Object} source The object of property values to match.
+     * @param {Function} [customizer] The function to customize comparisons.
+     * @returns {boolean} Returns `true` if `object` is a match, else `false`.
+     * @example
+     *
+     * function isGreeting(value) {
+     *   return /^h(?:i|ello)$/.test(value);
+     * }
+     *
+     * function customizer(objValue, srcValue) {
+     *   if (isGreeting(objValue) && isGreeting(srcValue)) {
+     *     return true;
+     *   }
+     * }
+     *
+     * var object = { 'greeting': 'hello' };
+     * var source = { 'greeting': 'hi' };
+     *
+     * _.isMatchWith(object, source, customizer);
+     * // => true
+     */
+    function isMatchWith(object, source, customizer) {
+      customizer = typeof customizer == 'function' ? customizer : undefined;
+      return baseIsMatch(object, source, getMatchData(source), customizer);
+    }
+
+    /**
+     * Checks if `value` is `NaN`.
+     *
+     * **Note:** This method is based on
+     * [`Number.isNaN`](https://mdn.io/Number/isNaN) and is not the same as
+     * global [`isNaN`](https://mdn.io/isNaN) which returns `true` for
+     * `undefined` and other non-number values.
+     *
+     * @static
+     * @memberOf _
+     * @since 0.1.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is `NaN`, else `false`.
+     * @example
+     *
+     * _.isNaN(NaN);
+     * // => true
+     *
+     * _.isNaN(new Number(NaN));
+     * // => true
+     *
+     * isNaN(undefined);
+     * // => true
+     *
+     * _.isNaN(undefined);
+     * // => false
+     */
+    function isNaN(value) {
+      // An `NaN` primitive is the only value that is not equal to itself.
+      // Perform the `toStringTag` check first to avoid errors with some
+      // ActiveX objects in IE.
+      return isNumber(value) && value != +value;
+    }
+
+    /**
+     * Checks if `value` is a pristine native function.
+     *
+     * **Note:** This method can't reliably detect native functions in the presence
+     * of the core-js package because core-js circumvents this kind of detection.
+     * Despite multiple requests, the core-js maintainer has made it clear: any
+     * attempt to fix the detection will be obstructed. As a result, we're left
+     * with little choice but to throw an error. Unfortunately, this also affects
+     * packages, like [babel-polyfill](https://www.npmjs.com/package/babel-polyfill),
+     * which rely on core-js.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a native function,
+     *  else `false`.
+     * @example
+     *
+     * _.isNative(Array.prototype.push);
+     * // => true
+     *
+     * _.isNative(_);
+     * // => false
+     */
+    function isNative(value) {
+      if (isMaskable(value)) {
+        throw new Error(CORE_ERROR_TEXT);
       }
-      return low;
+      return baseIsNative(value);
     }
 
     /**
-     * Creates an array of unique values, in order, of the provided arrays using
-     * strict equality for comparisons, i.e. `===`.
+     * Checks if `value` is `null`.
      *
      * @static
      * @memberOf _
-     * @category Arrays
-     * @param {...Array} [array] The arrays to inspect.
-     * @returns {Array} Returns an array of combined values.
+     * @since 0.1.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is `null`, else `false`.
      * @example
      *
-     * _.union([1, 2, 3], [5, 2, 1, 4], [2, 1]);
-     * // => [1, 2, 3, 5, 4]
+     * _.isNull(null);
+     * // => true
+     *
+     * _.isNull(void 0);
+     * // => false
      */
-    function union() {
-      return baseUniq(baseFlatten(arguments, true, true));
+    function isNull(value) {
+      return value === null;
     }
 
     /**
-     * Creates a duplicate-value-free version of an array using strict equality
-     * for comparisons, i.e. `===`. If the array is sorted, providing
-     * `true` for `isSorted` will use a faster algorithm. If a callback is provided
-     * each element of `array` is passed through the callback before uniqueness
-     * is computed. The callback is bound to `thisArg` and invoked with three
-     * arguments; (value, index, array).
+     * Checks if `value` is `null` or `undefined`.
      *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is nullish, else `false`.
+     * @example
+     *
+     * _.isNil(null);
+     * // => true
+     *
+     * _.isNil(void 0);
+     * // => true
+     *
+     * _.isNil(NaN);
+     * // => false
+     */
+    function isNil(value) {
+      return value == null;
+    }
+
+    /**
+     * Checks if `value` is classified as a `Number` primitive or object.
      *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * **Note:** To exclude `Infinity`, `-Infinity`, and `NaN`, which are
+     * classified as numbers, use the `_.isFinite` method.
      *
      * @static
      * @memberOf _
-     * @alias unique
-     * @category Arrays
-     * @param {Array} array The array to process.
-     * @param {boolean} [isSorted=false] A flag to indicate that `array` is sorted.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a duplicate-value-free array.
+     * @since 0.1.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a number, else `false`.
      * @example
      *
-     * _.uniq([1, 2, 1, 3, 1]);
-     * // => [1, 2, 3]
+     * _.isNumber(3);
+     * // => true
      *
-     * _.uniq([1, 1, 2, 2, 3], true);
-     * // => [1, 2, 3]
+     * _.isNumber(Number.MIN_VALUE);
+     * // => true
+     *
+     * _.isNumber(Infinity);
+     * // => true
+     *
+     * _.isNumber('3');
+     * // => false
+     */
+    function isNumber(value) {
+      return typeof value == 'number' ||
+        (isObjectLike(value) && baseGetTag(value) == numberTag);
+    }
+
+    /**
+     * Checks if `value` is a plain object, that is, an object created by the
+     * `Object` constructor or one with a `[[Prototype]]` of `null`.
      *
-     * _.uniq(['A', 'b', 'C', 'a', 'B', 'c'], function(letter) { return letter.toLowerCase(); });
-     * // => ['A', 'b', 'C']
+     * @static
+     * @memberOf _
+     * @since 0.8.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a plain object, else `false`.
+     * @example
      *
-     * _.uniq([1, 2.5, 3, 1.5, 2, 3.5], function(num) { return this.floor(num); }, Math);
-     * // => [1, 2.5, 3]
+     * function Foo() {
+     *   this.a = 1;
+     * }
      *
-     * // using "_.pluck" callback shorthand
-     * _.uniq([{ 'x': 1 }, { 'x': 2 }, { 'x': 1 }], 'x');
-     * // => [{ 'x': 1 }, { 'x': 2 }]
+     * _.isPlainObject(new Foo);
+     * // => false
+     *
+     * _.isPlainObject([1, 2, 3]);
+     * // => false
+     *
+     * _.isPlainObject({ 'x': 0, 'y': 0 });
+     * // => true
+     *
+     * _.isPlainObject(Object.create(null));
+     * // => true
      */
-    function uniq(array, isSorted, callback, thisArg) {
-      // juggle arguments
-      if (typeof isSorted != 'boolean' && isSorted != null) {
-        thisArg = callback;
-        callback = (typeof isSorted != 'function' && thisArg && thisArg[isSorted] === array) ? null : isSorted;
-        isSorted = false;
+    function isPlainObject(value) {
+      if (!isObjectLike(value) || baseGetTag(value) != objectTag) {
+        return false;
       }
-      if (callback != null) {
-        callback = lodash.createCallback(callback, thisArg, 3);
+      var proto = getPrototype(value);
+      if (proto === null) {
+        return true;
       }
-      return baseUniq(array, isSorted, callback);
+      var Ctor = hasOwnProperty.call(proto, 'constructor') && proto.constructor;
+      return typeof Ctor == 'function' && Ctor instanceof Ctor &&
+        funcToString.call(Ctor) == objectCtorString;
     }
 
     /**
-     * Creates an array excluding all provided values using strict equality for
-     * comparisons, i.e. `===`.
+     * Checks if `value` is classified as a `RegExp` object.
+     *
+     * @static
+     * @memberOf _
+     * @since 0.1.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a regexp, else `false`.
+     * @example
+     *
+     * _.isRegExp(/abc/);
+     * // => true
+     *
+     * _.isRegExp('/abc/');
+     * // => false
+     */
+    var isRegExp = nodeIsRegExp ? baseUnary(nodeIsRegExp) : baseIsRegExp;
+
+    /**
+     * Checks if `value` is a safe integer. An integer is safe if it's an IEEE-754
+     * double precision number which isn't the result of a rounded unsafe integer.
+     *
+     * **Note:** This method is based on
+     * [`Number.isSafeInteger`](https://mdn.io/Number/isSafeInteger).
      *
      * @static
      * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to filter.
-     * @param {...*} [value] The values to exclude.
-     * @returns {Array} Returns a new array of filtered values.
+     * @since 4.0.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a safe integer, else `false`.
      * @example
      *
-     * _.without([1, 2, 1, 0, 3, 1, 4], 0, 1);
-     * // => [2, 3, 4]
+     * _.isSafeInteger(3);
+     * // => true
+     *
+     * _.isSafeInteger(Number.MIN_VALUE);
+     * // => false
+     *
+     * _.isSafeInteger(Infinity);
+     * // => false
+     *
+     * _.isSafeInteger('3');
+     * // => false
      */
-    function without(array) {
-      return baseDifference(array, slice(arguments, 1));
+    function isSafeInteger(value) {
+      return isInteger(value) && value >= -MAX_SAFE_INTEGER && value <= MAX_SAFE_INTEGER;
     }
 
     /**
-     * Creates an array that is the symmetric difference of the provided arrays.
-     * See http://en.wikipedia.org/wiki/Symmetric_difference.
+     * Checks if `value` is classified as a `Set` object.
      *
      * @static
      * @memberOf _
-     * @category Arrays
-     * @param {...Array} [array] The arrays to inspect.
-     * @returns {Array} Returns an array of values.
+     * @since 4.3.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a set, else `false`.
      * @example
      *
-     * _.xor([1, 2, 3], [5, 2, 1, 4]);
-     * // => [3, 5, 4]
+     * _.isSet(new Set);
+     * // => true
      *
-     * _.xor([1, 2, 5], [2, 3, 5], [3, 4, 5]);
-     * // => [1, 4, 5]
+     * _.isSet(new WeakSet);
+     * // => false
      */
-    function xor() {
-      var index = -1,
-          length = arguments.length;
+    var isSet = nodeIsSet ? baseUnary(nodeIsSet) : baseIsSet;
 
-      while (++index < length) {
-        var array = arguments[index];
-        if (isArray(array) || isArguments(array)) {
-          var result = result
-            ? baseUniq(baseDifference(result, array).concat(baseDifference(array, result)))
-            : array;
-        }
-      }
-      return result || [];
+    /**
+     * Checks if `value` is classified as a `String` primitive or object.
+     *
+     * @static
+     * @since 0.1.0
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a string, else `false`.
+     * @example
+     *
+     * _.isString('abc');
+     * // => true
+     *
+     * _.isString(1);
+     * // => false
+     */
+    function isString(value) {
+      return typeof value == 'string' ||
+        (!isArray(value) && isObjectLike(value) && baseGetTag(value) == stringTag);
     }
 
     /**
-     * Creates an array of grouped elements, the first of which contains the first
-     * elements of the given arrays, the second of which contains the second
-     * elements of the given arrays, and so on.
+     * Checks if `value` is classified as a `Symbol` primitive or object.
      *
      * @static
      * @memberOf _
-     * @alias unzip
-     * @category Arrays
-     * @param {...Array} [array] Arrays to process.
-     * @returns {Array} Returns a new array of grouped elements.
+     * @since 4.0.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a symbol, else `false`.
      * @example
      *
-     * _.zip(['fred', 'barney'], [30, 40], [true, false]);
-     * // => [['fred', 30, true], ['barney', 40, false]]
+     * _.isSymbol(Symbol.iterator);
+     * // => true
+     *
+     * _.isSymbol('abc');
+     * // => false
      */
-    function zip() {
-      var array = arguments.length > 1 ? arguments : arguments[0],
-          index = -1,
-          length = array ? max(pluck(array, 'length')) : 0,
-          result = Array(length < 0 ? 0 : length);
+    function isSymbol(value) {
+      return typeof value == 'symbol' ||
+        (isObjectLike(value) && baseGetTag(value) == symbolTag);
+    }
 
-      while (++index < length) {
-        result[index] = pluck(array, index);
-      }
-      return result;
+    /**
+     * Checks if `value` is classified as a typed array.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a typed array, else `false`.
+     * @example
+     *
+     * _.isTypedArray(new Uint8Array);
+     * // => true
+     *
+     * _.isTypedArray([]);
+     * // => false
+     */
+    var isTypedArray = nodeIsTypedArray ? baseUnary(nodeIsTypedArray) : baseIsTypedArray;
+
+    /**
+     * Checks if `value` is `undefined`.
+     *
+     * @static
+     * @since 0.1.0
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is `undefined`, else `false`.
+     * @example
+     *
+     * _.isUndefined(void 0);
+     * // => true
+     *
+     * _.isUndefined(null);
+     * // => false
+     */
+    function isUndefined(value) {
+      return value === undefined;
     }
 
     /**
-     * Creates an object composed from arrays of `keys` and `values`. Provide
-     * either a single two dimensional array, i.e. `[[key1, value1], [key2, value2]]`
-     * or two arrays, one of `keys` and one of corresponding `values`.
+     * Checks if `value` is classified as a `WeakMap` object.
      *
      * @static
      * @memberOf _
-     * @alias object
-     * @category Arrays
-     * @param {Array} keys The array of keys.
-     * @param {Array} [values=[]] The array of values.
-     * @returns {Object} Returns an object composed of the given keys and
-     *  corresponding values.
+     * @since 4.3.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a weak map, else `false`.
      * @example
      *
-     * _.zipObject(['fred', 'barney'], [30, 40]);
-     * // => { 'fred': 30, 'barney': 40 }
+     * _.isWeakMap(new WeakMap);
+     * // => true
+     *
+     * _.isWeakMap(new Map);
+     * // => false
      */
-    function zipObject(keys, values) {
-      var index = -1,
-          length = keys ? keys.length : 0,
-          result = {};
+    function isWeakMap(value) {
+      return isObjectLike(value) && getTag(value) == weakMapTag;
+    }
 
-      if (!values && length && !isArray(keys[0])) {
-        values = [];
+    /**
+     * Checks if `value` is classified as a `WeakSet` object.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.3.0
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a weak set, else `false`.
+     * @example
+     *
+     * _.isWeakSet(new WeakSet);
+     * // => true
+     *
+     * _.isWeakSet(new Set);
+     * // => false
+     */
+    function isWeakSet(value) {
+      return isObjectLike(value) && baseGetTag(value) == weakSetTag;
+    }
+
+    /**
+     * Checks if `value` is less than `other`.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.9.0
+     * @category Lang
+     * @param {*} value The value to compare.
+     * @param {*} other The other value to compare.
+     * @returns {boolean} Returns `true` if `value` is less than `other`,
+     *  else `false`.
+     * @see _.gt
+     * @example
+     *
+     * _.lt(1, 3);
+     * // => true
+     *
+     * _.lt(3, 3);
+     * // => false
+     *
+     * _.lt(3, 1);
+     * // => false
+     */
+    var lt = createRelationalOperation(baseLt);
+
+    /**
+     * Checks if `value` is less than or equal to `other`.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.9.0
+     * @category Lang
+     * @param {*} value The value to compare.
+     * @param {*} other The other value to compare.
+     * @returns {boolean} Returns `true` if `value` is less than or equal to
+     *  `other`, else `false`.
+     * @see _.gte
+     * @example
+     *
+     * _.lte(1, 3);
+     * // => true
+     *
+     * _.lte(3, 3);
+     * // => true
+     *
+     * _.lte(3, 1);
+     * // => false
+     */
+    var lte = createRelationalOperation(function(value, other) {
+      return value <= other;
+    });
+
+    /**
+     * Converts `value` to an array.
+     *
+     * @static
+     * @since 0.1.0
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to convert.
+     * @returns {Array} Returns the converted array.
+     * @example
+     *
+     * _.toArray({ 'a': 1, 'b': 2 });
+     * // => [1, 2]
+     *
+     * _.toArray('abc');
+     * // => ['a', 'b', 'c']
+     *
+     * _.toArray(1);
+     * // => []
+     *
+     * _.toArray(null);
+     * // => []
+     */
+    function toArray(value) {
+      if (!value) {
+        return [];
       }
-      while (++index < length) {
-        var key = keys[index];
-        if (values) {
-          result[key] = values[index];
-        } else if (key) {
-          result[key[0]] = key[1];
-        }
+      if (isArrayLike(value)) {
+        return isString(value) ? stringToArray(value) : copyArray(value);
       }
-      return result;
-    }
+      if (symIterator && value[symIterator]) {
+        return iteratorToArray(value[symIterator]());
+      }
+      var tag = getTag(value),
+          func = tag == mapTag ? mapToArray : (tag == setTag ? setToArray : values);
 
-    /*--------------------------------------------------------------------------*/
+      return func(value);
+    }
 
     /**
-     * Creates a function that executes `func`, with  the `this` binding and
-     * arguments of the created function, only after being called `n` times.
+     * Converts `value` to a finite number.
      *
      * @static
      * @memberOf _
-     * @category Functions
-     * @param {number} n The number of times the function must be called before
-     *  `func` is executed.
-     * @param {Function} func The function to restrict.
-     * @returns {Function} Returns the new restricted function.
+     * @since 4.12.0
+     * @category Lang
+     * @param {*} value The value to convert.
+     * @returns {number} Returns the converted number.
      * @example
      *
-     * var saves = ['profile', 'settings'];
+     * _.toFinite(3.2);
+     * // => 3.2
      *
-     * var done = _.after(saves.length, function() {
-     *   console.log('Done saving!');
-     * });
+     * _.toFinite(Number.MIN_VALUE);
+     * // => 5e-324
      *
-     * _.forEach(saves, function(type) {
-     *   asyncSave({ 'type': type, 'complete': done });
-     * });
-     * // => logs 'Done saving!', after all saves have completed
+     * _.toFinite(Infinity);
+     * // => 1.7976931348623157e+308
+     *
+     * _.toFinite('3.2');
+     * // => 3.2
      */
-    function after(n, func) {
-      if (!isFunction(func)) {
-        throw new TypeError;
+    function toFinite(value) {
+      if (!value) {
+        return value === 0 ? value : 0;
       }
-      return function() {
-        if (--n < 1) {
-          return func.apply(this, arguments);
-        }
-      };
+      value = toNumber(value);
+      if (value === INFINITY || value === -INFINITY) {
+        var sign = (value < 0 ? -1 : 1);
+        return sign * MAX_INTEGER;
+      }
+      return value === value ? value : 0;
     }
 
     /**
-     * Creates a function that, when called, invokes `func` with the `this`
-     * binding of `thisArg` and prepends any additional `bind` arguments to those
-     * provided to the bound function.
+     * Converts `value` to an integer.
+     *
+     * **Note:** This method is loosely based on
+     * [`ToInteger`](http://www.ecma-international.org/ecma-262/7.0/#sec-tointeger).
      *
      * @static
      * @memberOf _
-     * @category Functions
-     * @param {Function} func The function to bind.
-     * @param {*} [thisArg] The `this` binding of `func`.
-     * @param {...*} [arg] Arguments to be partially applied.
-     * @returns {Function} Returns the new bound function.
+     * @since 4.0.0
+     * @category Lang
+     * @param {*} value The value to convert.
+     * @returns {number} Returns the converted integer.
      * @example
      *
-     * var func = function(greeting) {
-     *   return greeting + ' ' + this.name;
-     * };
+     * _.toInteger(3.2);
+     * // => 3
      *
-     * func = _.bind(func, { 'name': 'fred' }, 'hi');
-     * func();
-     * // => 'hi fred'
+     * _.toInteger(Number.MIN_VALUE);
+     * // => 0
+     *
+     * _.toInteger(Infinity);
+     * // => 1.7976931348623157e+308
+     *
+     * _.toInteger('3.2');
+     * // => 3
      */
-    function bind(func, thisArg) {
-      return arguments.length > 2
-        ? createWrapper(func, 17, slice(arguments, 2), null, thisArg)
-        : createWrapper(func, 1, null, null, thisArg);
+    function toInteger(value) {
+      var result = toFinite(value),
+          remainder = result % 1;
+
+      return result === result ? (remainder ? result - remainder : result) : 0;
     }
 
     /**
-     * Binds methods of an object to the object itself, overwriting the existing
-     * method. Method names may be specified as individual arguments or as arrays
-     * of method names. If no method names are provided all the function properties
-     * of `object` will be bound.
+     * Converts `value` to an integer suitable for use as the length of an
+     * array-like object.
+     *
+     * **Note:** This method is based on
+     * [`ToLength`](http://ecma-international.org/ecma-262/7.0/#sec-tolength).
      *
      * @static
      * @memberOf _
-     * @category Functions
-     * @param {Object} object The object to bind and assign the bound methods to.
-     * @param {...string} [methodName] The object method names to
-     *  bind, specified as individual method names or arrays of method names.
-     * @returns {Object} Returns `object`.
+     * @since 4.0.0
+     * @category Lang
+     * @param {*} value The value to convert.
+     * @returns {number} Returns the converted integer.
      * @example
      *
-     * var view = {
-     *   'label': 'docs',
-     *   'onClick': function() { console.log('clicked ' + this.label); }
-     * };
+     * _.toLength(3.2);
+     * // => 3
+     *
+     * _.toLength(Number.MIN_VALUE);
+     * // => 0
      *
-     * _.bindAll(view);
-     * jQuery('#docs').on('click', view.onClick);
-     * // => logs 'clicked docs', when the button is clicked
+     * _.toLength(Infinity);
+     * // => 4294967295
+     *
+     * _.toLength('3.2');
+     * // => 3
      */
-    function bindAll(object) {
-      var funcs = arguments.length > 1 ? baseFlatten(arguments, true, false, 1) : functions(object),
-          index = -1,
-          length = funcs.length;
+    function toLength(value) {
+      return value ? baseClamp(toInteger(value), 0, MAX_ARRAY_LENGTH) : 0;
+    }
 
-      while (++index < length) {
-        var key = funcs[index];
-        object[key] = createWrapper(object[key], 1, null, null, object);
+    /**
+     * Converts `value` to a number.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Lang
+     * @param {*} value The value to process.
+     * @returns {number} Returns the number.
+     * @example
+     *
+     * _.toNumber(3.2);
+     * // => 3.2
+     *
+     * _.toNumber(Number.MIN_VALUE);
+     * // => 5e-324
+     *
+     * _.toNumber(Infinity);
+     * // => Infinity
+     *
+     * _.toNumber('3.2');
+     * // => 3.2
+     */
+    function toNumber(value) {
+      if (typeof value == 'number') {
+        return value;
       }
-      return object;
+      if (isSymbol(value)) {
+        return NAN;
+      }
+      if (isObject(value)) {
+        var other = typeof value.valueOf == 'function' ? value.valueOf() : value;
+        value = isObject(other) ? (other + '') : other;
+      }
+      if (typeof value != 'string') {
+        return value === 0 ? value : +value;
+      }
+      value = baseTrim(value);
+      var isBinary = reIsBinary.test(value);
+      return (isBinary || reIsOctal.test(value))
+        ? freeParseInt(value.slice(2), isBinary ? 2 : 8)
+        : (reIsBadHex.test(value) ? NAN : +value);
     }
 
     /**
-     * Creates a function that, when called, invokes the method at `object[key]`
-     * and prepends any additional `bindKey` arguments to those provided to the bound
-     * function. This method differs from `_.bind` by allowing bound functions to
-     * reference methods that will be redefined or don't yet exist.
-     * See http://michaux.ca/articles/lazy-function-definition-pattern.
+     * Converts `value` to a plain object flattening inherited enumerable string
+     * keyed properties of `value` to own properties of the plain object.
      *
      * @static
      * @memberOf _
-     * @category Functions
-     * @param {Object} object The object the method belongs to.
-     * @param {string} key The key of the method.
-     * @param {...*} [arg] Arguments to be partially applied.
-     * @returns {Function} Returns the new bound function.
+     * @since 3.0.0
+     * @category Lang
+     * @param {*} value The value to convert.
+     * @returns {Object} Returns the converted plain object.
      * @example
      *
-     * var object = {
-     *   'name': 'fred',
-     *   'greet': function(greeting) {
-     *     return greeting + ' ' + this.name;
-     *   }
-     * };
+     * function Foo() {
+     *   this.b = 2;
+     * }
      *
-     * var func = _.bindKey(object, 'greet', 'hi');
-     * func();
-     * // => 'hi fred'
+     * Foo.prototype.c = 3;
      *
-     * object.greet = function(greeting) {
-     *   return greeting + 'ya ' + this.name + '!';
-     * };
+     * _.assign({ 'a': 1 }, new Foo);
+     * // => { 'a': 1, 'b': 2 }
      *
-     * func();
-     * // => 'hiya fred!'
+     * _.assign({ 'a': 1 }, _.toPlainObject(new Foo));
+     * // => { 'a': 1, 'b': 2, 'c': 3 }
      */
-    function bindKey(object, key) {
-      return arguments.length > 2
-        ? createWrapper(key, 19, slice(arguments, 2), null, object)
-        : createWrapper(key, 3, null, null, object);
+    function toPlainObject(value) {
+      return copyObject(value, keysIn(value));
     }
 
     /**
-     * Creates a function that is the composition of the provided functions,
-     * where each function consumes the return value of the function that follows.
-     * For example, composing the functions `f()`, `g()`, and `h()` produces `f(g(h()))`.
-     * Each function is executed with the `this` binding of the composed function.
+     * Converts `value` to a safe integer. A safe integer can be compared and
+     * represented correctly.
      *
      * @static
      * @memberOf _
-     * @category Functions
-     * @param {...Function} [func] Functions to compose.
-     * @returns {Function} Returns the new composed function.
+     * @since 4.0.0
+     * @category Lang
+     * @param {*} value The value to convert.
+     * @returns {number} Returns the converted integer.
      * @example
      *
-     * var realNameMap = {
-     *   'pebbles': 'penelope'
-     * };
+     * _.toSafeInteger(3.2);
+     * // => 3
      *
-     * var format = function(name) {
-     *   name = realNameMap[name.toLowerCase()] || name;
-     *   return name.charAt(0).toUpperCase() + name.slice(1).toLowerCase();
-     * };
+     * _.toSafeInteger(Number.MIN_VALUE);
+     * // => 0
      *
-     * var greet = function(formatted) {
-     *   return 'Hiya ' + formatted + '!';
-     * };
+     * _.toSafeInteger(Infinity);
+     * // => 9007199254740991
      *
-     * var welcome = _.compose(greet, format);
-     * welcome('pebbles');
-     * // => 'Hiya Penelope!'
-     */
-    function compose() {
-      var funcs = arguments,
-          length = funcs.length;
+     * _.toSafeInteger('3.2');
+     * // => 3
+     */
+    function toSafeInteger(value) {
+      return value
+        ? baseClamp(toInteger(value), -MAX_SAFE_INTEGER, MAX_SAFE_INTEGER)
+        : (value === 0 ? value : 0);
+    }
 
-      while (length--) {
-        if (!isFunction(funcs[length])) {
-          throw new TypeError;
+    /**
+     * Converts `value` to a string. An empty string is returned for `null`
+     * and `undefined` values. The sign of `-0` is preserved.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Lang
+     * @param {*} value The value to convert.
+     * @returns {string} Returns the converted string.
+     * @example
+     *
+     * _.toString(null);
+     * // => ''
+     *
+     * _.toString(-0);
+     * // => '-0'
+     *
+     * _.toString([1, 2, 3]);
+     * // => '1,2,3'
+     */
+    function toString(value) {
+      return value == null ? '' : baseToString(value);
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Assigns own enumerable string keyed properties of source objects to the
+     * destination object. Source objects are applied from left to right.
+     * Subsequent sources overwrite property assignments of previous sources.
+     *
+     * **Note:** This method mutates `object` and is loosely based on
+     * [`Object.assign`](https://mdn.io/Object/assign).
+     *
+     * @static
+     * @memberOf _
+     * @since 0.10.0
+     * @category Object
+     * @param {Object} object The destination object.
+     * @param {...Object} [sources] The source objects.
+     * @returns {Object} Returns `object`.
+     * @see _.assignIn
+     * @example
+     *
+     * function Foo() {
+     *   this.a = 1;
+     * }
+     *
+     * function Bar() {
+     *   this.c = 3;
+     * }
+     *
+     * Foo.prototype.b = 2;
+     * Bar.prototype.d = 4;
+     *
+     * _.assign({ 'a': 0 }, new Foo, new Bar);
+     * // => { 'a': 1, 'c': 3 }
+     */
+    var assign = createAssigner(function(object, source) {
+      if (isPrototype(source) || isArrayLike(source)) {
+        copyObject(source, keys(source), object);
+        return;
+      }
+      for (var key in source) {
+        if (hasOwnProperty.call(source, key)) {
+          assignValue(object, key, source[key]);
         }
       }
-      return function() {
-        var args = arguments,
-            length = funcs.length;
+    });
 
-        while (length--) {
-          args = [funcs[length].apply(this, args)];
-        }
-        return args[0];
-      };
-    }
+    /**
+     * This method is like `_.assign` except that it iterates over own and
+     * inherited source properties.
+     *
+     * **Note:** This method mutates `object`.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @alias extend
+     * @category Object
+     * @param {Object} object The destination object.
+     * @param {...Object} [sources] The source objects.
+     * @returns {Object} Returns `object`.
+     * @see _.assign
+     * @example
+     *
+     * function Foo() {
+     *   this.a = 1;
+     * }
+     *
+     * function Bar() {
+     *   this.c = 3;
+     * }
+     *
+     * Foo.prototype.b = 2;
+     * Bar.prototype.d = 4;
+     *
+     * _.assignIn({ 'a': 0 }, new Foo, new Bar);
+     * // => { 'a': 1, 'b': 2, 'c': 3, 'd': 4 }
+     */
+    var assignIn = createAssigner(function(object, source) {
+      copyObject(source, keysIn(source), object);
+    });
 
     /**
-     * Creates a function which accepts one or more arguments of `func` that when
-     * invoked either executes `func` returning its result, if all `func` arguments
-     * have been provided, or returns a function that accepts one or more of the
-     * remaining `func` arguments, and so on. The arity of `func` can be specified
-     * if `func.length` is not sufficient.
+     * This method is like `_.assignIn` except that it accepts `customizer`
+     * which is invoked to produce the assigned values. If `customizer` returns
+     * `undefined`, assignment is handled by the method instead. The `customizer`
+     * is invoked with five arguments: (objValue, srcValue, key, object, source).
+     *
+     * **Note:** This method mutates `object`.
      *
      * @static
      * @memberOf _
-     * @category Functions
-     * @param {Function} func The function to curry.
-     * @param {number} [arity=func.length] The arity of `func`.
-     * @returns {Function} Returns the new curried function.
+     * @since 4.0.0
+     * @alias extendWith
+     * @category Object
+     * @param {Object} object The destination object.
+     * @param {...Object} sources The source objects.
+     * @param {Function} [customizer] The function to customize assigned values.
+     * @returns {Object} Returns `object`.
+     * @see _.assignWith
      * @example
      *
-     * var curried = _.curry(function(a, b, c) {
-     *   console.log(a + b + c);
-     * });
+     * function customizer(objValue, srcValue) {
+     *   return _.isUndefined(objValue) ? srcValue : objValue;
+     * }
      *
-     * curried(1)(2)(3);
-     * // => 6
+     * var defaults = _.partialRight(_.assignInWith, customizer);
      *
-     * curried(1, 2)(3);
-     * // => 6
+     * defaults({ 'a': 1 }, { 'b': 2 }, { 'a': 3 });
+     * // => { 'a': 1, 'b': 2 }
+     */
+    var assignInWith = createAssigner(function(object, source, srcIndex, customizer) {
+      copyObject(source, keysIn(source), object, customizer);
+    });
+
+    /**
+     * This method is like `_.assign` except that it accepts `customizer`
+     * which is invoked to produce the assigned values. If `customizer` returns
+     * `undefined`, assignment is handled by the method instead. The `customizer`
+     * is invoked with five arguments: (objValue, srcValue, key, object, source).
      *
-     * curried(1, 2, 3);
-     * // => 6
+     * **Note:** This method mutates `object`.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Object
+     * @param {Object} object The destination object.
+     * @param {...Object} sources The source objects.
+     * @param {Function} [customizer] The function to customize assigned values.
+     * @returns {Object} Returns `object`.
+     * @see _.assignInWith
+     * @example
+     *
+     * function customizer(objValue, srcValue) {
+     *   return _.isUndefined(objValue) ? srcValue : objValue;
+     * }
+     *
+     * var defaults = _.partialRight(_.assignWith, customizer);
+     *
+     * defaults({ 'a': 1 }, { 'b': 2 }, { 'a': 3 });
+     * // => { 'a': 1, 'b': 2 }
      */
-    function curry(func, arity) {
-      arity = typeof arity == 'number' ? arity : (+arity || func.length);
-      return createWrapper(func, 4, null, null, null, arity);
-    }
+    var assignWith = createAssigner(function(object, source, srcIndex, customizer) {
+      copyObject(source, keys(source), object, customizer);
+    });
 
     /**
-     * Creates a function that will delay the execution of `func` until after
-     * `wait` milliseconds have elapsed since the last time it was invoked.
-     * Provide an options object to indicate that `func` should be invoked on
-     * the leading and/or trailing edge of the `wait` timeout. Subsequent calls
-     * to the debounced function will return the result of the last `func` call.
+     * Creates an array of values corresponding to `paths` of `object`.
+     *
+     * @static
+     * @memberOf _
+     * @since 1.0.0
+     * @category Object
+     * @param {Object} object The object to iterate over.
+     * @param {...(string|string[])} [paths] The property paths to pick.
+     * @returns {Array} Returns the picked values.
+     * @example
      *
-     * Note: If `leading` and `trailing` options are `true` `func` will be called
-     * on the trailing edge of the timeout only if the the debounced function is
-     * invoked more than once during the `wait` timeout.
+     * var object = { 'a': [{ 'b': { 'c': 3 } }, 4] };
+     *
+     * _.at(object, ['a[0].b.c', 'a[1]']);
+     * // => [3, 4]
+     */
+    var at = flatRest(baseAt);
+
+    /**
+     * Creates an object that inherits from the `prototype` object. If a
+     * `properties` object is given, its own enumerable string keyed properties
+     * are assigned to the created object.
      *
      * @static
      * @memberOf _
-     * @category Functions
-     * @param {Function} func The function to debounce.
-     * @param {number} wait The number of milliseconds to delay.
-     * @param {Object} [options] The options object.
-     * @param {boolean} [options.leading=false] Specify execution on the leading edge of the timeout.
-     * @param {number} [options.maxWait] The maximum time `func` is allowed to be delayed before it's called.
-     * @param {boolean} [options.trailing=true] Specify execution on the trailing edge of the timeout.
-     * @returns {Function} Returns the new debounced function.
+     * @since 2.3.0
+     * @category Object
+     * @param {Object} prototype The object to inherit from.
+     * @param {Object} [properties] The properties to assign to the object.
+     * @returns {Object} Returns the new object.
      * @example
      *
-     * // avoid costly calculations while the window size is in flux
-     * var lazyLayout = _.debounce(calculateLayout, 150);
-     * jQuery(window).on('resize', lazyLayout);
+     * function Shape() {
+     *   this.x = 0;
+     *   this.y = 0;
+     * }
      *
-     * // execute `sendMail` when the click event is fired, debouncing subsequent calls
-     * jQuery('#postbox').on('click', _.debounce(sendMail, 300, {
-     *   'leading': true,
-     *   'trailing': false
+     * function Circle() {
+     *   Shape.call(this);
+     * }
+     *
+     * Circle.prototype = _.create(Shape.prototype, {
+     *   'constructor': Circle
      * });
      *
-     * // ensure `batchLog` is executed once after 1 second of debounced calls
-     * var source = new EventSource('/stream');
-     * source.addEventListener('message', _.debounce(batchLog, 250, {
-     *   'maxWait': 1000
-     * }, false);
+     * var circle = new Circle;
+     * circle instanceof Circle;
+     * // => true
+     *
+     * circle instanceof Shape;
+     * // => true
      */
-    function debounce(func, wait, options) {
-      var args,
-          maxTimeoutId,
-          result,
-          stamp,
-          thisArg,
-          timeoutId,
-          trailingCall,
-          lastCalled = 0,
-          maxWait = false,
-          trailing = true;
+    function create(prototype, properties) {
+      var result = baseCreate(prototype);
+      return properties == null ? result : baseAssign(result, properties);
+    }
+
+    /**
+     * Assigns own and inherited enumerable string keyed properties of source
+     * objects to the destination object for all destination properties that
+     * resolve to `undefined`. Source objects are applied from left to right.
+     * Once a property is set, additional values of the same property are ignored.
+     *
+     * **Note:** This method mutates `object`.
+     *
+     * @static
+     * @since 0.1.0
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The destination object.
+     * @param {...Object} [sources] The source objects.
+     * @returns {Object} Returns `object`.
+     * @see _.defaultsDeep
+     * @example
+     *
+     * _.defaults({ 'a': 1 }, { 'b': 2 }, { 'a': 3 });
+     * // => { 'a': 1, 'b': 2 }
+     */
+    var defaults = baseRest(function(object, sources) {
+      object = Object(object);
+
+      var index = -1;
+      var length = sources.length;
+      var guard = length > 2 ? sources[2] : undefined;
 
-      if (!isFunction(func)) {
-        throw new TypeError;
+      if (guard && isIterateeCall(sources[0], sources[1], guard)) {
+        length = 1;
       }
-      wait = nativeMax(0, wait) || 0;
-      if (options === true) {
-        var leading = true;
-        trailing = false;
-      } else if (isObject(options)) {
-        leading = options.leading;
-        maxWait = 'maxWait' in options && (nativeMax(wait, options.maxWait) || 0);
-        trailing = 'trailing' in options ? options.trailing : trailing;
-      }
-      var delayed = function() {
-        var remaining = wait - (now() - stamp);
-        if (remaining <= 0) {
-          if (maxTimeoutId) {
-            clearTimeout(maxTimeoutId);
-          }
-          var isCalled = trailingCall;
-          maxTimeoutId = timeoutId = trailingCall = undefined;
-          if (isCalled) {
-            lastCalled = now();
-            result = func.apply(thisArg, args);
-            if (!timeoutId && !maxTimeoutId) {
-              args = thisArg = null;
-            }
-          }
-        } else {
-          timeoutId = setTimeout(delayed, remaining);
-        }
-      };
 
-      var maxDelayed = function() {
-        if (timeoutId) {
-          clearTimeout(timeoutId);
-        }
-        maxTimeoutId = timeoutId = trailingCall = undefined;
-        if (trailing || (maxWait !== wait)) {
-          lastCalled = now();
-          result = func.apply(thisArg, args);
-          if (!timeoutId && !maxTimeoutId) {
-            args = thisArg = null;
+      while (++index < length) {
+        var source = sources[index];
+        var props = keysIn(source);
+        var propsIndex = -1;
+        var propsLength = props.length;
+
+        while (++propsIndex < propsLength) {
+          var key = props[propsIndex];
+          var value = object[key];
+
+          if (value === undefined ||
+              (eq(value, objectProto[key]) && !hasOwnProperty.call(object, key))) {
+            object[key] = source[key];
           }
         }
-      };
+      }
 
-      return function() {
-        args = arguments;
-        stamp = now();
-        thisArg = this;
-        trailingCall = trailing && (timeoutId || !leading);
+      return object;
+    });
 
-        if (maxWait === false) {
-          var leadingCall = leading && !timeoutId;
-        } else {
-          if (!maxTimeoutId && !leading) {
-            lastCalled = stamp;
-          }
-          var remaining = maxWait - (stamp - lastCalled),
-              isCalled = remaining <= 0;
+    /**
+     * This method is like `_.defaults` except that it recursively assigns
+     * default properties.
+     *
+     * **Note:** This method mutates `object`.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.10.0
+     * @category Object
+     * @param {Object} object The destination object.
+     * @param {...Object} [sources] The source objects.
+     * @returns {Object} Returns `object`.
+     * @see _.defaults
+     * @example
+     *
+     * _.defaultsDeep({ 'a': { 'b': 2 } }, { 'a': { 'b': 1, 'c': 3 } });
+     * // => { 'a': { 'b': 2, 'c': 3 } }
+     */
+    var defaultsDeep = baseRest(function(args) {
+      args.push(undefined, customDefaultsMerge);
+      return apply(mergeWith, undefined, args);
+    });
 
-          if (isCalled) {
-            if (maxTimeoutId) {
-              maxTimeoutId = clearTimeout(maxTimeoutId);
-            }
-            lastCalled = stamp;
-            result = func.apply(thisArg, args);
-          }
-          else if (!maxTimeoutId) {
-            maxTimeoutId = setTimeout(maxDelayed, remaining);
-          }
-        }
-        if (isCalled && timeoutId) {
-          timeoutId = clearTimeout(timeoutId);
-        }
-        else if (!timeoutId && wait !== maxWait) {
-          timeoutId = setTimeout(delayed, wait);
-        }
-        if (leadingCall) {
-          isCalled = true;
-          result = func.apply(thisArg, args);
-        }
-        if (isCalled && !timeoutId && !maxTimeoutId) {
-          args = thisArg = null;
-        }
-        return result;
-      };
+    /**
+     * This method is like `_.find` except that it returns the key of the first
+     * element `predicate` returns truthy for instead of the element itself.
+     *
+     * @static
+     * @memberOf _
+     * @since 1.1.0
+     * @category Object
+     * @param {Object} object The object to inspect.
+     * @param {Function} [predicate=_.identity] The function invoked per iteration.
+     * @returns {string|undefined} Returns the key of the matched element,
+     *  else `undefined`.
+     * @example
+     *
+     * var users = {
+     *   'barney':  { 'age': 36, 'active': true },
+     *   'fred':    { 'age': 40, 'active': false },
+     *   'pebbles': { 'age': 1,  'active': true }
+     * };
+     *
+     * _.findKey(users, function(o) { return o.age < 40; });
+     * // => 'barney' (iteration order is not guaranteed)
+     *
+     * // The `_.matches` iteratee shorthand.
+     * _.findKey(users, { 'age': 1, 'active': true });
+     * // => 'pebbles'
+     *
+     * // The `_.matchesProperty` iteratee shorthand.
+     * _.findKey(users, ['active', false]);
+     * // => 'fred'
+     *
+     * // The `_.property` iteratee shorthand.
+     * _.findKey(users, 'active');
+     * // => 'barney'
+     */
+    function findKey(object, predicate) {
+      return baseFindKey(object, getIteratee(predicate, 3), baseForOwn);
     }
 
     /**
-     * Defers executing the `func` function until the current call stack has cleared.
-     * Additional arguments will be provided to `func` when it is invoked.
+     * This method is like `_.findKey` except that it iterates over elements of
+     * a collection in the opposite order.
      *
      * @static
      * @memberOf _
-     * @category Functions
-     * @param {Function} func The function to defer.
-     * @param {...*} [arg] Arguments to invoke the function with.
-     * @returns {number} Returns the timer id.
+     * @since 2.0.0
+     * @category Object
+     * @param {Object} object The object to inspect.
+     * @param {Function} [predicate=_.identity] The function invoked per iteration.
+     * @returns {string|undefined} Returns the key of the matched element,
+     *  else `undefined`.
      * @example
      *
-     * _.defer(function(text) { console.log(text); }, 'deferred');
-     * // logs 'deferred' after one or more milliseconds
+     * var users = {
+     *   'barney':  { 'age': 36, 'active': true },
+     *   'fred':    { 'age': 40, 'active': false },
+     *   'pebbles': { 'age': 1,  'active': true }
+     * };
+     *
+     * _.findLastKey(users, function(o) { return o.age < 40; });
+     * // => returns 'pebbles' assuming `_.findKey` returns 'barney'
+     *
+     * // The `_.matches` iteratee shorthand.
+     * _.findLastKey(users, { 'age': 36, 'active': true });
+     * // => 'barney'
+     *
+     * // The `_.matchesProperty` iteratee shorthand.
+     * _.findLastKey(users, ['active', false]);
+     * // => 'fred'
+     *
+     * // The `_.property` iteratee shorthand.
+     * _.findLastKey(users, 'active');
+     * // => 'pebbles'
      */
-    function defer(func) {
-      if (!isFunction(func)) {
-        throw new TypeError;
-      }
-      var args = slice(arguments, 1);
-      return setTimeout(function() { func.apply(undefined, args); }, 1);
+    function findLastKey(object, predicate) {
+      return baseFindKey(object, getIteratee(predicate, 3), baseForOwnRight);
     }
 
     /**
-     * Executes the `func` function after `wait` milliseconds. Additional arguments
-     * will be provided to `func` when it is invoked.
+     * Iterates over own and inherited enumerable string keyed properties of an
+     * object and invokes `iteratee` for each property. The iteratee is invoked
+     * with three arguments: (value, key, object). Iteratee functions may exit
+     * iteration early by explicitly returning `false`.
      *
      * @static
      * @memberOf _
-     * @category Functions
-     * @param {Function} func The function to delay.
-     * @param {number} wait The number of milliseconds to delay execution.
-     * @param {...*} [arg] Arguments to invoke the function with.
-     * @returns {number} Returns the timer id.
+     * @since 0.3.0
+     * @category Object
+     * @param {Object} object The object to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @returns {Object} Returns `object`.
+     * @see _.forInRight
      * @example
      *
-     * _.delay(function(text) { console.log(text); }, 1000, 'later');
-     * // => logs 'later' after one second
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
+     *
+     * _.forIn(new Foo, function(value, key) {
+     *   console.log(key);
+     * });
+     * // => Logs 'a', 'b', then 'c' (iteration order is not guaranteed).
      */
-    function delay(func, wait) {
-      if (!isFunction(func)) {
-        throw new TypeError;
-      }
-      var args = slice(arguments, 2);
-      return setTimeout(function() { func.apply(undefined, args); }, wait);
+    function forIn(object, iteratee) {
+      return object == null
+        ? object
+        : baseFor(object, getIteratee(iteratee, 3), keysIn);
     }
 
     /**
-     * Creates a function that memoizes the result of `func`. If `resolver` is
-     * provided it will be used to determine the cache key for storing the result
-     * based on the arguments provided to the memoized function. By default, the
-     * first argument provided to the memoized function is used as the cache key.
-     * The `func` is executed with the `this` binding of the memoized function.
-     * The result cache is exposed as the `cache` property on the memoized function.
+     * This method is like `_.forIn` except that it iterates over properties of
+     * `object` in the opposite order.
      *
      * @static
      * @memberOf _
-     * @category Functions
-     * @param {Function} func The function to have its output memoized.
-     * @param {Function} [resolver] A function used to resolve the cache key.
-     * @returns {Function} Returns the new memoizing function.
+     * @since 2.0.0
+     * @category Object
+     * @param {Object} object The object to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @returns {Object} Returns `object`.
+     * @see _.forIn
      * @example
      *
-     * var fibonacci = _.memoize(function(n) {
-     *   return n < 2 ? n : fibonacci(n - 1) + fibonacci(n - 2);
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
+     *
+     * _.forInRight(new Foo, function(value, key) {
+     *   console.log(key);
      * });
+     * // => Logs 'c', 'b', then 'a' assuming `_.forIn` logs 'a', 'b', then 'c'.
+     */
+    function forInRight(object, iteratee) {
+      return object == null
+        ? object
+        : baseForRight(object, getIteratee(iteratee, 3), keysIn);
+    }
+
+    /**
+     * Iterates over own enumerable string keyed properties of an object and
+     * invokes `iteratee` for each property. The iteratee is invoked with three
+     * arguments: (value, key, object). Iteratee functions may exit iteration
+     * early by explicitly returning `false`.
      *
-     * fibonacci(9)
-     * // => 34
+     * @static
+     * @memberOf _
+     * @since 0.3.0
+     * @category Object
+     * @param {Object} object The object to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @returns {Object} Returns `object`.
+     * @see _.forOwnRight
+     * @example
      *
-     * var data = {
-     *   'fred': { 'name': 'fred', 'age': 40 },
-     *   'pebbles': { 'name': 'pebbles', 'age': 1 }
-     * };
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
      *
-     * // modifying the result cache
-     * var get = _.memoize(function(name) { return data[name]; }, _.identity);
-     * get('pebbles');
-     * // => { 'name': 'pebbles', 'age': 1 }
-     *
-     * get.cache.pebbles.name = 'penelope';
-     * get('pebbles');
-     * // => { 'name': 'penelope', 'age': 1 }
+     * _.forOwn(new Foo, function(value, key) {
+     *   console.log(key);
+     * });
+     * // => Logs 'a' then 'b' (iteration order is not guaranteed).
      */
-    function memoize(func, resolver) {
-      if (!isFunction(func)) {
-        throw new TypeError;
-      }
-      var memoized = function() {
-        var cache = memoized.cache,
-            key = resolver ? resolver.apply(this, arguments) : keyPrefix + arguments[0];
-
-        return hasOwnProperty.call(cache, key)
-          ? cache[key]
-          : (cache[key] = func.apply(this, arguments));
-      }
-      memoized.cache = {};
-      return memoized;
+    function forOwn(object, iteratee) {
+      return object && baseForOwn(object, getIteratee(iteratee, 3));
     }
 
     /**
-     * Creates a function that is restricted to execute `func` once. Repeat calls to
-     * the function will return the value of the first call. The `func` is executed
-     * with the `this` binding of the created function.
+     * This method is like `_.forOwn` except that it iterates over properties of
+     * `object` in the opposite order.
      *
      * @static
      * @memberOf _
-     * @category Functions
-     * @param {Function} func The function to restrict.
-     * @returns {Function} Returns the new restricted function.
+     * @since 2.0.0
+     * @category Object
+     * @param {Object} object The object to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @returns {Object} Returns `object`.
+     * @see _.forOwn
      * @example
      *
-     * var initialize = _.once(createApplication);
-     * initialize();
-     * initialize();
-     * // `initialize` executes `createApplication` once
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
+     *
+     * _.forOwnRight(new Foo, function(value, key) {
+     *   console.log(key);
+     * });
+     * // => Logs 'b' then 'a' assuming `_.forOwn` logs 'a' then 'b'.
      */
-    function once(func) {
-      var ran,
-          result;
+    function forOwnRight(object, iteratee) {
+      return object && baseForOwnRight(object, getIteratee(iteratee, 3));
+    }
 
-      if (!isFunction(func)) {
-        throw new TypeError;
-      }
-      return function() {
-        if (ran) {
-          return result;
-        }
-        ran = true;
-        result = func.apply(this, arguments);
+    /**
+     * Creates an array of function property names from own enumerable properties
+     * of `object`.
+     *
+     * @static
+     * @since 0.1.0
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to inspect.
+     * @returns {Array} Returns the function names.
+     * @see _.functionsIn
+     * @example
+     *
+     * function Foo() {
+     *   this.a = _.constant('a');
+     *   this.b = _.constant('b');
+     * }
+     *
+     * Foo.prototype.c = _.constant('c');
+     *
+     * _.functions(new Foo);
+     * // => ['a', 'b']
+     */
+    function functions(object) {
+      return object == null ? [] : baseFunctions(object, keys(object));
+    }
 
-        // clear the `func` variable so the function may be garbage collected
-        func = null;
-        return result;
-      };
+    /**
+     * Creates an array of function property names from own and inherited
+     * enumerable properties of `object`.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Object
+     * @param {Object} object The object to inspect.
+     * @returns {Array} Returns the function names.
+     * @see _.functions
+     * @example
+     *
+     * function Foo() {
+     *   this.a = _.constant('a');
+     *   this.b = _.constant('b');
+     * }
+     *
+     * Foo.prototype.c = _.constant('c');
+     *
+     * _.functionsIn(new Foo);
+     * // => ['a', 'b', 'c']
+     */
+    function functionsIn(object) {
+      return object == null ? [] : baseFunctions(object, keysIn(object));
     }
 
     /**
-     * Creates a function that, when called, invokes `func` with any additional
-     * `partial` arguments prepended to those provided to the new function. This
-     * method is similar to `_.bind` except it does **not** alter the `this` binding.
+     * Gets the value at `path` of `object`. If the resolved value is
+     * `undefined`, the `defaultValue` is returned in its place.
      *
      * @static
      * @memberOf _
-     * @category Functions
-     * @param {Function} func The function to partially apply arguments to.
-     * @param {...*} [arg] Arguments to be partially applied.
-     * @returns {Function} Returns the new partially applied function.
+     * @since 3.7.0
+     * @category Object
+     * @param {Object} object The object to query.
+     * @param {Array|string} path The path of the property to get.
+     * @param {*} [defaultValue] The value returned for `undefined` resolved values.
+     * @returns {*} Returns the resolved value.
      * @example
      *
-     * var greet = function(greeting, name) { return greeting + ' ' + name; };
-     * var hi = _.partial(greet, 'hi');
-     * hi('fred');
-     * // => 'hi fred'
+     * var object = { 'a': [{ 'b': { 'c': 3 } }] };
+     *
+     * _.get(object, 'a[0].b.c');
+     * // => 3
+     *
+     * _.get(object, ['a', '0', 'b', 'c']);
+     * // => 3
+     *
+     * _.get(object, 'a.b.c', 'default');
+     * // => 'default'
      */
-    function partial(func) {
-      return createWrapper(func, 16, slice(arguments, 1));
+    function get(object, path, defaultValue) {
+      var result = object == null ? undefined : baseGet(object, path);
+      return result === undefined ? defaultValue : result;
     }
 
     /**
-     * This method is like `_.partial` except that `partial` arguments are
-     * appended to those provided to the new function.
+     * Checks if `path` is a direct property of `object`.
      *
      * @static
+     * @since 0.1.0
      * @memberOf _
-     * @category Functions
-     * @param {Function} func The function to partially apply arguments to.
-     * @param {...*} [arg] Arguments to be partially applied.
-     * @returns {Function} Returns the new partially applied function.
+     * @category Object
+     * @param {Object} object The object to query.
+     * @param {Array|string} path The path to check.
+     * @returns {boolean} Returns `true` if `path` exists, else `false`.
      * @example
      *
-     * var defaultsDeep = _.partialRight(_.merge, _.defaults);
+     * var object = { 'a': { 'b': 2 } };
+     * var other = _.create({ 'a': _.create({ 'b': 2 }) });
      *
-     * var options = {
-     *   'variable': 'data',
-     *   'imports': { 'jq': $ }
-     * };
+     * _.has(object, 'a');
+     * // => true
      *
-     * defaultsDeep(options, _.templateSettings);
+     * _.has(object, 'a.b');
+     * // => true
      *
-     * options.variable
-     * // => 'data'
+     * _.has(object, ['a', 'b']);
+     * // => true
      *
-     * options.imports
-     * // => { '_': _, 'jq': $ }
+     * _.has(other, 'a');
+     * // => false
      */
-    function partialRight(func) {
-      return createWrapper(func, 32, null, slice(arguments, 1));
+    function has(object, path) {
+      return object != null && hasPath(object, path, baseHas);
     }
 
     /**
-     * Creates a function that, when executed, will only call the `func` function
-     * at most once per every `wait` milliseconds. Provide an options object to
-     * indicate that `func` should be invoked on the leading and/or trailing edge
-     * of the `wait` timeout. Subsequent calls to the throttled function will
-     * return the result of the last `func` call.
+     * Checks if `path` is a direct or inherited property of `object`.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Object
+     * @param {Object} object The object to query.
+     * @param {Array|string} path The path to check.
+     * @returns {boolean} Returns `true` if `path` exists, else `false`.
+     * @example
+     *
+     * var object = _.create({ 'a': _.create({ 'b': 2 }) });
      *
-     * Note: If `leading` and `trailing` options are `true` `func` will be called
-     * on the trailing edge of the timeout only if the the throttled function is
-     * invoked more than once during the `wait` timeout.
+     * _.hasIn(object, 'a');
+     * // => true
+     *
+     * _.hasIn(object, 'a.b');
+     * // => true
+     *
+     * _.hasIn(object, ['a', 'b']);
+     * // => true
+     *
+     * _.hasIn(object, 'b');
+     * // => false
+     */
+    function hasIn(object, path) {
+      return object != null && hasPath(object, path, baseHasIn);
+    }
+
+    /**
+     * Creates an object composed of the inverted keys and values of `object`.
+     * If `object` contains duplicate values, subsequent values overwrite
+     * property assignments of previous values.
      *
      * @static
      * @memberOf _
-     * @category Functions
-     * @param {Function} func The function to throttle.
-     * @param {number} wait The number of milliseconds to throttle executions to.
-     * @param {Object} [options] The options object.
-     * @param {boolean} [options.leading=true] Specify execution on the leading edge of the timeout.
-     * @param {boolean} [options.trailing=true] Specify execution on the trailing edge of the timeout.
-     * @returns {Function} Returns the new throttled function.
+     * @since 0.7.0
+     * @category Object
+     * @param {Object} object The object to invert.
+     * @returns {Object} Returns the new inverted object.
      * @example
      *
-     * // avoid excessively updating the position while scrolling
-     * var throttled = _.throttle(updatePosition, 100);
-     * jQuery(window).on('scroll', throttled);
+     * var object = { 'a': 1, 'b': 2, 'c': 1 };
      *
-     * // execute `renewToken` when the click event is fired, but not more than once every 5 minutes
-     * jQuery('.interactive').on('click', _.throttle(renewToken, 300000, {
-     *   'trailing': false
-     * }));
+     * _.invert(object);
+     * // => { '1': 'c', '2': 'b' }
      */
-    function throttle(func, wait, options) {
-      var leading = true,
-          trailing = true;
+    var invert = createInverter(function(result, value, key) {
+      if (value != null &&
+          typeof value.toString != 'function') {
+        value = nativeObjectToString.call(value);
+      }
+
+      result[value] = key;
+    }, constant(identity));
 
-      if (!isFunction(func)) {
-        throw new TypeError;
+    /**
+     * This method is like `_.invert` except that the inverted object is generated
+     * from the results of running each element of `object` thru `iteratee`. The
+     * corresponding inverted value of each inverted key is an array of keys
+     * responsible for generating the inverted value. The iteratee is invoked
+     * with one argument: (value).
+     *
+     * @static
+     * @memberOf _
+     * @since 4.1.0
+     * @category Object
+     * @param {Object} object The object to invert.
+     * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+     * @returns {Object} Returns the new inverted object.
+     * @example
+     *
+     * var object = { 'a': 1, 'b': 2, 'c': 1 };
+     *
+     * _.invertBy(object);
+     * // => { '1': ['a', 'c'], '2': ['b'] }
+     *
+     * _.invertBy(object, function(value) {
+     *   return 'group' + value;
+     * });
+     * // => { 'group1': ['a', 'c'], 'group2': ['b'] }
+     */
+    var invertBy = createInverter(function(result, value, key) {
+      if (value != null &&
+          typeof value.toString != 'function') {
+        value = nativeObjectToString.call(value);
       }
-      if (options === false) {
-        leading = false;
-      } else if (isObject(options)) {
-        leading = 'leading' in options ? options.leading : leading;
-        trailing = 'trailing' in options ? options.trailing : trailing;
+
+      if (hasOwnProperty.call(result, value)) {
+        result[value].push(key);
+      } else {
+        result[value] = [key];
       }
-      debounceOptions.leading = leading;
-      debounceOptions.maxWait = wait;
-      debounceOptions.trailing = trailing;
+    }, getIteratee);
+
+    /**
+     * Invokes the method at `path` of `object`.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Object
+     * @param {Object} object The object to query.
+     * @param {Array|string} path The path of the method to invoke.
+     * @param {...*} [args] The arguments to invoke the method with.
+     * @returns {*} Returns the result of the invoked method.
+     * @example
+     *
+     * var object = { 'a': [{ 'b': { 'c': [1, 2, 3, 4] } }] };
+     *
+     * _.invoke(object, 'a[0].b.c.slice', 1, 3);
+     * // => [2, 3]
+     */
+    var invoke = baseRest(baseInvoke);
 
-      return debounce(func, wait, debounceOptions);
+    /**
+     * Creates an array of the own enumerable property names of `object`.
+     *
+     * **Note:** Non-object values are coerced to objects. See the
+     * [ES spec](http://ecma-international.org/ecma-262/7.0/#sec-object.keys)
+     * for more details.
+     *
+     * @static
+     * @since 0.1.0
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the array of property names.
+     * @example
+     *
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
+     *
+     * _.keys(new Foo);
+     * // => ['a', 'b'] (iteration order is not guaranteed)
+     *
+     * _.keys('hi');
+     * // => ['0', '1']
+     */
+    function keys(object) {
+      return isArrayLike(object) ? arrayLikeKeys(object) : baseKeys(object);
     }
 
     /**
-     * Creates a function that provides `value` to the wrapper function as its
-     * first argument. Additional arguments provided to the function are appended
-     * to those provided to the wrapper function. The wrapper is executed with
-     * the `this` binding of the created function.
+     * Creates an array of the own and inherited enumerable property names of `object`.
+     *
+     * **Note:** Non-object values are coerced to objects.
      *
      * @static
      * @memberOf _
-     * @category Functions
-     * @param {*} value The value to wrap.
-     * @param {Function} wrapper The wrapper function.
-     * @returns {Function} Returns the new function.
+     * @since 3.0.0
+     * @category Object
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the array of property names.
      * @example
      *
-     * var p = _.wrap(_.escape, function(func, text) {
-     *   return '<p>' + func(text) + '</p>';
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
+     *
+     * _.keysIn(new Foo);
+     * // => ['a', 'b', 'c'] (iteration order is not guaranteed)
+     */
+    function keysIn(object) {
+      return isArrayLike(object) ? arrayLikeKeys(object, true) : baseKeysIn(object);
+    }
+
+    /**
+     * The opposite of `_.mapValues`; this method creates an object with the
+     * same values as `object` and keys generated by running each own enumerable
+     * string keyed property of `object` thru `iteratee`. The iteratee is invoked
+     * with three arguments: (value, key, object).
+     *
+     * @static
+     * @memberOf _
+     * @since 3.8.0
+     * @category Object
+     * @param {Object} object The object to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @returns {Object} Returns the new mapped object.
+     * @see _.mapValues
+     * @example
+     *
+     * _.mapKeys({ 'a': 1, 'b': 2 }, function(value, key) {
+     *   return key + value;
      * });
+     * // => { 'a1': 1, 'b2': 2 }
+     */
+    function mapKeys(object, iteratee) {
+      var result = {};
+      iteratee = getIteratee(iteratee, 3);
+
+      baseForOwn(object, function(value, key, object) {
+        baseAssignValue(result, iteratee(value, key, object), value);
+      });
+      return result;
+    }
+
+    /**
+     * Creates an object with the same keys as `object` and values generated
+     * by running each own enumerable string keyed property of `object` thru
+     * `iteratee`. The iteratee is invoked with three arguments:
+     * (value, key, object).
+     *
+     * @static
+     * @memberOf _
+     * @since 2.4.0
+     * @category Object
+     * @param {Object} object The object to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @returns {Object} Returns the new mapped object.
+     * @see _.mapKeys
+     * @example
+     *
+     * var users = {
+     *   'fred':    { 'user': 'fred',    'age': 40 },
+     *   'pebbles': { 'user': 'pebbles', 'age': 1 }
+     * };
+     *
+     * _.mapValues(users, function(o) { return o.age; });
+     * // => { 'fred': 40, 'pebbles': 1 } (iteration order is not guaranteed)
      *
-     * p('Fred, Wilma, & Pebbles');
-     * // => '<p>Fred, Wilma, &amp; Pebbles</p>'
+     * // The `_.property` iteratee shorthand.
+     * _.mapValues(users, 'age');
+     * // => { 'fred': 40, 'pebbles': 1 } (iteration order is not guaranteed)
      */
-    function wrap(value, wrapper) {
-      return createWrapper(wrapper, 16, [value]);
+    function mapValues(object, iteratee) {
+      var result = {};
+      iteratee = getIteratee(iteratee, 3);
+
+      baseForOwn(object, function(value, key, object) {
+        baseAssignValue(result, key, iteratee(value, key, object));
+      });
+      return result;
     }
 
-    /*--------------------------------------------------------------------------*/
+    /**
+     * This method is like `_.assign` except that it recursively merges own and
+     * inherited enumerable string keyed properties of source objects into the
+     * destination object. Source properties that resolve to `undefined` are
+     * skipped if a destination value exists. Array and plain object properties
+     * are merged recursively. Other objects and value types are overridden by
+     * assignment. Source objects are applied from left to right. Subsequent
+     * sources overwrite property assignments of previous sources.
+     *
+     * **Note:** This method mutates `object`.
+     *
+     * @static
+     * @memberOf _
+     * @since 0.5.0
+     * @category Object
+     * @param {Object} object The destination object.
+     * @param {...Object} [sources] The source objects.
+     * @returns {Object} Returns `object`.
+     * @example
+     *
+     * var object = {
+     *   'a': [{ 'b': 2 }, { 'd': 4 }]
+     * };
+     *
+     * var other = {
+     *   'a': [{ 'c': 3 }, { 'e': 5 }]
+     * };
+     *
+     * _.merge(object, other);
+     * // => { 'a': [{ 'b': 2, 'c': 3 }, { 'd': 4, 'e': 5 }] }
+     */
+    var merge = createAssigner(function(object, source, srcIndex) {
+      baseMerge(object, source, srcIndex);
+    });
 
     /**
-     * Creates a function that returns `value`.
+     * This method is like `_.merge` except that it accepts `customizer` which
+     * is invoked to produce the merged values of the destination and source
+     * properties. If `customizer` returns `undefined`, merging is handled by the
+     * method instead. The `customizer` is invoked with six arguments:
+     * (objValue, srcValue, key, object, source, stack).
+     *
+     * **Note:** This method mutates `object`.
      *
      * @static
      * @memberOf _
-     * @category Utilities
-     * @param {*} value The value to return from the new function.
-     * @returns {Function} Returns the new function.
+     * @since 4.0.0
+     * @category Object
+     * @param {Object} object The destination object.
+     * @param {...Object} sources The source objects.
+     * @param {Function} customizer The function to customize assigned values.
+     * @returns {Object} Returns `object`.
      * @example
      *
-     * var object = { 'name': 'fred' };
-     * var getter = _.constant(object);
-     * getter() === object;
-     * // => true
+     * function customizer(objValue, srcValue) {
+     *   if (_.isArray(objValue)) {
+     *     return objValue.concat(srcValue);
+     *   }
+     * }
+     *
+     * var object = { 'a': [1], 'b': [2] };
+     * var other = { 'a': [3], 'b': [4] };
+     *
+     * _.mergeWith(object, other, customizer);
+     * // => { 'a': [1, 3], 'b': [2, 4] }
      */
-    function constant(value) {
-      return function() {
-        return value;
-      };
+    var mergeWith = createAssigner(function(object, source, srcIndex, customizer) {
+      baseMerge(object, source, srcIndex, customizer);
+    });
+
+    /**
+     * The opposite of `_.pick`; this method creates an object composed of the
+     * own and inherited enumerable property paths of `object` that are not omitted.
+     *
+     * **Note:** This method is considerably slower than `_.pick`.
+     *
+     * @static
+     * @since 0.1.0
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The source object.
+     * @param {...(string|string[])} [paths] The property paths to omit.
+     * @returns {Object} Returns the new object.
+     * @example
+     *
+     * var object = { 'a': 1, 'b': '2', 'c': 3 };
+     *
+     * _.omit(object, ['a', 'c']);
+     * // => { 'b': '2' }
+     */
+    var omit = flatRest(function(object, paths) {
+      var result = {};
+      if (object == null) {
+        return result;
+      }
+      var isDeep = false;
+      paths = arrayMap(paths, function(path) {
+        path = castPath(path, object);
+        isDeep || (isDeep = path.length > 1);
+        return path;
+      });
+      copyObject(object, getAllKeysIn(object), result);
+      if (isDeep) {
+        result = baseClone(result, CLONE_DEEP_FLAG | CLONE_FLAT_FLAG | CLONE_SYMBOLS_FLAG, customOmitClone);
+      }
+      var length = paths.length;
+      while (length--) {
+        baseUnset(result, paths[length]);
+      }
+      return result;
+    });
+
+    /**
+     * The opposite of `_.pickBy`; this method creates an object composed of
+     * the own and inherited enumerable string keyed properties of `object` that
+     * `predicate` doesn't return truthy for. The predicate is invoked with two
+     * arguments: (value, key).
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Object
+     * @param {Object} object The source object.
+     * @param {Function} [predicate=_.identity] The function invoked per property.
+     * @returns {Object} Returns the new object.
+     * @example
+     *
+     * var object = { 'a': 1, 'b': '2', 'c': 3 };
+     *
+     * _.omitBy(object, _.isNumber);
+     * // => { 'b': '2' }
+     */
+    function omitBy(object, predicate) {
+      return pickBy(object, negate(getIteratee(predicate)));
     }
 
     /**
-     * Produces a callback bound to an optional `thisArg`. If `func` is a property
-     * name the created callback will return the property value for a given element.
-     * If `func` is an object the created callback will return `true` for elements
-     * that contain the equivalent object properties, otherwise it will return `false`.
+     * Creates an object composed of the picked `object` properties.
      *
      * @static
+     * @since 0.1.0
      * @memberOf _
-     * @category Utilities
-     * @param {*} [func=identity] The value to convert to a callback.
-     * @param {*} [thisArg] The `this` binding of the created callback.
-     * @param {number} [argCount] The number of arguments the callback accepts.
-     * @returns {Function} Returns a callback function.
+     * @category Object
+     * @param {Object} object The source object.
+     * @param {...(string|string[])} [paths] The property paths to pick.
+     * @returns {Object} Returns the new object.
      * @example
      *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
-     * ];
+     * var object = { 'a': 1, 'b': '2', 'c': 3 };
      *
-     * // wrap to create custom callback shorthands
-     * _.createCallback = _.wrap(_.createCallback, function(func, callback, thisArg) {
-     *   var match = /^(.+?)__([gl]t)(.+)$/.exec(callback);
-     *   return !match ? func(callback, thisArg) : function(object) {
-     *     return match[2] == 'gt' ? object[match[1]] > match[3] : object[match[1]] < match[3];
-     *   };
-     * });
+     * _.pick(object, ['a', 'c']);
+     * // => { 'a': 1, 'c': 3 }
+     */
+    var pick = flatRest(function(object, paths) {
+      return object == null ? {} : basePick(object, paths);
+    });
+
+    /**
+     * Creates an object composed of the `object` properties `predicate` returns
+     * truthy for. The predicate is invoked with two arguments: (value, key).
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Object
+     * @param {Object} object The source object.
+     * @param {Function} [predicate=_.identity] The function invoked per property.
+     * @returns {Object} Returns the new object.
+     * @example
      *
-     * _.filter(characters, 'age__gt38');
-     * // => [{ 'name': 'fred', 'age': 40 }]
+     * var object = { 'a': 1, 'b': '2', 'c': 3 };
+     *
+     * _.pickBy(object, _.isNumber);
+     * // => { 'a': 1, 'c': 3 }
      */
-    function createCallback(func, thisArg, argCount) {
-      var type = typeof func;
-      if (func == null || type == 'function') {
-        return baseCreateCallback(func, thisArg, argCount);
-      }
-      // handle "_.pluck" style callback shorthands
-      if (type != 'object') {
-        return property(func);
-      }
-      var props = keys(func),
-          key = props[0],
-          a = func[key];
-
-      // handle "_.where" style callback shorthands
-      if (props.length == 1 && a === a && !isObject(a)) {
-        // fast path the common case of providing an object with a single
-        // property containing a primitive value
-        return function(object) {
-          var b = object[key];
-          return a === b && (a !== 0 || (1 / a == 1 / b));
-        };
+    function pickBy(object, predicate) {
+      if (object == null) {
+        return {};
       }
-      return function(object) {
-        var length = props.length,
-            result = false;
+      var props = arrayMap(getAllKeysIn(object), function(prop) {
+        return [prop];
+      });
+      predicate = getIteratee(predicate);
+      return basePickBy(object, props, function(value, path) {
+        return predicate(value, path[0]);
+      });
+    }
 
-        while (length--) {
-          if (!(result = baseIsEqual(object[props[length]], func[props[length]], null, true))) {
-            break;
-          }
+    /**
+     * This method is like `_.get` except that if the resolved value is a
+     * function it's invoked with the `this` binding of its parent object and
+     * its result is returned.
+     *
+     * @static
+     * @since 0.1.0
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to query.
+     * @param {Array|string} path The path of the property to resolve.
+     * @param {*} [defaultValue] The value returned for `undefined` resolved values.
+     * @returns {*} Returns the resolved value.
+     * @example
+     *
+     * var object = { 'a': [{ 'b': { 'c1': 3, 'c2': _.constant(4) } }] };
+     *
+     * _.result(object, 'a[0].b.c1');
+     * // => 3
+     *
+     * _.result(object, 'a[0].b.c2');
+     * // => 4
+     *
+     * _.result(object, 'a[0].b.c3', 'default');
+     * // => 'default'
+     *
+     * _.result(object, 'a[0].b.c3', _.constant('default'));
+     * // => 'default'
+     */
+    function result(object, path, defaultValue) {
+      path = castPath(path, object);
+
+      var index = -1,
+          length = path.length;
+
+      // Ensure the loop is entered when path is empty.
+      if (!length) {
+        length = 1;
+        object = undefined;
+      }
+      while (++index < length) {
+        var value = object == null ? undefined : object[toKey(path[index])];
+        if (value === undefined) {
+          index = length;
+          value = defaultValue;
         }
-        return result;
-      };
+        object = isFunction(value) ? value.call(object) : value;
+      }
+      return object;
     }
 
     /**
-     * Converts the characters `&`, `<`, `>`, `"`, and `'` in `string` to their
-     * corresponding HTML entities.
+     * Sets the value at `path` of `object`. If a portion of `path` doesn't exist,
+     * it's created. Arrays are created for missing index properties while objects
+     * are created for all other missing properties. Use `_.setWith` to customize
+     * `path` creation.
+     *
+     * **Note:** This method mutates `object`.
      *
      * @static
      * @memberOf _
-     * @category Utilities
-     * @param {string} string The string to escape.
-     * @returns {string} Returns the escaped string.
+     * @since 3.7.0
+     * @category Object
+     * @param {Object} object The object to modify.
+     * @param {Array|string} path The path of the property to set.
+     * @param {*} value The value to set.
+     * @returns {Object} Returns `object`.
      * @example
      *
-     * _.escape('Fred, Wilma, & Pebbles');
-     * // => 'Fred, Wilma, &amp; Pebbles'
+     * var object = { 'a': [{ 'b': { 'c': 3 } }] };
+     *
+     * _.set(object, 'a[0].b.c', 4);
+     * console.log(object.a[0].b.c);
+     * // => 4
+     *
+     * _.set(object, ['x', '0', 'y', 'z'], 5);
+     * console.log(object.x[0].y.z);
+     * // => 5
      */
-    function escape(string) {
-      return string == null ? '' : String(string).replace(reUnescapedHtml, escapeHtmlChar);
+    function set(object, path, value) {
+      return object == null ? object : baseSet(object, path, value);
     }
 
     /**
-     * This method returns the first argument provided to it.
+     * This method is like `_.set` except that it accepts `customizer` which is
+     * invoked to produce the objects of `path`.  If `customizer` returns `undefined`
+     * path creation is handled by the method instead. The `customizer` is invoked
+     * with three arguments: (nsValue, key, nsObject).
+     *
+     * **Note:** This method mutates `object`.
      *
      * @static
      * @memberOf _
-     * @category Utilities
-     * @param {*} value Any value.
-     * @returns {*} Returns `value`.
+     * @since 4.0.0
+     * @category Object
+     * @param {Object} object The object to modify.
+     * @param {Array|string} path The path of the property to set.
+     * @param {*} value The value to set.
+     * @param {Function} [customizer] The function to customize assigned values.
+     * @returns {Object} Returns `object`.
      * @example
      *
-     * var object = { 'name': 'fred' };
-     * _.identity(object) === object;
-     * // => true
+     * var object = {};
+     *
+     * _.setWith(object, '[0][1]', 'a', Object);
+     * // => { '0': { '1': 'a' } }
      */
-    function identity(value) {
-      return value;
+    function setWith(object, path, value, customizer) {
+      customizer = typeof customizer == 'function' ? customizer : undefined;
+      return object == null ? object : baseSet(object, path, value, customizer);
     }
 
     /**
-     * Adds function properties of a source object to the destination object.
-     * If `object` is a function methods will be added to its prototype as well.
+     * Creates an array of own enumerable string keyed-value pairs for `object`
+     * which can be consumed by `_.fromPairs`. If `object` is a map or set, its
+     * entries are returned.
      *
      * @static
      * @memberOf _
-     * @category Utilities
-     * @param {Function|Object} [object=lodash] object The destination object.
-     * @param {Object} source The object of functions to add.
-     * @param {Object} [options] The options object.
-     * @param {boolean} [options.chain=true] Specify whether the functions added are chainable.
+     * @since 4.0.0
+     * @alias entries
+     * @category Object
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the key-value pairs.
      * @example
      *
-     * function capitalize(string) {
-     *   return string.charAt(0).toUpperCase() + string.slice(1).toLowerCase();
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
      * }
      *
-     * _.mixin({ 'capitalize': capitalize });
-     * _.capitalize('fred');
-     * // => 'Fred'
-     *
-     * _('fred').capitalize().value();
-     * // => 'Fred'
+     * Foo.prototype.c = 3;
      *
-     * _.mixin({ 'capitalize': capitalize }, { 'chain': false });
-     * _('fred').capitalize();
-     * // => 'Fred'
+     * _.toPairs(new Foo);
+     * // => [['a', 1], ['b', 2]] (iteration order is not guaranteed)
      */
-    function mixin(object, source, options) {
-      var chain = true,
-          methodNames = source && functions(source);
+    var toPairs = createToPairs(keys);
 
-      if (!source || (!options && !methodNames.length)) {
-        if (options == null) {
-          options = source;
-        }
-        ctor = lodashWrapper;
-        source = object;
-        object = lodash;
-        methodNames = functions(source);
-      }
-      if (options === false) {
-        chain = false;
-      } else if (isObject(options) && 'chain' in options) {
-        chain = options.chain;
-      }
-      var ctor = object,
-          isFunc = isFunction(ctor);
+    /**
+     * Creates an array of own and inherited enumerable string keyed-value pairs
+     * for `object` which can be consumed by `_.fromPairs`. If `object` is a map
+     * or set, its entries are returned.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @alias entriesIn
+     * @category Object
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the key-value pairs.
+     * @example
+     *
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
+     *
+     * _.toPairsIn(new Foo);
+     * // => [['a', 1], ['b', 2], ['c', 3]] (iteration order is not guaranteed)
+     */
+    var toPairsIn = createToPairs(keysIn);
 
-      forEach(methodNames, function(methodName) {
-        var func = object[methodName] = source[methodName];
-        if (isFunc) {
-          ctor.prototype[methodName] = function() {
-            var chainAll = this.__chain__,
-                value = this.__wrapped__,
-                args = [value];
+    /**
+     * An alternative to `_.reduce`; this method transforms `object` to a new
+     * `accumulator` object which is the result of running each of its own
+     * enumerable string keyed properties thru `iteratee`, with each invocation
+     * potentially mutating the `accumulator` object. If `accumulator` is not
+     * provided, a new object with the same `[[Prototype]]` will be used. The
+     * iteratee is invoked with four arguments: (accumulator, value, key, object).
+     * Iteratee functions may exit iteration early by explicitly returning `false`.
+     *
+     * @static
+     * @memberOf _
+     * @since 1.3.0
+     * @category Object
+     * @param {Object} object The object to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {*} [accumulator] The custom accumulator value.
+     * @returns {*} Returns the accumulated value.
+     * @example
+     *
+     * _.transform([2, 3, 4], function(result, n) {
+     *   result.push(n *= n);
+     *   return n % 2 == 0;
+     * }, []);
+     * // => [4, 9]
+     *
+     * _.transform({ 'a': 1, 'b': 2, 'c': 1 }, function(result, value, key) {
+     *   (result[value] || (result[value] = [])).push(key);
+     * }, {});
+     * // => { '1': ['a', 'c'], '2': ['b'] }
+     */
+    function transform(object, iteratee, accumulator) {
+      var isArr = isArray(object),
+          isArrLike = isArr || isBuffer(object) || isTypedArray(object);
 
-            push.apply(args, arguments);
-            var result = func.apply(object, args);
-            if (chain || chainAll) {
-              if (value === result && isObject(result)) {
-                return this;
-              }
-              result = new ctor(result);
-              result.__chain__ = chainAll;
-            }
-            return result;
-          };
+      iteratee = getIteratee(iteratee, 4);
+      if (accumulator == null) {
+        var Ctor = object && object.constructor;
+        if (isArrLike) {
+          accumulator = isArr ? new Ctor : [];
+        }
+        else if (isObject(object)) {
+          accumulator = isFunction(Ctor) ? baseCreate(getPrototype(object)) : {};
+        }
+        else {
+          accumulator = {};
         }
+      }
+      (isArrLike ? arrayEach : baseForOwn)(object, function(value, index, object) {
+        return iteratee(accumulator, value, index, object);
       });
+      return accumulator;
     }
 
     /**
-     * Reverts the '_' variable to its previous value and returns a reference to
-     * the `lodash` function.
+     * Removes the property at `path` of `object`.
+     *
+     * **Note:** This method mutates `object`.
      *
      * @static
      * @memberOf _
-     * @category Utilities
-     * @returns {Function} Returns the `lodash` function.
+     * @since 4.0.0
+     * @category Object
+     * @param {Object} object The object to modify.
+     * @param {Array|string} path The path of the property to unset.
+     * @returns {boolean} Returns `true` if the property is deleted, else `false`.
      * @example
      *
-     * var lodash = _.noConflict();
+     * var object = { 'a': [{ 'b': { 'c': 7 } }] };
+     * _.unset(object, 'a[0].b.c');
+     * // => true
+     *
+     * console.log(object);
+     * // => { 'a': [{ 'b': {} }] };
+     *
+     * _.unset(object, ['a', '0', 'b', 'c']);
+     * // => true
+     *
+     * console.log(object);
+     * // => { 'a': [{ 'b': {} }] };
      */
-    function noConflict() {
-      context._ = oldDash;
-      return this;
+    function unset(object, path) {
+      return object == null ? true : baseUnset(object, path);
     }
 
     /**
-     * A no-operation function.
+     * This method is like `_.set` except that accepts `updater` to produce the
+     * value to set. Use `_.updateWith` to customize `path` creation. The `updater`
+     * is invoked with one argument: (value).
+     *
+     * **Note:** This method mutates `object`.
      *
      * @static
      * @memberOf _
-     * @category Utilities
+     * @since 4.6.0
+     * @category Object
+     * @param {Object} object The object to modify.
+     * @param {Array|string} path The path of the property to set.
+     * @param {Function} updater The function to produce the updated value.
+     * @returns {Object} Returns `object`.
      * @example
      *
-     * var object = { 'name': 'fred' };
-     * _.noop(object) === undefined;
-     * // => true
+     * var object = { 'a': [{ 'b': { 'c': 3 } }] };
+     *
+     * _.update(object, 'a[0].b.c', function(n) { return n * n; });
+     * console.log(object.a[0].b.c);
+     * // => 9
+     *
+     * _.update(object, 'x[0].y.z', function(n) { return n ? n + 1 : 0; });
+     * console.log(object.x[0].y.z);
+     * // => 0
      */
-    function noop() {
-      // no operation performed
+    function update(object, path, updater) {
+      return object == null ? object : baseUpdate(object, path, castFunction(updater));
     }
 
     /**
-     * Gets the number of milliseconds that have elapsed since the Unix epoch
-     * (1 January 1970 00:00:00 UTC).
+     * This method is like `_.update` except that it accepts `customizer` which is
+     * invoked to produce the objects of `path`.  If `customizer` returns `undefined`
+     * path creation is handled by the method instead. The `customizer` is invoked
+     * with three arguments: (nsValue, key, nsObject).
+     *
+     * **Note:** This method mutates `object`.
      *
      * @static
      * @memberOf _
-     * @category Utilities
+     * @since 4.6.0
+     * @category Object
+     * @param {Object} object The object to modify.
+     * @param {Array|string} path The path of the property to set.
+     * @param {Function} updater The function to produce the updated value.
+     * @param {Function} [customizer] The function to customize assigned values.
+     * @returns {Object} Returns `object`.
      * @example
      *
-     * var stamp = _.now();
-     * _.defer(function() { console.log(_.now() - stamp); });
-     * // => logs the number of milliseconds it took for the deferred function to be called
+     * var object = {};
+     *
+     * _.updateWith(object, '[0][1]', _.constant('a'), Object);
+     * // => { '0': { '1': 'a' } }
      */
-    var now = isNative(now = Date.now) && now || function() {
-      return new Date().getTime();
-    };
+    function updateWith(object, path, updater, customizer) {
+      customizer = typeof customizer == 'function' ? customizer : undefined;
+      return object == null ? object : baseUpdate(object, path, castFunction(updater), customizer);
+    }
 
     /**
-     * Converts the given value into an integer of the specified radix.
-     * If `radix` is `undefined` or `0` a `radix` of `10` is used unless the
-     * `value` is a hexadecimal, in which case a `radix` of `16` is used.
+     * Creates an array of the own enumerable string keyed property values of `object`.
      *
-     * Note: This method avoids differences in native ES3 and ES5 `parseInt`
-     * implementations. See http://es5.github.io/#E.
+     * **Note:** Non-object values are coerced to objects.
      *
      * @static
+     * @since 0.1.0
      * @memberOf _
-     * @category Utilities
-     * @param {string} value The value to parse.
-     * @param {number} [radix] The radix used to interpret the value to parse.
-     * @returns {number} Returns the new integer value.
+     * @category Object
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the array of property values.
      * @example
      *
-     * _.parseInt('08');
-     * // => 8
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
+     *
+     * _.values(new Foo);
+     * // => [1, 2] (iteration order is not guaranteed)
+     *
+     * _.values('hi');
+     * // => ['h', 'i']
      */
-    var parseInt = nativeParseInt(whitespace + '08') == 8 ? nativeParseInt : function(value, radix) {
-      // Firefox < 21 and Opera < 15 follow the ES3 specified implementation of `parseInt`
-      return nativeParseInt(isString(value) ? value.replace(reLeadingSpacesAndZeros, '') : value, radix || 0);
-    };
+    function values(object) {
+      return object == null ? [] : baseValues(object, keys(object));
+    }
 
     /**
-     * Creates a "_.pluck" style function, which returns the `key` value of a
-     * given object.
+     * Creates an array of the own and inherited enumerable string keyed property
+     * values of `object`.
+     *
+     * **Note:** Non-object values are coerced to objects.
      *
      * @static
      * @memberOf _
-     * @category Utilities
-     * @param {string} key The name of the property to retrieve.
-     * @returns {Function} Returns the new function.
+     * @since 3.0.0
+     * @category Object
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the array of property values.
      * @example
      *
-     * var characters = [
-     *   { 'name': 'fred',   'age': 40 },
-     *   { 'name': 'barney', 'age': 36 }
-     * ];
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
      *
-     * var getName = _.property('name');
+     * Foo.prototype.c = 3;
      *
-     * _.map(characters, getName);
-     * // => ['barney', 'fred']
+     * _.valuesIn(new Foo);
+     * // => [1, 2, 3] (iteration order is not guaranteed)
+     */
+    function valuesIn(object) {
+      return object == null ? [] : baseValues(object, keysIn(object));
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Clamps `number` within the inclusive `lower` and `upper` bounds.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Number
+     * @param {number} number The number to clamp.
+     * @param {number} [lower] The lower bound.
+     * @param {number} upper The upper bound.
+     * @returns {number} Returns the clamped number.
+     * @example
      *
-     * _.sortBy(characters, getName);
-     * // => [{ 'name': 'barney', 'age': 36 }, { 'name': 'fred',   'age': 40 }]
+     * _.clamp(-10, -5, 5);
+     * // => -5
+     *
+     * _.clamp(10, -5, 5);
+     * // => 5
      */
-    function property(key) {
-      return function(object) {
-        return object[key];
-      };
+    function clamp(number, lower, upper) {
+      if (upper === undefined) {
+        upper = lower;
+        lower = undefined;
+      }
+      if (upper !== undefined) {
+        upper = toNumber(upper);
+        upper = upper === upper ? upper : 0;
+      }
+      if (lower !== undefined) {
+        lower = toNumber(lower);
+        lower = lower === lower ? lower : 0;
+      }
+      return baseClamp(toNumber(number), lower, upper);
     }
 
     /**
-     * Produces a random number between `min` and `max` (inclusive). If only one
-     * argument is provided a number between `0` and the given number will be
-     * returned. If `floating` is truey or either `min` or `max` are floats a
-     * floating-point number will be returned instead of an integer.
+     * Checks if `n` is between `start` and up to, but not including, `end`. If
+     * `end` is not specified, it's set to `start` with `start` then set to `0`.
+     * If `start` is greater than `end` the params are swapped to support
+     * negative ranges.
      *
      * @static
      * @memberOf _
-     * @category Utilities
-     * @param {number} [min=0] The minimum possible value.
-     * @param {number} [max=1] The maximum possible value.
-     * @param {boolean} [floating=false] Specify returning a floating-point number.
-     * @returns {number} Returns a random number.
+     * @since 3.3.0
+     * @category Number
+     * @param {number} number The number to check.
+     * @param {number} [start=0] The start of the range.
+     * @param {number} end The end of the range.
+     * @returns {boolean} Returns `true` if `number` is in the range, else `false`.
+     * @see _.range, _.rangeRight
+     * @example
+     *
+     * _.inRange(3, 2, 4);
+     * // => true
+     *
+     * _.inRange(4, 8);
+     * // => true
+     *
+     * _.inRange(4, 2);
+     * // => false
+     *
+     * _.inRange(2, 2);
+     * // => false
+     *
+     * _.inRange(1.2, 2);
+     * // => true
+     *
+     * _.inRange(5.2, 4);
+     * // => false
+     *
+     * _.inRange(-3, -2, -6);
+     * // => true
+     */
+    function inRange(number, start, end) {
+      start = toFinite(start);
+      if (end === undefined) {
+        end = start;
+        start = 0;
+      } else {
+        end = toFinite(end);
+      }
+      number = toNumber(number);
+      return baseInRange(number, start, end);
+    }
+
+    /**
+     * Produces a random number between the inclusive `lower` and `upper` bounds.
+     * If only one argument is provided a number between `0` and the given number
+     * is returned. If `floating` is `true`, or either `lower` or `upper` are
+     * floats, a floating-point number is returned instead of an integer.
+     *
+     * **Note:** JavaScript follows the IEEE-754 standard for resolving
+     * floating-point values which can produce unexpected results.
+     *
+     * @static
+     * @memberOf _
+     * @since 0.7.0
+     * @category Number
+     * @param {number} [lower=0] The lower bound.
+     * @param {number} [upper=1] The upper bound.
+     * @param {boolean} [floating] Specify returning a floating-point number.
+     * @returns {number} Returns the random number.
      * @example
      *
      * _.random(0, 5);
@@ -6434,178 +14143,721 @@
      * _.random(1.2, 5.2);
      * // => a floating-point number between 1.2 and 5.2
      */
-    function random(min, max, floating) {
-      var noMin = min == null,
-          noMax = max == null;
-
-      if (floating == null) {
-        if (typeof min == 'boolean' && noMax) {
-          floating = min;
-          min = 1;
-        }
-        else if (!noMax && typeof max == 'boolean') {
-          floating = max;
-          noMax = true;
-        }
-      }
-      if (noMin && noMax) {
-        max = 1;
-      }
-      min = +min || 0;
-      if (noMax) {
-        max = min;
-        min = 0;
-      } else {
-        max = +max || 0;
+    function random(lower, upper, floating) {
+      if (floating && typeof floating != 'boolean' && isIterateeCall(lower, upper, floating)) {
+        upper = floating = undefined;
+      }
+      if (floating === undefined) {
+        if (typeof upper == 'boolean') {
+          floating = upper;
+          upper = undefined;
+        }
+        else if (typeof lower == 'boolean') {
+          floating = lower;
+          lower = undefined;
+        }
+      }
+      if (lower === undefined && upper === undefined) {
+        lower = 0;
+        upper = 1;
       }
-      if (floating || min % 1 || max % 1) {
+      else {
+        lower = toFinite(lower);
+        if (upper === undefined) {
+          upper = lower;
+          lower = 0;
+        } else {
+          upper = toFinite(upper);
+        }
+      }
+      if (lower > upper) {
+        var temp = lower;
+        lower = upper;
+        upper = temp;
+      }
+      if (floating || lower % 1 || upper % 1) {
         var rand = nativeRandom();
-        return nativeMin(min + (rand * (max - min + parseFloat('1e-' + ((rand +'').length - 1)))), max);
+        return nativeMin(lower + (rand * (upper - lower + freeParseFloat('1e-' + ((rand + '').length - 1)))), upper);
       }
-      return baseRandom(min, max);
+      return baseRandom(lower, upper);
     }
 
+    /*------------------------------------------------------------------------*/
+
     /**
-     * Resolves the value of property `key` on `object`. If `key` is a function
-     * it will be invoked with the `this` binding of `object` and its result returned,
-     * else the property value is returned. If `object` is falsey then `undefined`
-     * is returned.
+     * Converts `string` to [camel case](https://en.wikipedia.org/wiki/CamelCase).
      *
      * @static
      * @memberOf _
-     * @category Utilities
-     * @param {Object} object The object to inspect.
-     * @param {string} key The name of the property to resolve.
-     * @returns {*} Returns the resolved value.
+     * @since 3.0.0
+     * @category String
+     * @param {string} [string=''] The string to convert.
+     * @returns {string} Returns the camel cased string.
      * @example
      *
-     * var object = {
-     *   'cheese': 'crumpets',
-     *   'stuff': function() {
-     *     return 'nonsense';
-     *   }
-     * };
+     * _.camelCase('Foo Bar');
+     * // => 'fooBar'
+     *
+     * _.camelCase('--foo-bar--');
+     * // => 'fooBar'
+     *
+     * _.camelCase('__FOO_BAR__');
+     * // => 'fooBar'
+     */
+    var camelCase = createCompounder(function(result, word, index) {
+      word = word.toLowerCase();
+      return result + (index ? capitalize(word) : word);
+    });
+
+    /**
+     * Converts the first character of `string` to upper case and the remaining
+     * to lower case.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category String
+     * @param {string} [string=''] The string to capitalize.
+     * @returns {string} Returns the capitalized string.
+     * @example
+     *
+     * _.capitalize('FRED');
+     * // => 'Fred'
+     */
+    function capitalize(string) {
+      return upperFirst(toString(string).toLowerCase());
+    }
+
+    /**
+     * Deburrs `string` by converting
+     * [Latin-1 Supplement](https://en.wikipedia.org/wiki/Latin-1_Supplement_(Unicode_block)#Character_table)
+     * and [Latin Extended-A](https://en.wikipedia.org/wiki/Latin_Extended-A)
+     * letters to basic Latin letters and removing
+     * [combining diacritical marks](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks).
      *
-     * _.result(object, 'cheese');
-     * // => 'crumpets'
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category String
+     * @param {string} [string=''] The string to deburr.
+     * @returns {string} Returns the deburred string.
+     * @example
      *
-     * _.result(object, 'stuff');
-     * // => 'nonsense'
+     * _.deburr('déjà vu');
+     * // => 'deja vu'
      */
-    function result(object, key) {
-      if (object) {
-        var value = object[key];
-        return isFunction(value) ? object[key]() : value;
+    function deburr(string) {
+      string = toString(string);
+      return string && string.replace(reLatin, deburrLetter).replace(reComboMark, '');
+    }
+
+    /**
+     * Checks if `string` ends with the given target string.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category String
+     * @param {string} [string=''] The string to inspect.
+     * @param {string} [target] The string to search for.
+     * @param {number} [position=string.length] The position to search up to.
+     * @returns {boolean} Returns `true` if `string` ends with `target`,
+     *  else `false`.
+     * @example
+     *
+     * _.endsWith('abc', 'c');
+     * // => true
+     *
+     * _.endsWith('abc', 'b');
+     * // => false
+     *
+     * _.endsWith('abc', 'b', 2);
+     * // => true
+     */
+    function endsWith(string, target, position) {
+      string = toString(string);
+      target = baseToString(target);
+
+      var length = string.length;
+      position = position === undefined
+        ? length
+        : baseClamp(toInteger(position), 0, length);
+
+      var end = position;
+      position -= target.length;
+      return position >= 0 && string.slice(position, end) == target;
+    }
+
+    /**
+     * Converts the characters "&", "<", ">", '"', and "'" in `string` to their
+     * corresponding HTML entities.
+     *
+     * **Note:** No other characters are escaped. To escape additional
+     * characters use a third-party library like [_he_](https://mths.be/he).
+     *
+     * Though the ">" character is escaped for symmetry, characters like
+     * ">" and "/" don't need escaping in HTML and have no special meaning
+     * unless they're part of a tag or unquoted attribute value. See
+     * [Mathias Bynens's article](https://mathiasbynens.be/notes/ambiguous-ampersands)
+     * (under "semi-related fun fact") for more details.
+     *
+     * When working with HTML you should always
+     * [quote attribute values](http://wonko.com/post/html-escaping) to reduce
+     * XSS vectors.
+     *
+     * @static
+     * @since 0.1.0
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to escape.
+     * @returns {string} Returns the escaped string.
+     * @example
+     *
+     * _.escape('fred, barney, & pebbles');
+     * // => 'fred, barney, &amp; pebbles'
+     */
+    function escape(string) {
+      string = toString(string);
+      return (string && reHasUnescapedHtml.test(string))
+        ? string.replace(reUnescapedHtml, escapeHtmlChar)
+        : string;
+    }
+
+    /**
+     * Escapes the `RegExp` special characters "^", "$", "\", ".", "*", "+",
+     * "?", "(", ")", "[", "]", "{", "}", and "|" in `string`.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category String
+     * @param {string} [string=''] The string to escape.
+     * @returns {string} Returns the escaped string.
+     * @example
+     *
+     * _.escapeRegExp('[lodash](https://lodash.com/)');
+     * // => '\[lodash\]\(https://lodash\.com/\)'
+     */
+    function escapeRegExp(string) {
+      string = toString(string);
+      return (string && reHasRegExpChar.test(string))
+        ? string.replace(reRegExpChar, '\\$&')
+        : string;
+    }
+
+    /**
+     * Converts `string` to
+     * [kebab case](https://en.wikipedia.org/wiki/Letter_case#Special_case_styles).
+     *
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category String
+     * @param {string} [string=''] The string to convert.
+     * @returns {string} Returns the kebab cased string.
+     * @example
+     *
+     * _.kebabCase('Foo Bar');
+     * // => 'foo-bar'
+     *
+     * _.kebabCase('fooBar');
+     * // => 'foo-bar'
+     *
+     * _.kebabCase('__FOO_BAR__');
+     * // => 'foo-bar'
+     */
+    var kebabCase = createCompounder(function(result, word, index) {
+      return result + (index ? '-' : '') + word.toLowerCase();
+    });
+
+    /**
+     * Converts `string`, as space separated words, to lower case.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category String
+     * @param {string} [string=''] The string to convert.
+     * @returns {string} Returns the lower cased string.
+     * @example
+     *
+     * _.lowerCase('--Foo-Bar--');
+     * // => 'foo bar'
+     *
+     * _.lowerCase('fooBar');
+     * // => 'foo bar'
+     *
+     * _.lowerCase('__FOO_BAR__');
+     * // => 'foo bar'
+     */
+    var lowerCase = createCompounder(function(result, word, index) {
+      return result + (index ? ' ' : '') + word.toLowerCase();
+    });
+
+    /**
+     * Converts the first character of `string` to lower case.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category String
+     * @param {string} [string=''] The string to convert.
+     * @returns {string} Returns the converted string.
+     * @example
+     *
+     * _.lowerFirst('Fred');
+     * // => 'fred'
+     *
+     * _.lowerFirst('FRED');
+     * // => 'fRED'
+     */
+    var lowerFirst = createCaseFirst('toLowerCase');
+
+    /**
+     * Pads `string` on the left and right sides if it's shorter than `length`.
+     * Padding characters are truncated if they can't be evenly divided by `length`.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category String
+     * @param {string} [string=''] The string to pad.
+     * @param {number} [length=0] The padding length.
+     * @param {string} [chars=' '] The string used as padding.
+     * @returns {string} Returns the padded string.
+     * @example
+     *
+     * _.pad('abc', 8);
+     * // => '  abc   '
+     *
+     * _.pad('abc', 8, '_-');
+     * // => '_-abc_-_'
+     *
+     * _.pad('abc', 3);
+     * // => 'abc'
+     */
+    function pad(string, length, chars) {
+      string = toString(string);
+      length = toInteger(length);
+
+      var strLength = length ? stringSize(string) : 0;
+      if (!length || strLength >= length) {
+        return string;
       }
+      var mid = (length - strLength) / 2;
+      return (
+        createPadding(nativeFloor(mid), chars) +
+        string +
+        createPadding(nativeCeil(mid), chars)
+      );
     }
 
     /**
-     * A micro-templating method that handles arbitrary delimiters, preserves
-     * whitespace, and correctly escapes quotes within interpolated code.
+     * Pads `string` on the right side if it's shorter than `length`. Padding
+     * characters are truncated if they exceed `length`.
      *
-     * Note: In the development build, `_.template` utilizes sourceURLs for easier
-     * debugging. See http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/#toc-sourceurl
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category String
+     * @param {string} [string=''] The string to pad.
+     * @param {number} [length=0] The padding length.
+     * @param {string} [chars=' '] The string used as padding.
+     * @returns {string} Returns the padded string.
+     * @example
      *
-     * For more information on precompiling templates see:
-     * https://lodash.com/custom-builds
+     * _.padEnd('abc', 6);
+     * // => 'abc   '
      *
-     * For more information on Chrome extension sandboxes see:
-     * http://developer.chrome.com/stable/extensions/sandboxingEval.html
+     * _.padEnd('abc', 6, '_-');
+     * // => 'abc_-_'
+     *
+     * _.padEnd('abc', 3);
+     * // => 'abc'
+     */
+    function padEnd(string, length, chars) {
+      string = toString(string);
+      length = toInteger(length);
+
+      var strLength = length ? stringSize(string) : 0;
+      return (length && strLength < length)
+        ? (string + createPadding(length - strLength, chars))
+        : string;
+    }
+
+    /**
+     * Pads `string` on the left side if it's shorter than `length`. Padding
+     * characters are truncated if they exceed `length`.
      *
      * @static
      * @memberOf _
-     * @category Utilities
-     * @param {string} text The template text.
-     * @param {Object} data The data object used to populate the text.
-     * @param {Object} [options] The options object.
-     * @param {RegExp} [options.escape] The "escape" delimiter.
-     * @param {RegExp} [options.evaluate] The "evaluate" delimiter.
-     * @param {Object} [options.imports] An object to import into the template as local variables.
-     * @param {RegExp} [options.interpolate] The "interpolate" delimiter.
-     * @param {string} [sourceURL] The sourceURL of the template's compiled source.
-     * @param {string} [variable] The data object variable name.
-     * @returns {Function|string} Returns a compiled function when no `data` object
-     *  is given, else it returns the interpolated text.
+     * @since 4.0.0
+     * @category String
+     * @param {string} [string=''] The string to pad.
+     * @param {number} [length=0] The padding length.
+     * @param {string} [chars=' '] The string used as padding.
+     * @returns {string} Returns the padded string.
      * @example
      *
-     * // using the "interpolate" delimiter to create a compiled template
-     * var compiled = _.template('hello <%= name %>');
-     * compiled({ 'name': 'fred' });
-     * // => 'hello fred'
+     * _.padStart('abc', 6);
+     * // => '   abc'
      *
-     * // using the "escape" delimiter to escape HTML in data property values
-     * _.template('<b><%- value %></b>', { 'value': '<script>' });
-     * // => '<b>&lt;script&gt;</b>'
+     * _.padStart('abc', 6, '_-');
+     * // => '_-_abc'
      *
-     * // using the "evaluate" delimiter to generate HTML
-     * var list = '<% _.forEach(people, function(name) { %><li><%- name %></li><% }); %>';
-     * _.template(list, { 'people': ['fred', 'barney'] });
-     * // => '<li>fred</li><li>barney</li>'
+     * _.padStart('abc', 3);
+     * // => 'abc'
+     */
+    function padStart(string, length, chars) {
+      string = toString(string);
+      length = toInteger(length);
+
+      var strLength = length ? stringSize(string) : 0;
+      return (length && strLength < length)
+        ? (createPadding(length - strLength, chars) + string)
+        : string;
+    }
+
+    /**
+     * Converts `string` to an integer of the specified radix. If `radix` is
+     * `undefined` or `0`, a `radix` of `10` is used unless `value` is a
+     * hexadecimal, in which case a `radix` of `16` is used.
      *
-     * // using the ES6 delimiter as an alternative to the default "interpolate" delimiter
-     * _.template('hello ${ name }', { 'name': 'pebbles' });
-     * // => 'hello pebbles'
+     * **Note:** This method aligns with the
+     * [ES5 implementation](https://es5.github.io/#x15.1.2.2) of `parseInt`.
      *
-     * // using the internal `print` function in "evaluate" delimiters
-     * _.template('<% print("hello " + name); %>!', { 'name': 'barney' });
-     * // => 'hello barney!'
+     * @static
+     * @memberOf _
+     * @since 1.1.0
+     * @category String
+     * @param {string} string The string to convert.
+     * @param {number} [radix=10] The radix to interpret `value` by.
+     * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
+     * @returns {number} Returns the converted integer.
+     * @example
      *
-     * // using a custom template delimiters
-     * _.templateSettings = {
-     *   'interpolate': /{{([\s\S]+?)}}/g
-     * };
+     * _.parseInt('08');
+     * // => 8
      *
-     * _.template('hello {{ name }}!', { 'name': 'mustache' });
-     * // => 'hello mustache!'
+     * _.map(['6', '08', '10'], _.parseInt);
+     * // => [6, 8, 10]
+     */
+    function parseInt(string, radix, guard) {
+      if (guard || radix == null) {
+        radix = 0;
+      } else if (radix) {
+        radix = +radix;
+      }
+      return nativeParseInt(toString(string).replace(reTrimStart, ''), radix || 0);
+    }
+
+    /**
+     * Repeats the given string `n` times.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category String
+     * @param {string} [string=''] The string to repeat.
+     * @param {number} [n=1] The number of times to repeat the string.
+     * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
+     * @returns {string} Returns the repeated string.
+     * @example
+     *
+     * _.repeat('*', 3);
+     * // => '***'
+     *
+     * _.repeat('abc', 2);
+     * // => 'abcabc'
+     *
+     * _.repeat('abc', 0);
+     * // => ''
+     */
+    function repeat(string, n, guard) {
+      if ((guard ? isIterateeCall(string, n, guard) : n === undefined)) {
+        n = 1;
+      } else {
+        n = toInteger(n);
+      }
+      return baseRepeat(toString(string), n);
+    }
+
+    /**
+     * Replaces matches for `pattern` in `string` with `replacement`.
+     *
+     * **Note:** This method is based on
+     * [`String#replace`](https://mdn.io/String/replace).
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category String
+     * @param {string} [string=''] The string to modify.
+     * @param {RegExp|string} pattern The pattern to replace.
+     * @param {Function|string} replacement The match replacement.
+     * @returns {string} Returns the modified string.
+     * @example
+     *
+     * _.replace('Hi Fred', 'Fred', 'Barney');
+     * // => 'Hi Barney'
+     */
+    function replace() {
+      var args = arguments,
+          string = toString(args[0]);
+
+      return args.length < 3 ? string : string.replace(args[1], args[2]);
+    }
+
+    /**
+     * Converts `string` to
+     * [snake case](https://en.wikipedia.org/wiki/Snake_case).
+     *
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category String
+     * @param {string} [string=''] The string to convert.
+     * @returns {string} Returns the snake cased string.
+     * @example
+     *
+     * _.snakeCase('Foo Bar');
+     * // => 'foo_bar'
+     *
+     * _.snakeCase('fooBar');
+     * // => 'foo_bar'
+     *
+     * _.snakeCase('--FOO-BAR--');
+     * // => 'foo_bar'
+     */
+    var snakeCase = createCompounder(function(result, word, index) {
+      return result + (index ? '_' : '') + word.toLowerCase();
+    });
+
+    /**
+     * Splits `string` by `separator`.
+     *
+     * **Note:** This method is based on
+     * [`String#split`](https://mdn.io/String/split).
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category String
+     * @param {string} [string=''] The string to split.
+     * @param {RegExp|string} separator The separator pattern to split by.
+     * @param {number} [limit] The length to truncate results to.
+     * @returns {Array} Returns the string segments.
+     * @example
+     *
+     * _.split('a-b-c', '-', 2);
+     * // => ['a', 'b']
+     */
+    function split(string, separator, limit) {
+      if (limit && typeof limit != 'number' && isIterateeCall(string, separator, limit)) {
+        separator = limit = undefined;
+      }
+      limit = limit === undefined ? MAX_ARRAY_LENGTH : limit >>> 0;
+      if (!limit) {
+        return [];
+      }
+      string = toString(string);
+      if (string && (
+            typeof separator == 'string' ||
+            (separator != null && !isRegExp(separator))
+          )) {
+        separator = baseToString(separator);
+        if (!separator && hasUnicode(string)) {
+          return castSlice(stringToArray(string), 0, limit);
+        }
+      }
+      return string.split(separator, limit);
+    }
+
+    /**
+     * Converts `string` to
+     * [start case](https://en.wikipedia.org/wiki/Letter_case#Stylistic_or_specialised_usage).
+     *
+     * @static
+     * @memberOf _
+     * @since 3.1.0
+     * @category String
+     * @param {string} [string=''] The string to convert.
+     * @returns {string} Returns the start cased string.
+     * @example
+     *
+     * _.startCase('--foo-bar--');
+     * // => 'Foo Bar'
+     *
+     * _.startCase('fooBar');
+     * // => 'Foo Bar'
+     *
+     * _.startCase('__FOO_BAR__');
+     * // => 'FOO BAR'
+     */
+    var startCase = createCompounder(function(result, word, index) {
+      return result + (index ? ' ' : '') + upperFirst(word);
+    });
+
+    /**
+     * Checks if `string` starts with the given target string.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category String
+     * @param {string} [string=''] The string to inspect.
+     * @param {string} [target] The string to search for.
+     * @param {number} [position=0] The position to search from.
+     * @returns {boolean} Returns `true` if `string` starts with `target`,
+     *  else `false`.
+     * @example
+     *
+     * _.startsWith('abc', 'a');
+     * // => true
+     *
+     * _.startsWith('abc', 'b');
+     * // => false
      *
-     * // using the `imports` option to import jQuery
-     * var list = '<% jq.each(people, function(name) { %><li><%- name %></li><% }); %>';
-     * _.template(list, { 'people': ['fred', 'barney'] }, { 'imports': { 'jq': jQuery } });
+     * _.startsWith('abc', 'b', 1);
+     * // => true
+     */
+    function startsWith(string, target, position) {
+      string = toString(string);
+      position = position == null
+        ? 0
+        : baseClamp(toInteger(position), 0, string.length);
+
+      target = baseToString(target);
+      return string.slice(position, position + target.length) == target;
+    }
+
+    /**
+     * Creates a compiled template function that can interpolate data properties
+     * in "interpolate" delimiters, HTML-escape interpolated data properties in
+     * "escape" delimiters, and execute JavaScript in "evaluate" delimiters. Data
+     * properties may be accessed as free variables in the template. If a setting
+     * object is given, it takes precedence over `_.templateSettings` values.
+     *
+     * **Note:** In the development build `_.template` utilizes
+     * [sourceURLs](http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/#toc-sourceurl)
+     * for easier debugging.
+     *
+     * For more information on precompiling templates see
+     * [lodash's custom builds documentation](https://lodash.com/custom-builds).
+     *
+     * For more information on Chrome extension sandboxes see
+     * [Chrome's extensions documentation](https://developer.chrome.com/extensions/sandboxingEval).
+     *
+     * @static
+     * @since 0.1.0
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The template string.
+     * @param {Object} [options={}] The options object.
+     * @param {RegExp} [options.escape=_.templateSettings.escape]
+     *  The HTML "escape" delimiter.
+     * @param {RegExp} [options.evaluate=_.templateSettings.evaluate]
+     *  The "evaluate" delimiter.
+     * @param {Object} [options.imports=_.templateSettings.imports]
+     *  An object to import into the template as free variables.
+     * @param {RegExp} [options.interpolate=_.templateSettings.interpolate]
+     *  The "interpolate" delimiter.
+     * @param {string} [options.sourceURL='lodash.templateSources[n]']
+     *  The sourceURL of the compiled template.
+     * @param {string} [options.variable='obj']
+     *  The data object variable name.
+     * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
+     * @returns {Function} Returns the compiled template function.
+     * @example
+     *
+     * // Use the "interpolate" delimiter to create a compiled template.
+     * var compiled = _.template('hello <%= user %>!');
+     * compiled({ 'user': 'fred' });
+     * // => 'hello fred!'
+     *
+     * // Use the HTML "escape" delimiter to escape data property values.
+     * var compiled = _.template('<b><%- value %></b>');
+     * compiled({ 'value': '<script>' });
+     * // => '<b>&lt;script&gt;</b>'
+     *
+     * // Use the "evaluate" delimiter to execute JavaScript and generate HTML.
+     * var compiled = _.template('<% _.forEach(users, function(user) { %><li><%- user %></li><% }); %>');
+     * compiled({ 'users': ['fred', 'barney'] });
      * // => '<li>fred</li><li>barney</li>'
      *
-     * // using the `sourceURL` option to specify a custom sourceURL for the template
-     * var compiled = _.template('hello <%= name %>', null, { 'sourceURL': '/basic/greeting.jst' });
+     * // Use the internal `print` function in "evaluate" delimiters.
+     * var compiled = _.template('<% print("hello " + user); %>!');
+     * compiled({ 'user': 'barney' });
+     * // => 'hello barney!'
+     *
+     * // Use the ES template literal delimiter as an "interpolate" delimiter.
+     * // Disable support by replacing the "interpolate" delimiter.
+     * var compiled = _.template('hello ${ user }!');
+     * compiled({ 'user': 'pebbles' });
+     * // => 'hello pebbles!'
+     *
+     * // Use backslashes to treat delimiters as plain text.
+     * var compiled = _.template('<%= "\\<%- value %\\>" %>');
+     * compiled({ 'value': 'ignored' });
+     * // => '<%- value %>'
+     *
+     * // Use the `imports` option to import `jQuery` as `jq`.
+     * var text = '<% jq.each(users, function(user) { %><li><%- user %></li><% }); %>';
+     * var compiled = _.template(text, { 'imports': { 'jq': jQuery } });
+     * compiled({ 'users': ['fred', 'barney'] });
+     * // => '<li>fred</li><li>barney</li>'
+     *
+     * // Use the `sourceURL` option to specify a custom sourceURL for the template.
+     * var compiled = _.template('hello <%= user %>!', { 'sourceURL': '/basic/greeting.jst' });
      * compiled(data);
-     * // => find the source of "greeting.jst" under the Sources tab or Resources panel of the web inspector
+     * // => Find the source of "greeting.jst" under the Sources tab or Resources panel of the web inspector.
      *
-     * // using the `variable` option to ensure a with-statement isn't used in the compiled template
-     * var compiled = _.template('hi <%= data.name %>!', null, { 'variable': 'data' });
+     * // Use the `variable` option to ensure a with-statement isn't used in the compiled template.
+     * var compiled = _.template('hi <%= data.user %>!', { 'variable': 'data' });
      * compiled.source;
      * // => function(data) {
-     *   var __t, __p = '', __e = _.escape;
-     *   __p += 'hi ' + ((__t = ( data.name )) == null ? '' : __t) + '!';
-     *   return __p;
-     * }
+     * //   var __t, __p = '';
+     * //   __p += 'hi ' + ((__t = ( data.user )) == null ? '' : __t) + '!';
+     * //   return __p;
+     * // }
+     *
+     * // Use custom template delimiters.
+     * _.templateSettings.interpolate = /{{([\s\S]+?)}}/g;
+     * var compiled = _.template('hello {{ user }}!');
+     * compiled({ 'user': 'mustache' });
+     * // => 'hello mustache!'
      *
-     * // using the `source` property to inline compiled templates for meaningful
-     * // line numbers in error messages and a stack trace
-     * fs.writeFileSync(path.join(cwd, 'jst.js'), '\
+     * // Use the `source` property to inline compiled templates for meaningful
+     * // line numbers in error messages and stack traces.
+     * fs.writeFileSync(path.join(process.cwd(), 'jst.js'), '\
      *   var JST = {\
      *     "main": ' + _.template(mainText).source + '\
      *   };\
      * ');
      */
-    function template(text, data, options) {
-      // based on John Resig's `tmpl` implementation
-      // http://ejohn.org/blog/javascript-micro-templating/
-      // and Laura Doktorova's doT.js
-      // https://github.com/olado/doT
+    function template(string, options, guard) {
+      // Based on John Resig's `tmpl` implementation
+      // (http://ejohn.org/blog/javascript-micro-templating/)
+      // and Laura Doktorova's doT.js (https://github.com/olado/doT).
       var settings = lodash.templateSettings;
-      text = String(text || '');
 
-      // avoid missing dependencies when `iteratorTemplate` is not defined
-      options = iteratorTemplate ? defaults({}, options, settings) : settings;
+      if (guard && isIterateeCall(string, options, guard)) {
+        options = undefined;
+      }
+      string = toString(string);
+      options = assignInWith({}, options, settings, customDefaultsAssignIn);
 
-      var imports = iteratorTemplate && defaults({}, options.imports, settings.imports),
-          importsKeys = iteratorTemplate ? keys(imports) : ['_'],
-          importsValues = iteratorTemplate ? values(imports) : [lodash];
+      var imports = assignInWith({}, options.imports, settings.imports, customDefaultsAssignIn),
+          importsKeys = keys(imports),
+          importsValues = baseValues(imports, importsKeys);
 
-      var isEvaluating,
+      var isEscaping,
+          isEvaluating,
           index = 0,
           interpolate = options.interpolate || reNoMatch,
           source = "__p += '";
 
-      // compile the regexp to match each delimiter
+      // Compile the regexp to match each delimiter.
       var reDelimiters = RegExp(
         (options.escape || reNoMatch).source + '|' +
         interpolate.source + '|' +
@@ -6613,14 +14865,25 @@
         (options.evaluate || reNoMatch).source + '|$'
       , 'g');
 
-      text.replace(reDelimiters, function(match, escapeValue, interpolateValue, esTemplateValue, evaluateValue, offset) {
+      // Use a sourceURL for easier debugging.
+      // The sourceURL gets injected into the source that's eval-ed, so be careful
+      // to normalize all kinds of whitespace, so e.g. newlines (and unicode versions of it) can't sneak in
+      // and escape the comment, thus injecting code that gets evaled.
+      var sourceURL = '//# sourceURL=' +
+        (hasOwnProperty.call(options, 'sourceURL')
+          ? (options.sourceURL + '').replace(/\s/g, ' ')
+          : ('lodash.templateSources[' + (++templateCounter) + ']')
+        ) + '\n';
+
+      string.replace(reDelimiters, function(match, escapeValue, interpolateValue, esTemplateValue, evaluateValue, offset) {
         interpolateValue || (interpolateValue = esTemplateValue);
 
-        // escape characters that cannot be included in string literals
-        source += text.slice(index, offset).replace(reUnescapedString, escapeStringChar);
+        // Escape characters that can't be included in string literals.
+        source += string.slice(index, offset).replace(reUnescapedString, escapeStringChar);
 
-        // replace delimiters with snippets
+        // Replace delimiters with snippets.
         if (escapeValue) {
+          isEscaping = true;
           source += "' +\n__e(" + escapeValue + ") +\n'";
         }
         if (evaluateValue) {
@@ -6632,31 +14895,41 @@
         }
         index = offset + match.length;
 
-        // the JS engine embedded in Adobe products requires returning the `match`
-        // string in order to produce the correct `offset` value
+        // The JS engine embedded in Adobe products needs `match` returned in
+        // order to produce the correct `offset` value.
         return match;
       });
 
       source += "';\n";
 
-      // if `variable` is not specified, wrap a with-statement around the generated
-      // code to add the data object to the top of the scope chain
-      var variable = options.variable,
-          hasVariable = variable;
-
-      if (!hasVariable) {
-        variable = 'obj';
-        source = 'with (' + variable + ') {\n' + source + '\n}\n';
+      // If `variable` is not specified wrap a with-statement around the generated
+      // code to add the data object to the top of the scope chain.
+      var variable = hasOwnProperty.call(options, 'variable') && options.variable;
+      if (!variable) {
+        source = 'with (obj) {\n' + source + '\n}\n';
+      }
+      // Throw an error if a forbidden character was found in `variable`, to prevent
+      // potential command injection attacks.
+      else if (reForbiddenIdentifierChars.test(variable)) {
+        throw new Error(INVALID_TEMPL_VAR_ERROR_TEXT);
       }
-      // cleanup code by stripping empty strings
+
+      // Cleanup code by stripping empty strings.
       source = (isEvaluating ? source.replace(reEmptyStringLeading, '') : source)
         .replace(reEmptyStringMiddle, '$1')
         .replace(reEmptyStringTrailing, '$1;');
 
-      // frame code as the function body
-      source = 'function(' + variable + ') {\n' +
-        (hasVariable ? '' : variable + ' || (' + variable + ' = {});\n') +
-        "var __t, __p = '', __e = _.escape" +
+      // Frame code as the function body.
+      source = 'function(' + (variable || 'obj') + ') {\n' +
+        (variable
+          ? ''
+          : 'obj || (obj = {});\n'
+        ) +
+        "var __t, __p = ''" +
+        (isEscaping
+           ? ', __e = _.escape'
+           : ''
+        ) +
         (isEvaluating
           ? ', __j = Array.prototype.join;\n' +
             "function print() { __p += __j.call(arguments, '') }\n"
@@ -6665,87 +14938,1323 @@
         source +
         'return __p\n}';
 
-      // Use a sourceURL for easier debugging.
-      // http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/#toc-sourceurl
-      var sourceURL = '\n/*\n//# sourceURL=' + (options.sourceURL || '/lodash/template/source[' + (templateCounter++) + ']') + '\n*/';
+      var result = attempt(function() {
+        return Function(importsKeys, sourceURL + 'return ' + source)
+          .apply(undefined, importsValues);
+      });
+
+      // Provide the compiled function's source by its `toString` method or
+      // the `source` property as a convenience for inlining compiled templates.
+      result.source = source;
+      if (isError(result)) {
+        throw result;
+      }
+      return result;
+    }
+
+    /**
+     * Converts `string`, as a whole, to lower case just like
+     * [String#toLowerCase](https://mdn.io/toLowerCase).
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category String
+     * @param {string} [string=''] The string to convert.
+     * @returns {string} Returns the lower cased string.
+     * @example
+     *
+     * _.toLower('--Foo-Bar--');
+     * // => '--foo-bar--'
+     *
+     * _.toLower('fooBar');
+     * // => 'foobar'
+     *
+     * _.toLower('__FOO_BAR__');
+     * // => '__foo_bar__'
+     */
+    function toLower(value) {
+      return toString(value).toLowerCase();
+    }
+
+    /**
+     * Converts `string`, as a whole, to upper case just like
+     * [String#toUpperCase](https://mdn.io/toUpperCase).
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category String
+     * @param {string} [string=''] The string to convert.
+     * @returns {string} Returns the upper cased string.
+     * @example
+     *
+     * _.toUpper('--foo-bar--');
+     * // => '--FOO-BAR--'
+     *
+     * _.toUpper('fooBar');
+     * // => 'FOOBAR'
+     *
+     * _.toUpper('__foo_bar__');
+     * // => '__FOO_BAR__'
+     */
+    function toUpper(value) {
+      return toString(value).toUpperCase();
+    }
+
+    /**
+     * Removes leading and trailing whitespace or specified characters from `string`.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category String
+     * @param {string} [string=''] The string to trim.
+     * @param {string} [chars=whitespace] The characters to trim.
+     * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
+     * @returns {string} Returns the trimmed string.
+     * @example
+     *
+     * _.trim('  abc  ');
+     * // => 'abc'
+     *
+     * _.trim('-_-abc-_-', '_-');
+     * // => 'abc'
+     *
+     * _.map(['  foo  ', '  bar  '], _.trim);
+     * // => ['foo', 'bar']
+     */
+    function trim(string, chars, guard) {
+      string = toString(string);
+      if (string && (guard || chars === undefined)) {
+        return baseTrim(string);
+      }
+      if (!string || !(chars = baseToString(chars))) {
+        return string;
+      }
+      var strSymbols = stringToArray(string),
+          chrSymbols = stringToArray(chars),
+          start = charsStartIndex(strSymbols, chrSymbols),
+          end = charsEndIndex(strSymbols, chrSymbols) + 1;
+
+      return castSlice(strSymbols, start, end).join('');
+    }
+
+    /**
+     * Removes trailing whitespace or specified characters from `string`.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category String
+     * @param {string} [string=''] The string to trim.
+     * @param {string} [chars=whitespace] The characters to trim.
+     * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
+     * @returns {string} Returns the trimmed string.
+     * @example
+     *
+     * _.trimEnd('  abc  ');
+     * // => '  abc'
+     *
+     * _.trimEnd('-_-abc-_-', '_-');
+     * // => '-_-abc'
+     */
+    function trimEnd(string, chars, guard) {
+      string = toString(string);
+      if (string && (guard || chars === undefined)) {
+        return string.slice(0, trimmedEndIndex(string) + 1);
+      }
+      if (!string || !(chars = baseToString(chars))) {
+        return string;
+      }
+      var strSymbols = stringToArray(string),
+          end = charsEndIndex(strSymbols, stringToArray(chars)) + 1;
+
+      return castSlice(strSymbols, 0, end).join('');
+    }
+
+    /**
+     * Removes leading whitespace or specified characters from `string`.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category String
+     * @param {string} [string=''] The string to trim.
+     * @param {string} [chars=whitespace] The characters to trim.
+     * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
+     * @returns {string} Returns the trimmed string.
+     * @example
+     *
+     * _.trimStart('  abc  ');
+     * // => 'abc  '
+     *
+     * _.trimStart('-_-abc-_-', '_-');
+     * // => 'abc-_-'
+     */
+    function trimStart(string, chars, guard) {
+      string = toString(string);
+      if (string && (guard || chars === undefined)) {
+        return string.replace(reTrimStart, '');
+      }
+      if (!string || !(chars = baseToString(chars))) {
+        return string;
+      }
+      var strSymbols = stringToArray(string),
+          start = charsStartIndex(strSymbols, stringToArray(chars));
+
+      return castSlice(strSymbols, start).join('');
+    }
+
+    /**
+     * Truncates `string` if it's longer than the given maximum string length.
+     * The last characters of the truncated string are replaced with the omission
+     * string which defaults to "...".
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category String
+     * @param {string} [string=''] The string to truncate.
+     * @param {Object} [options={}] The options object.
+     * @param {number} [options.length=30] The maximum string length.
+     * @param {string} [options.omission='...'] The string to indicate text is omitted.
+     * @param {RegExp|string} [options.separator] The separator pattern to truncate to.
+     * @returns {string} Returns the truncated string.
+     * @example
+     *
+     * _.truncate('hi-diddly-ho there, neighborino');
+     * // => 'hi-diddly-ho there, neighbo...'
+     *
+     * _.truncate('hi-diddly-ho there, neighborino', {
+     *   'length': 24,
+     *   'separator': ' '
+     * });
+     * // => 'hi-diddly-ho there,...'
+     *
+     * _.truncate('hi-diddly-ho there, neighborino', {
+     *   'length': 24,
+     *   'separator': /,? +/
+     * });
+     * // => 'hi-diddly-ho there...'
+     *
+     * _.truncate('hi-diddly-ho there, neighborino', {
+     *   'omission': ' [...]'
+     * });
+     * // => 'hi-diddly-ho there, neig [...]'
+     */
+    function truncate(string, options) {
+      var length = DEFAULT_TRUNC_LENGTH,
+          omission = DEFAULT_TRUNC_OMISSION;
+
+      if (isObject(options)) {
+        var separator = 'separator' in options ? options.separator : separator;
+        length = 'length' in options ? toInteger(options.length) : length;
+        omission = 'omission' in options ? baseToString(options.omission) : omission;
+      }
+      string = toString(string);
+
+      var strLength = string.length;
+      if (hasUnicode(string)) {
+        var strSymbols = stringToArray(string);
+        strLength = strSymbols.length;
+      }
+      if (length >= strLength) {
+        return string;
+      }
+      var end = length - stringSize(omission);
+      if (end < 1) {
+        return omission;
+      }
+      var result = strSymbols
+        ? castSlice(strSymbols, 0, end).join('')
+        : string.slice(0, end);
+
+      if (separator === undefined) {
+        return result + omission;
+      }
+      if (strSymbols) {
+        end += (result.length - end);
+      }
+      if (isRegExp(separator)) {
+        if (string.slice(end).search(separator)) {
+          var match,
+              substring = result;
+
+          if (!separator.global) {
+            separator = RegExp(separator.source, toString(reFlags.exec(separator)) + 'g');
+          }
+          separator.lastIndex = 0;
+          while ((match = separator.exec(substring))) {
+            var newEnd = match.index;
+          }
+          result = result.slice(0, newEnd === undefined ? end : newEnd);
+        }
+      } else if (string.indexOf(baseToString(separator), end) != end) {
+        var index = result.lastIndexOf(separator);
+        if (index > -1) {
+          result = result.slice(0, index);
+        }
+      }
+      return result + omission;
+    }
 
+    /**
+     * The inverse of `_.escape`; this method converts the HTML entities
+     * `&amp;`, `&lt;`, `&gt;`, `&quot;`, and `&#39;` in `string` to
+     * their corresponding characters.
+     *
+     * **Note:** No other HTML entities are unescaped. To unescape additional
+     * HTML entities use a third-party library like [_he_](https://mths.be/he).
+     *
+     * @static
+     * @memberOf _
+     * @since 0.6.0
+     * @category String
+     * @param {string} [string=''] The string to unescape.
+     * @returns {string} Returns the unescaped string.
+     * @example
+     *
+     * _.unescape('fred, barney, &amp; pebbles');
+     * // => 'fred, barney, & pebbles'
+     */
+    function unescape(string) {
+      string = toString(string);
+      return (string && reHasEscapedHtml.test(string))
+        ? string.replace(reEscapedHtml, unescapeHtmlChar)
+        : string;
+    }
+
+    /**
+     * Converts `string`, as space separated words, to upper case.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category String
+     * @param {string} [string=''] The string to convert.
+     * @returns {string} Returns the upper cased string.
+     * @example
+     *
+     * _.upperCase('--foo-bar');
+     * // => 'FOO BAR'
+     *
+     * _.upperCase('fooBar');
+     * // => 'FOO BAR'
+     *
+     * _.upperCase('__foo_bar__');
+     * // => 'FOO BAR'
+     */
+    var upperCase = createCompounder(function(result, word, index) {
+      return result + (index ? ' ' : '') + word.toUpperCase();
+    });
+
+    /**
+     * Converts the first character of `string` to upper case.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category String
+     * @param {string} [string=''] The string to convert.
+     * @returns {string} Returns the converted string.
+     * @example
+     *
+     * _.upperFirst('fred');
+     * // => 'Fred'
+     *
+     * _.upperFirst('FRED');
+     * // => 'FRED'
+     */
+    var upperFirst = createCaseFirst('toUpperCase');
+
+    /**
+     * Splits `string` into an array of its words.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category String
+     * @param {string} [string=''] The string to inspect.
+     * @param {RegExp|string} [pattern] The pattern to match words.
+     * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
+     * @returns {Array} Returns the words of `string`.
+     * @example
+     *
+     * _.words('fred, barney, & pebbles');
+     * // => ['fred', 'barney', 'pebbles']
+     *
+     * _.words('fred, barney, & pebbles', /[^, ]+/g);
+     * // => ['fred', 'barney', '&', 'pebbles']
+     */
+    function words(string, pattern, guard) {
+      string = toString(string);
+      pattern = guard ? undefined : pattern;
+
+      if (pattern === undefined) {
+        return hasUnicodeWord(string) ? unicodeWords(string) : asciiWords(string);
+      }
+      return string.match(pattern) || [];
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Attempts to invoke `func`, returning either the result or the caught error
+     * object. Any additional arguments are provided to `func` when it's invoked.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category Util
+     * @param {Function} func The function to attempt.
+     * @param {...*} [args] The arguments to invoke `func` with.
+     * @returns {*} Returns the `func` result or error object.
+     * @example
+     *
+     * // Avoid throwing errors for invalid selectors.
+     * var elements = _.attempt(function(selector) {
+     *   return document.querySelectorAll(selector);
+     * }, '>_>');
+     *
+     * if (_.isError(elements)) {
+     *   elements = [];
+     * }
+     */
+    var attempt = baseRest(function(func, args) {
       try {
-        var result = Function(importsKeys, 'return ' + source + sourceURL).apply(undefined, importsValues);
-      } catch(e) {
-        e.source = source;
-        throw e;
+        return apply(func, undefined, args);
+      } catch (e) {
+        return isError(e) ? e : new Error(e);
       }
-      if (data) {
-        return result(data);
+    });
+
+    /**
+     * Binds methods of an object to the object itself, overwriting the existing
+     * method.
+     *
+     * **Note:** This method doesn't set the "length" property of bound functions.
+     *
+     * @static
+     * @since 0.1.0
+     * @memberOf _
+     * @category Util
+     * @param {Object} object The object to bind and assign the bound methods to.
+     * @param {...(string|string[])} methodNames The object method names to bind.
+     * @returns {Object} Returns `object`.
+     * @example
+     *
+     * var view = {
+     *   'label': 'docs',
+     *   'click': function() {
+     *     console.log('clicked ' + this.label);
+     *   }
+     * };
+     *
+     * _.bindAll(view, ['click']);
+     * jQuery(element).on('click', view.click);
+     * // => Logs 'clicked docs' when clicked.
+     */
+    var bindAll = flatRest(function(object, methodNames) {
+      arrayEach(methodNames, function(key) {
+        key = toKey(key);
+        baseAssignValue(object, key, bind(object[key], object));
+      });
+      return object;
+    });
+
+    /**
+     * Creates a function that iterates over `pairs` and invokes the corresponding
+     * function of the first predicate to return truthy. The predicate-function
+     * pairs are invoked with the `this` binding and arguments of the created
+     * function.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Util
+     * @param {Array} pairs The predicate-function pairs.
+     * @returns {Function} Returns the new composite function.
+     * @example
+     *
+     * var func = _.cond([
+     *   [_.matches({ 'a': 1 }),           _.constant('matches A')],
+     *   [_.conforms({ 'b': _.isNumber }), _.constant('matches B')],
+     *   [_.stubTrue,                      _.constant('no match')]
+     * ]);
+     *
+     * func({ 'a': 1, 'b': 2 });
+     * // => 'matches A'
+     *
+     * func({ 'a': 0, 'b': 1 });
+     * // => 'matches B'
+     *
+     * func({ 'a': '1', 'b': '2' });
+     * // => 'no match'
+     */
+    function cond(pairs) {
+      var length = pairs == null ? 0 : pairs.length,
+          toIteratee = getIteratee();
+
+      pairs = !length ? [] : arrayMap(pairs, function(pair) {
+        if (typeof pair[1] != 'function') {
+          throw new TypeError(FUNC_ERROR_TEXT);
+        }
+        return [toIteratee(pair[0]), pair[1]];
+      });
+
+      return baseRest(function(args) {
+        var index = -1;
+        while (++index < length) {
+          var pair = pairs[index];
+          if (apply(pair[0], this, args)) {
+            return apply(pair[1], this, args);
+          }
+        }
+      });
+    }
+
+    /**
+     * Creates a function that invokes the predicate properties of `source` with
+     * the corresponding property values of a given object, returning `true` if
+     * all predicates return truthy, else `false`.
+     *
+     * **Note:** The created function is equivalent to `_.conformsTo` with
+     * `source` partially applied.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Util
+     * @param {Object} source The object of property predicates to conform to.
+     * @returns {Function} Returns the new spec function.
+     * @example
+     *
+     * var objects = [
+     *   { 'a': 2, 'b': 1 },
+     *   { 'a': 1, 'b': 2 }
+     * ];
+     *
+     * _.filter(objects, _.conforms({ 'b': function(n) { return n > 1; } }));
+     * // => [{ 'a': 1, 'b': 2 }]
+     */
+    function conforms(source) {
+      return baseConforms(baseClone(source, CLONE_DEEP_FLAG));
+    }
+
+    /**
+     * Creates a function that returns `value`.
+     *
+     * @static
+     * @memberOf _
+     * @since 2.4.0
+     * @category Util
+     * @param {*} value The value to return from the new function.
+     * @returns {Function} Returns the new constant function.
+     * @example
+     *
+     * var objects = _.times(2, _.constant({ 'a': 1 }));
+     *
+     * console.log(objects);
+     * // => [{ 'a': 1 }, { 'a': 1 }]
+     *
+     * console.log(objects[0] === objects[1]);
+     * // => true
+     */
+    function constant(value) {
+      return function() {
+        return value;
+      };
+    }
+
+    /**
+     * Checks `value` to determine whether a default value should be returned in
+     * its place. The `defaultValue` is returned if `value` is `NaN`, `null`,
+     * or `undefined`.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.14.0
+     * @category Util
+     * @param {*} value The value to check.
+     * @param {*} defaultValue The default value.
+     * @returns {*} Returns the resolved value.
+     * @example
+     *
+     * _.defaultTo(1, 10);
+     * // => 1
+     *
+     * _.defaultTo(undefined, 10);
+     * // => 10
+     */
+    function defaultTo(value, defaultValue) {
+      return (value == null || value !== value) ? defaultValue : value;
+    }
+
+    /**
+     * Creates a function that returns the result of invoking the given functions
+     * with the `this` binding of the created function, where each successive
+     * invocation is supplied the return value of the previous.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category Util
+     * @param {...(Function|Function[])} [funcs] The functions to invoke.
+     * @returns {Function} Returns the new composite function.
+     * @see _.flowRight
+     * @example
+     *
+     * function square(n) {
+     *   return n * n;
+     * }
+     *
+     * var addSquare = _.flow([_.add, square]);
+     * addSquare(1, 2);
+     * // => 9
+     */
+    var flow = createFlow();
+
+    /**
+     * This method is like `_.flow` except that it creates a function that
+     * invokes the given functions from right to left.
+     *
+     * @static
+     * @since 3.0.0
+     * @memberOf _
+     * @category Util
+     * @param {...(Function|Function[])} [funcs] The functions to invoke.
+     * @returns {Function} Returns the new composite function.
+     * @see _.flow
+     * @example
+     *
+     * function square(n) {
+     *   return n * n;
+     * }
+     *
+     * var addSquare = _.flowRight([square, _.add]);
+     * addSquare(1, 2);
+     * // => 9
+     */
+    var flowRight = createFlow(true);
+
+    /**
+     * This method returns the first argument it receives.
+     *
+     * @static
+     * @since 0.1.0
+     * @memberOf _
+     * @category Util
+     * @param {*} value Any value.
+     * @returns {*} Returns `value`.
+     * @example
+     *
+     * var object = { 'a': 1 };
+     *
+     * console.log(_.identity(object) === object);
+     * // => true
+     */
+    function identity(value) {
+      return value;
+    }
+
+    /**
+     * Creates a function that invokes `func` with the arguments of the created
+     * function. If `func` is a property name, the created function returns the
+     * property value for a given element. If `func` is an array or object, the
+     * created function returns `true` for elements that contain the equivalent
+     * source properties, otherwise it returns `false`.
+     *
+     * @static
+     * @since 4.0.0
+     * @memberOf _
+     * @category Util
+     * @param {*} [func=_.identity] The value to convert to a callback.
+     * @returns {Function} Returns the callback.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney', 'age': 36, 'active': true },
+     *   { 'user': 'fred',   'age': 40, 'active': false }
+     * ];
+     *
+     * // The `_.matches` iteratee shorthand.
+     * _.filter(users, _.iteratee({ 'user': 'barney', 'active': true }));
+     * // => [{ 'user': 'barney', 'age': 36, 'active': true }]
+     *
+     * // The `_.matchesProperty` iteratee shorthand.
+     * _.filter(users, _.iteratee(['user', 'fred']));
+     * // => [{ 'user': 'fred', 'age': 40 }]
+     *
+     * // The `_.property` iteratee shorthand.
+     * _.map(users, _.iteratee('user'));
+     * // => ['barney', 'fred']
+     *
+     * // Create custom iteratee shorthands.
+     * _.iteratee = _.wrap(_.iteratee, function(iteratee, func) {
+     *   return !_.isRegExp(func) ? iteratee(func) : function(string) {
+     *     return func.test(string);
+     *   };
+     * });
+     *
+     * _.filter(['abc', 'def'], /ef/);
+     * // => ['def']
+     */
+    function iteratee(func) {
+      return baseIteratee(typeof func == 'function' ? func : baseClone(func, CLONE_DEEP_FLAG));
+    }
+
+    /**
+     * Creates a function that performs a partial deep comparison between a given
+     * object and `source`, returning `true` if the given object has equivalent
+     * property values, else `false`.
+     *
+     * **Note:** The created function is equivalent to `_.isMatch` with `source`
+     * partially applied.
+     *
+     * Partial comparisons will match empty array and empty object `source`
+     * values against any array or object value, respectively. See `_.isEqual`
+     * for a list of supported value comparisons.
+     *
+     * **Note:** Multiple values can be checked by combining several matchers
+     * using `_.overSome`
+     *
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category Util
+     * @param {Object} source The object of property values to match.
+     * @returns {Function} Returns the new spec function.
+     * @example
+     *
+     * var objects = [
+     *   { 'a': 1, 'b': 2, 'c': 3 },
+     *   { 'a': 4, 'b': 5, 'c': 6 }
+     * ];
+     *
+     * _.filter(objects, _.matches({ 'a': 4, 'c': 6 }));
+     * // => [{ 'a': 4, 'b': 5, 'c': 6 }]
+     *
+     * // Checking for several possible values
+     * _.filter(objects, _.overSome([_.matches({ 'a': 1 }), _.matches({ 'a': 4 })]));
+     * // => [{ 'a': 1, 'b': 2, 'c': 3 }, { 'a': 4, 'b': 5, 'c': 6 }]
+     */
+    function matches(source) {
+      return baseMatches(baseClone(source, CLONE_DEEP_FLAG));
+    }
+
+    /**
+     * Creates a function that performs a partial deep comparison between the
+     * value at `path` of a given object to `srcValue`, returning `true` if the
+     * object value is equivalent, else `false`.
+     *
+     * **Note:** Partial comparisons will match empty array and empty object
+     * `srcValue` values against any array or object value, respectively. See
+     * `_.isEqual` for a list of supported value comparisons.
+     *
+     * **Note:** Multiple values can be checked by combining several matchers
+     * using `_.overSome`
+     *
+     * @static
+     * @memberOf _
+     * @since 3.2.0
+     * @category Util
+     * @param {Array|string} path The path of the property to get.
+     * @param {*} srcValue The value to match.
+     * @returns {Function} Returns the new spec function.
+     * @example
+     *
+     * var objects = [
+     *   { 'a': 1, 'b': 2, 'c': 3 },
+     *   { 'a': 4, 'b': 5, 'c': 6 }
+     * ];
+     *
+     * _.find(objects, _.matchesProperty('a', 4));
+     * // => { 'a': 4, 'b': 5, 'c': 6 }
+     *
+     * // Checking for several possible values
+     * _.filter(objects, _.overSome([_.matchesProperty('a', 1), _.matchesProperty('a', 4)]));
+     * // => [{ 'a': 1, 'b': 2, 'c': 3 }, { 'a': 4, 'b': 5, 'c': 6 }]
+     */
+    function matchesProperty(path, srcValue) {
+      return baseMatchesProperty(path, baseClone(srcValue, CLONE_DEEP_FLAG));
+    }
+
+    /**
+     * Creates a function that invokes the method at `path` of a given object.
+     * Any additional arguments are provided to the invoked method.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.7.0
+     * @category Util
+     * @param {Array|string} path The path of the method to invoke.
+     * @param {...*} [args] The arguments to invoke the method with.
+     * @returns {Function} Returns the new invoker function.
+     * @example
+     *
+     * var objects = [
+     *   { 'a': { 'b': _.constant(2) } },
+     *   { 'a': { 'b': _.constant(1) } }
+     * ];
+     *
+     * _.map(objects, _.method('a.b'));
+     * // => [2, 1]
+     *
+     * _.map(objects, _.method(['a', 'b']));
+     * // => [2, 1]
+     */
+    var method = baseRest(function(path, args) {
+      return function(object) {
+        return baseInvoke(object, path, args);
+      };
+    });
+
+    /**
+     * The opposite of `_.method`; this method creates a function that invokes
+     * the method at a given path of `object`. Any additional arguments are
+     * provided to the invoked method.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.7.0
+     * @category Util
+     * @param {Object} object The object to query.
+     * @param {...*} [args] The arguments to invoke the method with.
+     * @returns {Function} Returns the new invoker function.
+     * @example
+     *
+     * var array = _.times(3, _.constant),
+     *     object = { 'a': array, 'b': array, 'c': array };
+     *
+     * _.map(['a[2]', 'c[0]'], _.methodOf(object));
+     * // => [2, 0]
+     *
+     * _.map([['a', '2'], ['c', '0']], _.methodOf(object));
+     * // => [2, 0]
+     */
+    var methodOf = baseRest(function(object, args) {
+      return function(path) {
+        return baseInvoke(object, path, args);
+      };
+    });
+
+    /**
+     * Adds all own enumerable string keyed function properties of a source
+     * object to the destination object. If `object` is a function, then methods
+     * are added to its prototype as well.
+     *
+     * **Note:** Use `_.runInContext` to create a pristine `lodash` function to
+     * avoid conflicts caused by modifying the original.
+     *
+     * @static
+     * @since 0.1.0
+     * @memberOf _
+     * @category Util
+     * @param {Function|Object} [object=lodash] The destination object.
+     * @param {Object} source The object of functions to add.
+     * @param {Object} [options={}] The options object.
+     * @param {boolean} [options.chain=true] Specify whether mixins are chainable.
+     * @returns {Function|Object} Returns `object`.
+     * @example
+     *
+     * function vowels(string) {
+     *   return _.filter(string, function(v) {
+     *     return /[aeiou]/i.test(v);
+     *   });
+     * }
+     *
+     * _.mixin({ 'vowels': vowels });
+     * _.vowels('fred');
+     * // => ['e']
+     *
+     * _('fred').vowels().value();
+     * // => ['e']
+     *
+     * _.mixin({ 'vowels': vowels }, { 'chain': false });
+     * _('fred').vowels();
+     * // => ['e']
+     */
+    function mixin(object, source, options) {
+      var props = keys(source),
+          methodNames = baseFunctions(source, props);
+
+      if (options == null &&
+          !(isObject(source) && (methodNames.length || !props.length))) {
+        options = source;
+        source = object;
+        object = this;
+        methodNames = baseFunctions(source, keys(source));
       }
-      // provide the compiled function's source by its `toString` method, in
-      // supported environments, or the `source` property as a convenience for
-      // inlining compiled templates during the build process
-      result.source = source;
-      return result;
+      var chain = !(isObject(options) && 'chain' in options) || !!options.chain,
+          isFunc = isFunction(object);
+
+      arrayEach(methodNames, function(methodName) {
+        var func = source[methodName];
+        object[methodName] = func;
+        if (isFunc) {
+          object.prototype[methodName] = function() {
+            var chainAll = this.__chain__;
+            if (chain || chainAll) {
+              var result = object(this.__wrapped__),
+                  actions = result.__actions__ = copyArray(this.__actions__);
+
+              actions.push({ 'func': func, 'args': arguments, 'thisArg': object });
+              result.__chain__ = chainAll;
+              return result;
+            }
+            return func.apply(object, arrayPush([this.value()], arguments));
+          };
+        }
+      });
+
+      return object;
+    }
+
+    /**
+     * Reverts the `_` variable to its previous value and returns a reference to
+     * the `lodash` function.
+     *
+     * @static
+     * @since 0.1.0
+     * @memberOf _
+     * @category Util
+     * @returns {Function} Returns the `lodash` function.
+     * @example
+     *
+     * var lodash = _.noConflict();
+     */
+    function noConflict() {
+      if (root._ === this) {
+        root._ = oldDash;
+      }
+      return this;
     }
 
     /**
-     * Executes the callback `n` times, returning an array of the results
-     * of each callback execution. The callback is bound to `thisArg` and invoked
-     * with one argument; (index).
+     * This method returns `undefined`.
      *
      * @static
      * @memberOf _
-     * @category Utilities
-     * @param {number} n The number of times to execute the callback.
-     * @param {Function} callback The function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns an array of the results of each `callback` execution.
+     * @since 2.3.0
+     * @category Util
      * @example
      *
-     * var diceRolls = _.times(3, _.partial(_.random, 1, 6));
-     * // => [3, 6, 4]
+     * _.times(2, _.noop);
+     * // => [undefined, undefined]
+     */
+    function noop() {
+      // No operation performed.
+    }
+
+    /**
+     * Creates a function that gets the argument at index `n`. If `n` is negative,
+     * the nth argument from the end is returned.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Util
+     * @param {number} [n=0] The index of the argument to return.
+     * @returns {Function} Returns the new pass-thru function.
+     * @example
      *
-     * _.times(3, function(n) { mage.castSpell(n); });
-     * // => calls `mage.castSpell(n)` three times, passing `n` of `0`, `1`, and `2` respectively
+     * var func = _.nthArg(1);
+     * func('a', 'b', 'c', 'd');
+     * // => 'b'
      *
-     * _.times(3, function(n) { this.cast(n); }, mage);
-     * // => also calls `mage.castSpell(n)` three times
+     * var func = _.nthArg(-2);
+     * func('a', 'b', 'c', 'd');
+     * // => 'c'
      */
-    function times(n, callback, thisArg) {
-      n = (n = +n) > -1 ? n : 0;
-      var index = -1,
-          result = Array(n);
+    function nthArg(n) {
+      n = toInteger(n);
+      return baseRest(function(args) {
+        return baseNth(args, n);
+      });
+    }
 
-      callback = baseCreateCallback(callback, thisArg, 1);
+    /**
+     * Creates a function that invokes `iteratees` with the arguments it receives
+     * and returns their results.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Util
+     * @param {...(Function|Function[])} [iteratees=[_.identity]]
+     *  The iteratees to invoke.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var func = _.over([Math.max, Math.min]);
+     *
+     * func(1, 2, 3, 4);
+     * // => [4, 1]
+     */
+    var over = createOver(arrayMap);
+
+    /**
+     * Creates a function that checks if **all** of the `predicates` return
+     * truthy when invoked with the arguments it receives.
+     *
+     * Following shorthands are possible for providing predicates.
+     * Pass an `Object` and it will be used as an parameter for `_.matches` to create the predicate.
+     * Pass an `Array` of parameters for `_.matchesProperty` and the predicate will be created using them.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Util
+     * @param {...(Function|Function[])} [predicates=[_.identity]]
+     *  The predicates to check.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var func = _.overEvery([Boolean, isFinite]);
+     *
+     * func('1');
+     * // => true
+     *
+     * func(null);
+     * // => false
+     *
+     * func(NaN);
+     * // => false
+     */
+    var overEvery = createOver(arrayEvery);
+
+    /**
+     * Creates a function that checks if **any** of the `predicates` return
+     * truthy when invoked with the arguments it receives.
+     *
+     * Following shorthands are possible for providing predicates.
+     * Pass an `Object` and it will be used as an parameter for `_.matches` to create the predicate.
+     * Pass an `Array` of parameters for `_.matchesProperty` and the predicate will be created using them.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Util
+     * @param {...(Function|Function[])} [predicates=[_.identity]]
+     *  The predicates to check.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var func = _.overSome([Boolean, isFinite]);
+     *
+     * func('1');
+     * // => true
+     *
+     * func(null);
+     * // => true
+     *
+     * func(NaN);
+     * // => false
+     *
+     * var matchesFunc = _.overSome([{ 'a': 1 }, { 'a': 2 }])
+     * var matchesPropertyFunc = _.overSome([['a', 1], ['a', 2]])
+     */
+    var overSome = createOver(arraySome);
+
+    /**
+     * Creates a function that returns the value at `path` of a given object.
+     *
+     * @static
+     * @memberOf _
+     * @since 2.4.0
+     * @category Util
+     * @param {Array|string} path The path of the property to get.
+     * @returns {Function} Returns the new accessor function.
+     * @example
+     *
+     * var objects = [
+     *   { 'a': { 'b': 2 } },
+     *   { 'a': { 'b': 1 } }
+     * ];
+     *
+     * _.map(objects, _.property('a.b'));
+     * // => [2, 1]
+     *
+     * _.map(_.sortBy(objects, _.property(['a', 'b'])), 'a.b');
+     * // => [1, 2]
+     */
+    function property(path) {
+      return isKey(path) ? baseProperty(toKey(path)) : basePropertyDeep(path);
+    }
+
+    /**
+     * The opposite of `_.property`; this method creates a function that returns
+     * the value at a given path of `object`.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.0.0
+     * @category Util
+     * @param {Object} object The object to query.
+     * @returns {Function} Returns the new accessor function.
+     * @example
+     *
+     * var array = [0, 1, 2],
+     *     object = { 'a': array, 'b': array, 'c': array };
+     *
+     * _.map(['a[2]', 'c[0]'], _.propertyOf(object));
+     * // => [2, 0]
+     *
+     * _.map([['a', '2'], ['c', '0']], _.propertyOf(object));
+     * // => [2, 0]
+     */
+    function propertyOf(object) {
+      return function(path) {
+        return object == null ? undefined : baseGet(object, path);
+      };
+    }
+
+    /**
+     * Creates an array of numbers (positive and/or negative) progressing from
+     * `start` up to, but not including, `end`. A step of `-1` is used if a negative
+     * `start` is specified without an `end` or `step`. If `end` is not specified,
+     * it's set to `start` with `start` then set to `0`.
+     *
+     * **Note:** JavaScript follows the IEEE-754 standard for resolving
+     * floating-point values which can produce unexpected results.
+     *
+     * @static
+     * @since 0.1.0
+     * @memberOf _
+     * @category Util
+     * @param {number} [start=0] The start of the range.
+     * @param {number} end The end of the range.
+     * @param {number} [step=1] The value to increment or decrement by.
+     * @returns {Array} Returns the range of numbers.
+     * @see _.inRange, _.rangeRight
+     * @example
+     *
+     * _.range(4);
+     * // => [0, 1, 2, 3]
+     *
+     * _.range(-4);
+     * // => [0, -1, -2, -3]
+     *
+     * _.range(1, 5);
+     * // => [1, 2, 3, 4]
+     *
+     * _.range(0, 20, 5);
+     * // => [0, 5, 10, 15]
+     *
+     * _.range(0, -4, -1);
+     * // => [0, -1, -2, -3]
+     *
+     * _.range(1, 4, 0);
+     * // => [1, 1, 1]
+     *
+     * _.range(0);
+     * // => []
+     */
+    var range = createRange();
+
+    /**
+     * This method is like `_.range` except that it populates values in
+     * descending order.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Util
+     * @param {number} [start=0] The start of the range.
+     * @param {number} end The end of the range.
+     * @param {number} [step=1] The value to increment or decrement by.
+     * @returns {Array} Returns the range of numbers.
+     * @see _.inRange, _.range
+     * @example
+     *
+     * _.rangeRight(4);
+     * // => [3, 2, 1, 0]
+     *
+     * _.rangeRight(-4);
+     * // => [-3, -2, -1, 0]
+     *
+     * _.rangeRight(1, 5);
+     * // => [4, 3, 2, 1]
+     *
+     * _.rangeRight(0, 20, 5);
+     * // => [15, 10, 5, 0]
+     *
+     * _.rangeRight(0, -4, -1);
+     * // => [-3, -2, -1, 0]
+     *
+     * _.rangeRight(1, 4, 0);
+     * // => [1, 1, 1]
+     *
+     * _.rangeRight(0);
+     * // => []
+     */
+    var rangeRight = createRange(true);
+
+    /**
+     * This method returns a new empty array.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.13.0
+     * @category Util
+     * @returns {Array} Returns the new empty array.
+     * @example
+     *
+     * var arrays = _.times(2, _.stubArray);
+     *
+     * console.log(arrays);
+     * // => [[], []]
+     *
+     * console.log(arrays[0] === arrays[1]);
+     * // => false
+     */
+    function stubArray() {
+      return [];
+    }
+
+    /**
+     * This method returns `false`.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.13.0
+     * @category Util
+     * @returns {boolean} Returns `false`.
+     * @example
+     *
+     * _.times(2, _.stubFalse);
+     * // => [false, false]
+     */
+    function stubFalse() {
+      return false;
+    }
+
+    /**
+     * This method returns a new empty object.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.13.0
+     * @category Util
+     * @returns {Object} Returns the new empty object.
+     * @example
+     *
+     * var objects = _.times(2, _.stubObject);
+     *
+     * console.log(objects);
+     * // => [{}, {}]
+     *
+     * console.log(objects[0] === objects[1]);
+     * // => false
+     */
+    function stubObject() {
+      return {};
+    }
+
+    /**
+     * This method returns an empty string.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.13.0
+     * @category Util
+     * @returns {string} Returns the empty string.
+     * @example
+     *
+     * _.times(2, _.stubString);
+     * // => ['', '']
+     */
+    function stubString() {
+      return '';
+    }
+
+    /**
+     * This method returns `true`.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.13.0
+     * @category Util
+     * @returns {boolean} Returns `true`.
+     * @example
+     *
+     * _.times(2, _.stubTrue);
+     * // => [true, true]
+     */
+    function stubTrue() {
+      return true;
+    }
+
+    /**
+     * Invokes the iteratee `n` times, returning an array of the results of
+     * each invocation. The iteratee is invoked with one argument; (index).
+     *
+     * @static
+     * @since 0.1.0
+     * @memberOf _
+     * @category Util
+     * @param {number} n The number of times to invoke `iteratee`.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @returns {Array} Returns the array of results.
+     * @example
+     *
+     * _.times(3, String);
+     * // => ['0', '1', '2']
+     *
+     *  _.times(4, _.constant(0));
+     * // => [0, 0, 0, 0]
+     */
+    function times(n, iteratee) {
+      n = toInteger(n);
+      if (n < 1 || n > MAX_SAFE_INTEGER) {
+        return [];
+      }
+      var index = MAX_ARRAY_LENGTH,
+          length = nativeMin(n, MAX_ARRAY_LENGTH);
+
+      iteratee = getIteratee(iteratee);
+      n -= MAX_ARRAY_LENGTH;
+
+      var result = baseTimes(length, iteratee);
       while (++index < n) {
-        result[index] = callback(index);
+        iteratee(index);
       }
       return result;
     }
 
     /**
-     * The inverse of `_.escape` this method converts the HTML entities
-     * `&amp;`, `&lt;`, `&gt;`, `&quot;`, and `&#39;` in `string` to their
-     * corresponding characters.
+     * Converts `value` to a property path array.
      *
      * @static
      * @memberOf _
-     * @category Utilities
-     * @param {string} string The string to unescape.
-     * @returns {string} Returns the unescaped string.
+     * @since 4.0.0
+     * @category Util
+     * @param {*} value The value to convert.
+     * @returns {Array} Returns the new property path array.
      * @example
      *
-     * _.unescape('Fred, Barney &amp; Pebbles');
-     * // => 'Fred, Barney & Pebbles'
+     * _.toPath('a.b.c');
+     * // => ['a', 'b', 'c']
+     *
+     * _.toPath('a[0].b.c');
+     * // => ['a', '0', 'b', 'c']
      */
-    function unescape(string) {
-      return string == null ? '' : String(string).replace(reEscapedHtml, unescapeHtmlChar);
+    function toPath(value) {
+      if (isArray(value)) {
+        return arrayMap(value, toKey);
+      }
+      return isSymbol(value) ? [value] : copyArray(stringToPath(toString(value)));
     }
 
     /**
-     * Generates a unique ID. If `prefix` is provided the ID will be appended to it.
+     * Generates a unique ID. If `prefix` is given, the ID is appended to it.
      *
      * @static
+     * @since 0.1.0
      * @memberOf _
-     * @category Utilities
-     * @param {string} [prefix] The value to prefix the ID with.
+     * @category Util
+     * @param {string} [prefix=''] The value to prefix the ID with.
      * @returns {string} Returns the unique ID.
      * @example
      *
@@ -6757,226 +16266,539 @@
      */
     function uniqueId(prefix) {
       var id = ++idCounter;
-      return String(prefix == null ? '' : prefix) + id;
+      return toString(prefix) + id;
     }
 
-    /*--------------------------------------------------------------------------*/
+    /*------------------------------------------------------------------------*/
 
     /**
-     * Creates a `lodash` object that wraps the given value with explicit
-     * method chaining enabled.
+     * Adds two numbers.
      *
      * @static
      * @memberOf _
-     * @category Chaining
-     * @param {*} value The value to wrap.
-     * @returns {Object} Returns the wrapper object.
+     * @since 3.4.0
+     * @category Math
+     * @param {number} augend The first number in an addition.
+     * @param {number} addend The second number in an addition.
+     * @returns {number} Returns the total.
      * @example
      *
-     * var characters = [
-     *   { 'name': 'barney',  'age': 36 },
-     *   { 'name': 'fred',    'age': 40 },
-     *   { 'name': 'pebbles', 'age': 1 }
-     * ];
+     * _.add(6, 4);
+     * // => 10
+     */
+    var add = createMathOperation(function(augend, addend) {
+      return augend + addend;
+    }, 0);
+
+    /**
+     * Computes `number` rounded up to `precision`.
      *
-     * var youngest = _.chain(characters)
-     *     .sortBy('age')
-     *     .map(function(chr) { return chr.name + ' is ' + chr.age; })
-     *     .first()
-     *     .value();
-     * // => 'pebbles is 1'
+     * @static
+     * @memberOf _
+     * @since 3.10.0
+     * @category Math
+     * @param {number} number The number to round up.
+     * @param {number} [precision=0] The precision to round up to.
+     * @returns {number} Returns the rounded up number.
+     * @example
+     *
+     * _.ceil(4.006);
+     * // => 5
+     *
+     * _.ceil(6.004, 2);
+     * // => 6.01
+     *
+     * _.ceil(6040, -2);
+     * // => 6100
      */
-    function chain(value) {
-      value = new lodashWrapper(value);
-      value.__chain__ = true;
-      return value;
+    var ceil = createRound('ceil');
+
+    /**
+     * Divide two numbers.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.7.0
+     * @category Math
+     * @param {number} dividend The first number in a division.
+     * @param {number} divisor The second number in a division.
+     * @returns {number} Returns the quotient.
+     * @example
+     *
+     * _.divide(6, 4);
+     * // => 1.5
+     */
+    var divide = createMathOperation(function(dividend, divisor) {
+      return dividend / divisor;
+    }, 1);
+
+    /**
+     * Computes `number` rounded down to `precision`.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.10.0
+     * @category Math
+     * @param {number} number The number to round down.
+     * @param {number} [precision=0] The precision to round down to.
+     * @returns {number} Returns the rounded down number.
+     * @example
+     *
+     * _.floor(4.006);
+     * // => 4
+     *
+     * _.floor(0.046, 2);
+     * // => 0.04
+     *
+     * _.floor(4060, -2);
+     * // => 4000
+     */
+    var floor = createRound('floor');
+
+    /**
+     * Computes the maximum value of `array`. If `array` is empty or falsey,
+     * `undefined` is returned.
+     *
+     * @static
+     * @since 0.1.0
+     * @memberOf _
+     * @category Math
+     * @param {Array} array The array to iterate over.
+     * @returns {*} Returns the maximum value.
+     * @example
+     *
+     * _.max([4, 2, 8, 6]);
+     * // => 8
+     *
+     * _.max([]);
+     * // => undefined
+     */
+    function max(array) {
+      return (array && array.length)
+        ? baseExtremum(array, identity, baseGt)
+        : undefined;
     }
 
     /**
-     * Invokes `interceptor` with the `value` as the first argument and then
-     * returns `value`. The purpose of this method is to "tap into" a method
-     * chain in order to perform operations on intermediate results within
-     * the chain.
+     * This method is like `_.max` except that it accepts `iteratee` which is
+     * invoked for each element in `array` to generate the criterion by which
+     * the value is ranked. The iteratee is invoked with one argument: (value).
      *
      * @static
      * @memberOf _
-     * @category Chaining
-     * @param {*} value The value to provide to `interceptor`.
-     * @param {Function} interceptor The function to invoke.
-     * @returns {*} Returns `value`.
+     * @since 4.0.0
+     * @category Math
+     * @param {Array} array The array to iterate over.
+     * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+     * @returns {*} Returns the maximum value.
      * @example
      *
-     * _([1, 2, 3, 4])
-     *  .tap(function(array) { array.pop(); })
-     *  .reverse()
-     *  .value();
-     * // => [3, 2, 1]
+     * var objects = [{ 'n': 1 }, { 'n': 2 }];
+     *
+     * _.maxBy(objects, function(o) { return o.n; });
+     * // => { 'n': 2 }
+     *
+     * // The `_.property` iteratee shorthand.
+     * _.maxBy(objects, 'n');
+     * // => { 'n': 2 }
      */
-    function tap(value, interceptor) {
-      interceptor(value);
-      return value;
+    function maxBy(array, iteratee) {
+      return (array && array.length)
+        ? baseExtremum(array, getIteratee(iteratee, 2), baseGt)
+        : undefined;
     }
 
     /**
-     * Enables explicit method chaining on the wrapper object.
+     * Computes the mean of the values in `array`.
      *
-     * @name chain
+     * @static
      * @memberOf _
-     * @category Chaining
-     * @returns {*} Returns the wrapper object.
+     * @since 4.0.0
+     * @category Math
+     * @param {Array} array The array to iterate over.
+     * @returns {number} Returns the mean.
      * @example
      *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
-     * ];
+     * _.mean([4, 2, 8, 6]);
+     * // => 5
+     */
+    function mean(array) {
+      return baseMean(array, identity);
+    }
+
+    /**
+     * This method is like `_.mean` except that it accepts `iteratee` which is
+     * invoked for each element in `array` to generate the value to be averaged.
+     * The iteratee is invoked with one argument: (value).
      *
-     * // without explicit chaining
-     * _(characters).first();
-     * // => { 'name': 'barney', 'age': 36 }
-     *
-     * // with explicit chaining
-     * _(characters).chain()
-     *   .first()
-     *   .pick('age')
-     *   .value();
-     * // => { 'age': 36 }
+     * @static
+     * @memberOf _
+     * @since 4.7.0
+     * @category Math
+     * @param {Array} array The array to iterate over.
+     * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+     * @returns {number} Returns the mean.
+     * @example
+     *
+     * var objects = [{ 'n': 4 }, { 'n': 2 }, { 'n': 8 }, { 'n': 6 }];
+     *
+     * _.meanBy(objects, function(o) { return o.n; });
+     * // => 5
+     *
+     * // The `_.property` iteratee shorthand.
+     * _.meanBy(objects, 'n');
+     * // => 5
      */
-    function wrapperChain() {
-      this.__chain__ = true;
-      return this;
+    function meanBy(array, iteratee) {
+      return baseMean(array, getIteratee(iteratee, 2));
     }
 
     /**
-     * Produces the `toString` result of the wrapped value.
+     * Computes the minimum value of `array`. If `array` is empty or falsey,
+     * `undefined` is returned.
      *
-     * @name toString
+     * @static
+     * @since 0.1.0
      * @memberOf _
-     * @category Chaining
-     * @returns {string} Returns the string result.
+     * @category Math
+     * @param {Array} array The array to iterate over.
+     * @returns {*} Returns the minimum value.
      * @example
      *
-     * _([1, 2, 3]).toString();
-     * // => '1,2,3'
+     * _.min([4, 2, 8, 6]);
+     * // => 2
+     *
+     * _.min([]);
+     * // => undefined
      */
-    function wrapperToString() {
-      return String(this.__wrapped__);
+    function min(array) {
+      return (array && array.length)
+        ? baseExtremum(array, identity, baseLt)
+        : undefined;
     }
 
     /**
-     * Extracts the wrapped value.
+     * This method is like `_.min` except that it accepts `iteratee` which is
+     * invoked for each element in `array` to generate the criterion by which
+     * the value is ranked. The iteratee is invoked with one argument: (value).
      *
-     * @name valueOf
+     * @static
      * @memberOf _
-     * @alias value
-     * @category Chaining
-     * @returns {*} Returns the wrapped value.
+     * @since 4.0.0
+     * @category Math
+     * @param {Array} array The array to iterate over.
+     * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+     * @returns {*} Returns the minimum value.
      * @example
      *
-     * _([1, 2, 3]).valueOf();
-     * // => [1, 2, 3]
+     * var objects = [{ 'n': 1 }, { 'n': 2 }];
+     *
+     * _.minBy(objects, function(o) { return o.n; });
+     * // => { 'n': 1 }
+     *
+     * // The `_.property` iteratee shorthand.
+     * _.minBy(objects, 'n');
+     * // => { 'n': 1 }
      */
-    function wrapperValueOf() {
-      return this.__wrapped__;
+    function minBy(array, iteratee) {
+      return (array && array.length)
+        ? baseExtremum(array, getIteratee(iteratee, 2), baseLt)
+        : undefined;
     }
 
-    /*--------------------------------------------------------------------------*/
+    /**
+     * Multiply two numbers.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.7.0
+     * @category Math
+     * @param {number} multiplier The first number in a multiplication.
+     * @param {number} multiplicand The second number in a multiplication.
+     * @returns {number} Returns the product.
+     * @example
+     *
+     * _.multiply(6, 4);
+     * // => 24
+     */
+    var multiply = createMathOperation(function(multiplier, multiplicand) {
+      return multiplier * multiplicand;
+    }, 1);
+
+    /**
+     * Computes `number` rounded to `precision`.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.10.0
+     * @category Math
+     * @param {number} number The number to round.
+     * @param {number} [precision=0] The precision to round to.
+     * @returns {number} Returns the rounded number.
+     * @example
+     *
+     * _.round(4.006);
+     * // => 4
+     *
+     * _.round(4.006, 2);
+     * // => 4.01
+     *
+     * _.round(4060, -2);
+     * // => 4100
+     */
+    var round = createRound('round');
+
+    /**
+     * Subtract two numbers.
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Math
+     * @param {number} minuend The first number in a subtraction.
+     * @param {number} subtrahend The second number in a subtraction.
+     * @returns {number} Returns the difference.
+     * @example
+     *
+     * _.subtract(6, 4);
+     * // => 2
+     */
+    var subtract = createMathOperation(function(minuend, subtrahend) {
+      return minuend - subtrahend;
+    }, 0);
+
+    /**
+     * Computes the sum of the values in `array`.
+     *
+     * @static
+     * @memberOf _
+     * @since 3.4.0
+     * @category Math
+     * @param {Array} array The array to iterate over.
+     * @returns {number} Returns the sum.
+     * @example
+     *
+     * _.sum([4, 2, 8, 6]);
+     * // => 20
+     */
+    function sum(array) {
+      return (array && array.length)
+        ? baseSum(array, identity)
+        : 0;
+    }
+
+    /**
+     * This method is like `_.sum` except that it accepts `iteratee` which is
+     * invoked for each element in `array` to generate the value to be summed.
+     * The iteratee is invoked with one argument: (value).
+     *
+     * @static
+     * @memberOf _
+     * @since 4.0.0
+     * @category Math
+     * @param {Array} array The array to iterate over.
+     * @param {Function} [iteratee=_.identity] The iteratee invoked per element.
+     * @returns {number} Returns the sum.
+     * @example
+     *
+     * var objects = [{ 'n': 4 }, { 'n': 2 }, { 'n': 8 }, { 'n': 6 }];
+     *
+     * _.sumBy(objects, function(o) { return o.n; });
+     * // => 20
+     *
+     * // The `_.property` iteratee shorthand.
+     * _.sumBy(objects, 'n');
+     * // => 20
+     */
+    function sumBy(array, iteratee) {
+      return (array && array.length)
+        ? baseSum(array, getIteratee(iteratee, 2))
+        : 0;
+    }
+
+    /*------------------------------------------------------------------------*/
 
-    // add functions that return wrapped values when chaining
+    // Add methods that return wrapped values in chain sequences.
     lodash.after = after;
+    lodash.ary = ary;
     lodash.assign = assign;
+    lodash.assignIn = assignIn;
+    lodash.assignInWith = assignInWith;
+    lodash.assignWith = assignWith;
     lodash.at = at;
+    lodash.before = before;
     lodash.bind = bind;
     lodash.bindAll = bindAll;
     lodash.bindKey = bindKey;
+    lodash.castArray = castArray;
     lodash.chain = chain;
+    lodash.chunk = chunk;
     lodash.compact = compact;
-    lodash.compose = compose;
+    lodash.concat = concat;
+    lodash.cond = cond;
+    lodash.conforms = conforms;
     lodash.constant = constant;
     lodash.countBy = countBy;
     lodash.create = create;
-    lodash.createCallback = createCallback;
     lodash.curry = curry;
+    lodash.curryRight = curryRight;
     lodash.debounce = debounce;
     lodash.defaults = defaults;
+    lodash.defaultsDeep = defaultsDeep;
     lodash.defer = defer;
     lodash.delay = delay;
     lodash.difference = difference;
+    lodash.differenceBy = differenceBy;
+    lodash.differenceWith = differenceWith;
+    lodash.drop = drop;
+    lodash.dropRight = dropRight;
+    lodash.dropRightWhile = dropRightWhile;
+    lodash.dropWhile = dropWhile;
+    lodash.fill = fill;
     lodash.filter = filter;
+    lodash.flatMap = flatMap;
+    lodash.flatMapDeep = flatMapDeep;
+    lodash.flatMapDepth = flatMapDepth;
     lodash.flatten = flatten;
-    lodash.forEach = forEach;
-    lodash.forEachRight = forEachRight;
-    lodash.forIn = forIn;
-    lodash.forInRight = forInRight;
-    lodash.forOwn = forOwn;
-    lodash.forOwnRight = forOwnRight;
+    lodash.flattenDeep = flattenDeep;
+    lodash.flattenDepth = flattenDepth;
+    lodash.flip = flip;
+    lodash.flow = flow;
+    lodash.flowRight = flowRight;
+    lodash.fromPairs = fromPairs;
     lodash.functions = functions;
+    lodash.functionsIn = functionsIn;
     lodash.groupBy = groupBy;
-    lodash.indexBy = indexBy;
     lodash.initial = initial;
     lodash.intersection = intersection;
+    lodash.intersectionBy = intersectionBy;
+    lodash.intersectionWith = intersectionWith;
     lodash.invert = invert;
-    lodash.invoke = invoke;
+    lodash.invertBy = invertBy;
+    lodash.invokeMap = invokeMap;
+    lodash.iteratee = iteratee;
+    lodash.keyBy = keyBy;
     lodash.keys = keys;
+    lodash.keysIn = keysIn;
     lodash.map = map;
+    lodash.mapKeys = mapKeys;
     lodash.mapValues = mapValues;
-    lodash.max = max;
+    lodash.matches = matches;
+    lodash.matchesProperty = matchesProperty;
     lodash.memoize = memoize;
     lodash.merge = merge;
-    lodash.min = min;
+    lodash.mergeWith = mergeWith;
+    lodash.method = method;
+    lodash.methodOf = methodOf;
+    lodash.mixin = mixin;
+    lodash.negate = negate;
+    lodash.nthArg = nthArg;
     lodash.omit = omit;
+    lodash.omitBy = omitBy;
     lodash.once = once;
-    lodash.pairs = pairs;
+    lodash.orderBy = orderBy;
+    lodash.over = over;
+    lodash.overArgs = overArgs;
+    lodash.overEvery = overEvery;
+    lodash.overSome = overSome;
     lodash.partial = partial;
     lodash.partialRight = partialRight;
+    lodash.partition = partition;
     lodash.pick = pick;
-    lodash.pluck = pluck;
+    lodash.pickBy = pickBy;
     lodash.property = property;
+    lodash.propertyOf = propertyOf;
     lodash.pull = pull;
+    lodash.pullAll = pullAll;
+    lodash.pullAllBy = pullAllBy;
+    lodash.pullAllWith = pullAllWith;
+    lodash.pullAt = pullAt;
     lodash.range = range;
+    lodash.rangeRight = rangeRight;
+    lodash.rearg = rearg;
     lodash.reject = reject;
     lodash.remove = remove;
     lodash.rest = rest;
+    lodash.reverse = reverse;
+    lodash.sampleSize = sampleSize;
+    lodash.set = set;
+    lodash.setWith = setWith;
     lodash.shuffle = shuffle;
+    lodash.slice = slice;
     lodash.sortBy = sortBy;
+    lodash.sortedUniq = sortedUniq;
+    lodash.sortedUniqBy = sortedUniqBy;
+    lodash.split = split;
+    lodash.spread = spread;
+    lodash.tail = tail;
+    lodash.take = take;
+    lodash.takeRight = takeRight;
+    lodash.takeRightWhile = takeRightWhile;
+    lodash.takeWhile = takeWhile;
     lodash.tap = tap;
     lodash.throttle = throttle;
-    lodash.times = times;
+    lodash.thru = thru;
     lodash.toArray = toArray;
+    lodash.toPairs = toPairs;
+    lodash.toPairsIn = toPairsIn;
+    lodash.toPath = toPath;
+    lodash.toPlainObject = toPlainObject;
     lodash.transform = transform;
+    lodash.unary = unary;
     lodash.union = union;
+    lodash.unionBy = unionBy;
+    lodash.unionWith = unionWith;
     lodash.uniq = uniq;
+    lodash.uniqBy = uniqBy;
+    lodash.uniqWith = uniqWith;
+    lodash.unset = unset;
+    lodash.unzip = unzip;
+    lodash.unzipWith = unzipWith;
+    lodash.update = update;
+    lodash.updateWith = updateWith;
     lodash.values = values;
-    lodash.where = where;
+    lodash.valuesIn = valuesIn;
     lodash.without = without;
+    lodash.words = words;
     lodash.wrap = wrap;
     lodash.xor = xor;
+    lodash.xorBy = xorBy;
+    lodash.xorWith = xorWith;
     lodash.zip = zip;
     lodash.zipObject = zipObject;
+    lodash.zipObjectDeep = zipObjectDeep;
+    lodash.zipWith = zipWith;
 
-    // add aliases
-    lodash.collect = map;
-    lodash.drop = rest;
-    lodash.each = forEach;
-    lodash.eachRight = forEachRight;
-    lodash.extend = assign;
-    lodash.methods = functions;
-    lodash.object = zipObject;
-    lodash.select = filter;
-    lodash.tail = rest;
-    lodash.unique = uniq;
-    lodash.unzip = zip;
-
-    // add functions to `lodash.prototype`
-    mixin(lodash);
-
-    /*--------------------------------------------------------------------------*/
-
-    // add functions that return unwrapped values when chaining
+    // Add aliases.
+    lodash.entries = toPairs;
+    lodash.entriesIn = toPairsIn;
+    lodash.extend = assignIn;
+    lodash.extendWith = assignInWith;
+
+    // Add methods to `lodash.prototype`.
+    mixin(lodash, lodash);
+
+    /*------------------------------------------------------------------------*/
+
+    // Add methods that return unwrapped values in chain sequences.
+    lodash.add = add;
+    lodash.attempt = attempt;
+    lodash.camelCase = camelCase;
+    lodash.capitalize = capitalize;
+    lodash.ceil = ceil;
+    lodash.clamp = clamp;
     lodash.clone = clone;
     lodash.cloneDeep = cloneDeep;
-    lodash.contains = contains;
+    lodash.cloneDeepWith = cloneDeepWith;
+    lodash.cloneWith = cloneWith;
+    lodash.conformsTo = conformsTo;
+    lodash.deburr = deburr;
+    lodash.defaultTo = defaultTo;
+    lodash.divide = divide;
+    lodash.endsWith = endsWith;
+    lodash.eq = eq;
     lodash.escape = escape;
+    lodash.escapeRegExp = escapeRegExp;
     lodash.every = every;
     lodash.find = find;
     lodash.findIndex = findIndex;
@@ -6984,197 +16806,404 @@
     lodash.findLast = findLast;
     lodash.findLastIndex = findLastIndex;
     lodash.findLastKey = findLastKey;
+    lodash.floor = floor;
+    lodash.forEach = forEach;
+    lodash.forEachRight = forEachRight;
+    lodash.forIn = forIn;
+    lodash.forInRight = forInRight;
+    lodash.forOwn = forOwn;
+    lodash.forOwnRight = forOwnRight;
+    lodash.get = get;
+    lodash.gt = gt;
+    lodash.gte = gte;
     lodash.has = has;
+    lodash.hasIn = hasIn;
+    lodash.head = head;
     lodash.identity = identity;
+    lodash.includes = includes;
     lodash.indexOf = indexOf;
+    lodash.inRange = inRange;
+    lodash.invoke = invoke;
     lodash.isArguments = isArguments;
     lodash.isArray = isArray;
+    lodash.isArrayBuffer = isArrayBuffer;
+    lodash.isArrayLike = isArrayLike;
+    lodash.isArrayLikeObject = isArrayLikeObject;
     lodash.isBoolean = isBoolean;
+    lodash.isBuffer = isBuffer;
     lodash.isDate = isDate;
     lodash.isElement = isElement;
     lodash.isEmpty = isEmpty;
     lodash.isEqual = isEqual;
+    lodash.isEqualWith = isEqualWith;
+    lodash.isError = isError;
     lodash.isFinite = isFinite;
     lodash.isFunction = isFunction;
+    lodash.isInteger = isInteger;
+    lodash.isLength = isLength;
+    lodash.isMap = isMap;
+    lodash.isMatch = isMatch;
+    lodash.isMatchWith = isMatchWith;
     lodash.isNaN = isNaN;
+    lodash.isNative = isNative;
+    lodash.isNil = isNil;
     lodash.isNull = isNull;
     lodash.isNumber = isNumber;
     lodash.isObject = isObject;
+    lodash.isObjectLike = isObjectLike;
     lodash.isPlainObject = isPlainObject;
     lodash.isRegExp = isRegExp;
+    lodash.isSafeInteger = isSafeInteger;
+    lodash.isSet = isSet;
     lodash.isString = isString;
+    lodash.isSymbol = isSymbol;
+    lodash.isTypedArray = isTypedArray;
     lodash.isUndefined = isUndefined;
+    lodash.isWeakMap = isWeakMap;
+    lodash.isWeakSet = isWeakSet;
+    lodash.join = join;
+    lodash.kebabCase = kebabCase;
+    lodash.last = last;
     lodash.lastIndexOf = lastIndexOf;
-    lodash.mixin = mixin;
+    lodash.lowerCase = lowerCase;
+    lodash.lowerFirst = lowerFirst;
+    lodash.lt = lt;
+    lodash.lte = lte;
+    lodash.max = max;
+    lodash.maxBy = maxBy;
+    lodash.mean = mean;
+    lodash.meanBy = meanBy;
+    lodash.min = min;
+    lodash.minBy = minBy;
+    lodash.stubArray = stubArray;
+    lodash.stubFalse = stubFalse;
+    lodash.stubObject = stubObject;
+    lodash.stubString = stubString;
+    lodash.stubTrue = stubTrue;
+    lodash.multiply = multiply;
+    lodash.nth = nth;
     lodash.noConflict = noConflict;
     lodash.noop = noop;
     lodash.now = now;
+    lodash.pad = pad;
+    lodash.padEnd = padEnd;
+    lodash.padStart = padStart;
     lodash.parseInt = parseInt;
     lodash.random = random;
     lodash.reduce = reduce;
     lodash.reduceRight = reduceRight;
+    lodash.repeat = repeat;
+    lodash.replace = replace;
     lodash.result = result;
+    lodash.round = round;
     lodash.runInContext = runInContext;
+    lodash.sample = sample;
     lodash.size = size;
+    lodash.snakeCase = snakeCase;
     lodash.some = some;
     lodash.sortedIndex = sortedIndex;
+    lodash.sortedIndexBy = sortedIndexBy;
+    lodash.sortedIndexOf = sortedIndexOf;
+    lodash.sortedLastIndex = sortedLastIndex;
+    lodash.sortedLastIndexBy = sortedLastIndexBy;
+    lodash.sortedLastIndexOf = sortedLastIndexOf;
+    lodash.startCase = startCase;
+    lodash.startsWith = startsWith;
+    lodash.subtract = subtract;
+    lodash.sum = sum;
+    lodash.sumBy = sumBy;
     lodash.template = template;
+    lodash.times = times;
+    lodash.toFinite = toFinite;
+    lodash.toInteger = toInteger;
+    lodash.toLength = toLength;
+    lodash.toLower = toLower;
+    lodash.toNumber = toNumber;
+    lodash.toSafeInteger = toSafeInteger;
+    lodash.toString = toString;
+    lodash.toUpper = toUpper;
+    lodash.trim = trim;
+    lodash.trimEnd = trimEnd;
+    lodash.trimStart = trimStart;
+    lodash.truncate = truncate;
     lodash.unescape = unescape;
     lodash.uniqueId = uniqueId;
+    lodash.upperCase = upperCase;
+    lodash.upperFirst = upperFirst;
+
+    // Add aliases.
+    lodash.each = forEach;
+    lodash.eachRight = forEachRight;
+    lodash.first = head;
 
-    // add aliases
-    lodash.all = every;
-    lodash.any = some;
-    lodash.detect = find;
-    lodash.findWhere = find;
-    lodash.foldl = reduce;
-    lodash.foldr = reduceRight;
-    lodash.include = contains;
-    lodash.inject = reduce;
-
-    mixin(function() {
-      var source = {}
-      forOwn(lodash, function(func, methodName) {
-        if (!lodash.prototype[methodName]) {
+    mixin(lodash, (function() {
+      var source = {};
+      baseForOwn(lodash, function(func, methodName) {
+        if (!hasOwnProperty.call(lodash.prototype, methodName)) {
           source[methodName] = func;
         }
       });
       return source;
-    }(), false);
+    }()), { 'chain': false });
 
-    /*--------------------------------------------------------------------------*/
-
-    // add functions capable of returning wrapped and unwrapped values when chaining
-    lodash.first = first;
-    lodash.last = last;
-    lodash.sample = sample;
-
-    // add aliases
-    lodash.take = first;
-    lodash.head = first;
-
-    forOwn(lodash, function(func, methodName) {
-      var callbackable = methodName !== 'sample';
-      if (!lodash.prototype[methodName]) {
-        lodash.prototype[methodName]= function(n, guard) {
-          var chainAll = this.__chain__,
-              result = func(this.__wrapped__, n, guard);
-
-          return !chainAll && (n == null || (guard && !(callbackable && typeof n == 'function')))
-            ? result
-            : new lodashWrapper(result, chainAll);
-        };
-      }
-    });
-
-    /*--------------------------------------------------------------------------*/
+    /*------------------------------------------------------------------------*/
 
     /**
      * The semantic version number.
      *
      * @static
      * @memberOf _
-     * @type string
+     * @type {string}
      */
-    lodash.VERSION = '2.4.2';
+    lodash.VERSION = VERSION;
 
-    // add "Chaining" functions to the wrapper
-    lodash.prototype.chain = wrapperChain;
-    lodash.prototype.toString = wrapperToString;
-    lodash.prototype.value = wrapperValueOf;
-    lodash.prototype.valueOf = wrapperValueOf;
-
-    // add `Array` functions that return unwrapped values
-    baseEach(['join', 'pop', 'shift'], function(methodName) {
-      var func = arrayRef[methodName];
-      lodash.prototype[methodName] = function() {
-        var chainAll = this.__chain__,
-            result = func.apply(this.__wrapped__, arguments);
+    // Assign default placeholders.
+    arrayEach(['bind', 'bindKey', 'curry', 'curryRight', 'partial', 'partialRight'], function(methodName) {
+      lodash[methodName].placeholder = lodash;
+    });
+
+    // Add `LazyWrapper` methods for `_.drop` and `_.take` variants.
+    arrayEach(['drop', 'take'], function(methodName, index) {
+      LazyWrapper.prototype[methodName] = function(n) {
+        n = n === undefined ? 1 : nativeMax(toInteger(n), 0);
+
+        var result = (this.__filtered__ && !index)
+          ? new LazyWrapper(this)
+          : this.clone();
+
+        if (result.__filtered__) {
+          result.__takeCount__ = nativeMin(n, result.__takeCount__);
+        } else {
+          result.__views__.push({
+            'size': nativeMin(n, MAX_ARRAY_LENGTH),
+            'type': methodName + (result.__dir__ < 0 ? 'Right' : '')
+          });
+        }
+        return result;
+      };
+
+      LazyWrapper.prototype[methodName + 'Right'] = function(n) {
+        return this.reverse()[methodName](n).reverse();
+      };
+    });
+
+    // Add `LazyWrapper` methods that accept an `iteratee` value.
+    arrayEach(['filter', 'map', 'takeWhile'], function(methodName, index) {
+      var type = index + 1,
+          isFilter = type == LAZY_FILTER_FLAG || type == LAZY_WHILE_FLAG;
+
+      LazyWrapper.prototype[methodName] = function(iteratee) {
+        var result = this.clone();
+        result.__iteratees__.push({
+          'iteratee': getIteratee(iteratee, 3),
+          'type': type
+        });
+        result.__filtered__ = result.__filtered__ || isFilter;
+        return result;
+      };
+    });
+
+    // Add `LazyWrapper` methods for `_.head` and `_.last`.
+    arrayEach(['head', 'last'], function(methodName, index) {
+      var takeName = 'take' + (index ? 'Right' : '');
 
-        return chainAll
-          ? new lodashWrapper(result, chainAll)
-          : result;
+      LazyWrapper.prototype[methodName] = function() {
+        return this[takeName](1).value()[0];
       };
     });
 
-    // add `Array` functions that return the existing wrapped value
-    baseEach(['push', 'reverse', 'sort', 'unshift'], function(methodName) {
-      var func = arrayRef[methodName];
+    // Add `LazyWrapper` methods for `_.initial` and `_.tail`.
+    arrayEach(['initial', 'tail'], function(methodName, index) {
+      var dropName = 'drop' + (index ? '' : 'Right');
+
+      LazyWrapper.prototype[methodName] = function() {
+        return this.__filtered__ ? new LazyWrapper(this) : this[dropName](1);
+      };
+    });
+
+    LazyWrapper.prototype.compact = function() {
+      return this.filter(identity);
+    };
+
+    LazyWrapper.prototype.find = function(predicate) {
+      return this.filter(predicate).head();
+    };
+
+    LazyWrapper.prototype.findLast = function(predicate) {
+      return this.reverse().find(predicate);
+    };
+
+    LazyWrapper.prototype.invokeMap = baseRest(function(path, args) {
+      if (typeof path == 'function') {
+        return new LazyWrapper(this);
+      }
+      return this.map(function(value) {
+        return baseInvoke(value, path, args);
+      });
+    });
+
+    LazyWrapper.prototype.reject = function(predicate) {
+      return this.filter(negate(getIteratee(predicate)));
+    };
+
+    LazyWrapper.prototype.slice = function(start, end) {
+      start = toInteger(start);
+
+      var result = this;
+      if (result.__filtered__ && (start > 0 || end < 0)) {
+        return new LazyWrapper(result);
+      }
+      if (start < 0) {
+        result = result.takeRight(-start);
+      } else if (start) {
+        result = result.drop(start);
+      }
+      if (end !== undefined) {
+        end = toInteger(end);
+        result = end < 0 ? result.dropRight(-end) : result.take(end - start);
+      }
+      return result;
+    };
+
+    LazyWrapper.prototype.takeRightWhile = function(predicate) {
+      return this.reverse().takeWhile(predicate).reverse();
+    };
+
+    LazyWrapper.prototype.toArray = function() {
+      return this.take(MAX_ARRAY_LENGTH);
+    };
+
+    // Add `LazyWrapper` methods to `lodash.prototype`.
+    baseForOwn(LazyWrapper.prototype, function(func, methodName) {
+      var checkIteratee = /^(?:filter|find|map|reject)|While$/.test(methodName),
+          isTaker = /^(?:head|last)$/.test(methodName),
+          lodashFunc = lodash[isTaker ? ('take' + (methodName == 'last' ? 'Right' : '')) : methodName],
+          retUnwrapped = isTaker || /^find/.test(methodName);
+
+      if (!lodashFunc) {
+        return;
+      }
       lodash.prototype[methodName] = function() {
-        func.apply(this.__wrapped__, arguments);
-        return this;
+        var value = this.__wrapped__,
+            args = isTaker ? [1] : arguments,
+            isLazy = value instanceof LazyWrapper,
+            iteratee = args[0],
+            useLazy = isLazy || isArray(value);
+
+        var interceptor = function(value) {
+          var result = lodashFunc.apply(lodash, arrayPush([value], args));
+          return (isTaker && chainAll) ? result[0] : result;
+        };
+
+        if (useLazy && checkIteratee && typeof iteratee == 'function' && iteratee.length != 1) {
+          // Avoid lazy use if the iteratee has a "length" value other than `1`.
+          isLazy = useLazy = false;
+        }
+        var chainAll = this.__chain__,
+            isHybrid = !!this.__actions__.length,
+            isUnwrapped = retUnwrapped && !chainAll,
+            onlyLazy = isLazy && !isHybrid;
+
+        if (!retUnwrapped && useLazy) {
+          value = onlyLazy ? value : new LazyWrapper(this);
+          var result = func.apply(value, args);
+          result.__actions__.push({ 'func': thru, 'args': [interceptor], 'thisArg': undefined });
+          return new LodashWrapper(result, chainAll);
+        }
+        if (isUnwrapped && onlyLazy) {
+          return func.apply(this, args);
+        }
+        result = this.thru(interceptor);
+        return isUnwrapped ? (isTaker ? result.value()[0] : result.value()) : result;
       };
     });
 
-    // add `Array` functions that return new wrapped values
-    baseEach(['concat', 'slice', 'splice'], function(methodName) {
-      var func = arrayRef[methodName];
+    // Add `Array` methods to `lodash.prototype`.
+    arrayEach(['pop', 'push', 'shift', 'sort', 'splice', 'unshift'], function(methodName) {
+      var func = arrayProto[methodName],
+          chainName = /^(?:push|sort|unshift)$/.test(methodName) ? 'tap' : 'thru',
+          retUnwrapped = /^(?:pop|shift)$/.test(methodName);
+
       lodash.prototype[methodName] = function() {
-        return new lodashWrapper(func.apply(this.__wrapped__, arguments), this.__chain__);
+        var args = arguments;
+        if (retUnwrapped && !this.__chain__) {
+          var value = this.value();
+          return func.apply(isArray(value) ? value : [], args);
+        }
+        return this[chainName](function(value) {
+          return func.apply(isArray(value) ? value : [], args);
+        });
       };
     });
 
-    // avoid array-like object bugs with `Array#shift` and `Array#splice`
-    // in IE < 9, Firefox < 10, Narwhal, and RingoJS
-    if (!support.spliceObjects) {
-      baseEach(['pop', 'shift', 'splice'], function(methodName) {
-        var func = arrayRef[methodName],
-            isSplice = methodName == 'splice';
-
-        lodash.prototype[methodName] = function() {
-          var chainAll = this.__chain__,
-              value = this.__wrapped__,
-              result = func.apply(value, arguments);
-
-          if (value.length === 0) {
-            delete value[0];
-          }
-          return (chainAll || isSplice)
-            ? new lodashWrapper(result, chainAll)
-            : result;
-        };
-      });
-    }
+    // Map minified method names to their real names.
+    baseForOwn(LazyWrapper.prototype, function(func, methodName) {
+      var lodashFunc = lodash[methodName];
+      if (lodashFunc) {
+        var key = lodashFunc.name + '';
+        if (!hasOwnProperty.call(realNames, key)) {
+          realNames[key] = [];
+        }
+        realNames[key].push({ 'name': methodName, 'func': lodashFunc });
+      }
+    });
 
-    // add pseudo private property to be used and removed during the build process
-    lodash._baseEach = baseEach;
-    lodash._iteratorTemplate = iteratorTemplate;
-    lodash._shimKeys = shimKeys;
+    realNames[createHybrid(undefined, WRAP_BIND_KEY_FLAG).name] = [{
+      'name': 'wrapper',
+      'func': undefined
+    }];
+
+    // Add methods to `LazyWrapper`.
+    LazyWrapper.prototype.clone = lazyClone;
+    LazyWrapper.prototype.reverse = lazyReverse;
+    LazyWrapper.prototype.value = lazyValue;
 
+    // Add chain sequence methods to the `lodash` wrapper.
+    lodash.prototype.at = wrapperAt;
+    lodash.prototype.chain = wrapperChain;
+    lodash.prototype.commit = wrapperCommit;
+    lodash.prototype.next = wrapperNext;
+    lodash.prototype.plant = wrapperPlant;
+    lodash.prototype.reverse = wrapperReverse;
+    lodash.prototype.toJSON = lodash.prototype.valueOf = lodash.prototype.value = wrapperValue;
+
+    // Add lazy aliases.
+    lodash.prototype.first = lodash.prototype.head;
+
+    if (symIterator) {
+      lodash.prototype[symIterator] = wrapperToIterator;
+    }
     return lodash;
-  }
+  });
 
   /*--------------------------------------------------------------------------*/
 
-  // expose Lo-Dash
+  // Export lodash.
   var _ = runInContext();
 
-  // some AMD build optimizers like r.js check for condition patterns like the following:
+  // Some AMD build optimizers, like r.js, check for condition patterns like:
   if (typeof define == 'function' && typeof define.amd == 'object' && define.amd) {
-    // Expose Lo-Dash to the global object even when an AMD loader is present in
-    // case Lo-Dash is loaded with a RequireJS shim config.
-    // See http://requirejs.org/docs/api.html#config-shim
+    // Expose Lodash on the global object to prevent errors when Lodash is
+    // loaded by a script tag in the presence of an AMD loader.
+    // See http://requirejs.org/docs/errors.html#mismatch for more details.
+    // Use `_.noConflict` to remove Lodash from the global object.
     root._ = _;
 
-    // define as an anonymous module so, through path mapping, it can be
-    // referenced as the "underscore" module
+    // Define as an anonymous module so, through path mapping, it can be
+    // referenced as the "underscore" module.
     define(function() {
       return _;
     });
   }
-  // check for `exports` after `define` in case a build optimizer adds an `exports` object
-  else if (freeExports && freeModule) {
-    // in Node.js or RingoJS
-    if (moduleExports) {
-      (freeModule.exports = _)._ = _;
-    }
-    // in Narwhal or Rhino -require
-    else {
-      freeExports._ = _;
-    }
+  // Check for `exports` after `define` in case a build optimizer adds it.
+  else if (freeModule) {
+    // Export for Node.js.
+    (freeModule.exports = _)._ = _;
+    // Export for CommonJS support.
+    freeExports._ = _;
   }
   else {
-    // in a browser or Rhino
+    // Export to the global object.
     root._ = _;
   }
 }.call(this));
Index: /branches/rel_ag_9_4_0_493_SBOM/restfulapi/proxy/media/node_modules/grunt/node_modules/grunt-legacy-log/node_modules/lodash/package.json
===================================================================
--- /branches/rel_ag_9_4_0_493_SBOM/restfulapi/proxy/media/node_modules/grunt/node_modules/grunt-legacy-log/node_modules/lodash/package.json	(revision 20239)
+++ /branches/rel_ag_9_4_0_493_SBOM/restfulapi/proxy/media/node_modules/grunt/node_modules/grunt-legacy-log/node_modules/lodash/package.json	(working copy)
@@ -1,106 +1,17 @@
 {
   "name": "lodash",
-  "version": "2.4.2",
-  "description": "A utility library delivering consistency, customization, performance, & extras.",
-  "homepage": "http://lodash.com/",
+  "version": "4.17.21",
+  "description": "Lodash modular utilities.",
+  "keywords": "modules, stdlib, util",
+  "homepage": "https://lodash.com/",
+  "repository": "lodash/lodash",
+  "icon": "https://lodash.com/icon.svg",
   "license": "MIT",
-  "main": "dist/lodash.js",
-  "keywords": [
-    "amd",
-    "browser",
-    "client",
-    "customize",
-    "functional",
-    "server",
-    "util"
-  ],
-  "author": {
-    "name": "John-David Dalton",
-    "email": "john.david.dalton@gmail.com",
-    "url": "http://allyoucanleet.com/"
-  },
+  "main": "lodash.js",
+  "author": "John-David Dalton <john.david.dalton@gmail.com>",
   "contributors": [
-    {
-      "name": "John-David Dalton",
-      "email": "john.david.dalton@gmail.com",
-      "url": "http://allyoucanleet.com/"
-    },
-    {
-      "name": "Blaine Bublitz",
-      "email": "blaine@iceddev.com",
-      "url": "http://www.iceddev.com/"
-    },
-    {
-      "name": "Kit Cambridge",
-      "email": "github@kitcambridge.be",
-      "url": "http://kitcambridge.be/"
-    },
-    {
-      "name": "Mathias Bynens",
-      "email": "mathias@qiwi.be",
-      "url": "http://mathiasbynens.be/"
-    }
-  ],
-  "bugs": {
-    "url": "https://github.com/lodash/lodash/issues"
-  },
-  "repository": {
-    "type": "git",
-    "url": "https://github.com/lodash/lodash.git"
-  },
-  "engines": [
-    "node",
-    "rhino"
-  ],
-  "files": [
-    "LICENSE.txt",
-    "lodash.js",
-    "dist/lodash.js",
-    "dist/lodash.min.js",
-    "dist/lodash.compat.js",
-    "dist/lodash.compat.min.js",
-    "dist/lodash.underscore.js",
-    "dist/lodash.underscore.min.js"
+    "John-David Dalton <john.david.dalton@gmail.com>",
+    "Mathias Bynens <mathias@qiwi.be>"
   ],
-  "jam": {
-    "main": "dist/lodash.compat.js",
-    "include": [
-      "LICENSE.txt",
-      "dist/lodash.js",
-      "dist/lodash.min.js",
-      "dist/lodash.compat.js",
-      "dist/lodash.compat.min.js",
-      "dist/lodash.underscore.js",
-      "dist/lodash.underscore.min.js"
-    ]
-  },
-  "volo": {
-    "type": "directory",
-    "ignore": [
-      ".*",
-      "*.custom.*",
-      "*.min.*",
-      "*.template.*",
-      "*.map",
-      "*.md",
-      "lodash.js",
-      "index.js",
-      "bower.json",
-      "component.json",
-      "doc",
-      "modularize",
-      "node_modules",
-      "perf",
-      "test",
-      "vendor"
-    ]
-  },
-  "readme": "# Lo-Dash v2.4.2\nA utility library delivering consistency, [customization](https://lodash.com/custom-builds), [performance](https://lodash.com/benchmarks), & [extras](https://lodash.com/#features).\n\n## Download\n\nCheck out our [wiki]([https://github.com/lodash/lodash/wiki/build-differences]) for details over the differences between builds.\n\n* Modern builds perfect for newer browsers/environments:<br>\n[Development](https://raw.github.com/lodash/lodash/2.4.2/dist/lodash.js) &\n[Production](https://raw.github.com/lodash/lodash/2.4.2/dist/lodash.min.js)\n\n* Compatibility builds for older environment support too:<br>\n[Development](https://raw.github.com/lodash/lodash/2.4.2/dist/lodash.compat.js) &\n[Production](https://raw.github.com/lodash/lodash/2.4.2/dist/lodash.compat.min.js)\n\n* Underscore builds to use as a drop-in replacement:<br>\n[Development](https://raw.github.com/lodash/lodash/2.4.2/dist/lodash.underscore.js) &\n[Production](https://raw.github.com/lodash/lodash/2.4.2/dist/lodash.underscore.min.js)\n\nCDN copies are available on [cdnjs](http://cdnjs.com/libraries/lodash.js/) & [jsDelivr](http://www.jsdelivr.com/#!lodash). For smaller file sizes, create [custom builds](https://lodash.com/custom-builds) with only the features needed.\n\nLove modules? We’ve got you covered with [lodash-amd](https://npmjs.org/package/lodash-amd), [lodash-es6](https://github.com/lodash/lodash-es6), [lodash-node](https://npmjs.org/package/lodash-node), & [npm packages](https://npmjs.org/browse/keyword/lodash-modularized) per method.\n\n## Dive in\n\nThere’s plenty of **[documentation](https://lodash.com/docs)**, [unit tests](https://lodash.com/tests), & [benchmarks](https://lodash.com/benchmarks).<br>\nCheck out <a href=\"http://devdocs.io/lodash/\">DevDocs</a> as a fast, organized, & searchable interface for our documentation.\n\nThe full changelog for this release is available on our [wiki](https://github.com/lodash/lodash/wiki/Changelog).<br>\nA list of upcoming features is available on our [roadmap](https://github.com/lodash/lodash/wiki/Roadmap).\n\n## Installation & usage\n\nIn browsers:\n\n```html\n<script src=\"lodash.js\"></script>\n```\n\nUsing [`npm`](http://npmjs.org/):\n\n```bash\nnpm i --save lodash\n\n{sudo} npm i -g lodash\nnpm ln lodash\n```\n\nIn [Node.js](http://nodejs.org/) & [Ringo](http://ringojs.org/):\n\n```js\nvar _ = require('lodash');\n// or as Underscore\nvar _ = require('lodash/dist/lodash.underscore');\n```\n\n**Notes:**\n * Don’t assign values to [special variable](http://nodejs.org/api/repl.html#repl_repl_features) `_` when in the REPL\n * If Lo-Dash is installed globally, run [`npm ln lodash`](http://blog.nodejs.org/2011/03/23/npm-1-0-global-vs-local-installation/) in your project’s root directory *before* requiring it\n\nIn [Rhino](http://www.mozilla.org/rhino/):\n\n```js\nload('lodash.js');\n```\n\nIn an AMD loader:\n\n```js\nrequire({\n  'packages': [\n    { 'name': 'lodash', 'location': 'path/to/lodash', 'main': 'lodash' }\n  ]\n},\n['lodash'], function(_) {\n  console.log(_.VERSION);\n});\n```\n\n## Resources\n\n * Podcasts\n  - [JavaScript Jabber](http://javascriptjabber.com/079-jsj-lo-dash-with-john-david-dalton/)\n\n * Posts\n  - [Say “Hello” to Lo-Dash](http://kitcambridge.be/blog/say-hello-to-lo-dash/)\n  - [Custom builds in Lo-Dash 2.0](http://kitcambridge.be/blog/custom-builds-in-lo-dash-2-dot-0/)\n\n * Videos\n  - [Introduction](https://vimeo.com/44154599)\n  - [Origins](https://vimeo.com/44154600)\n  - [Optimizations & builds](https://vimeo.com/44154601)\n  - [Native method use](https://vimeo.com/48576012)\n  - [Testing](https://vimeo.com/45865290)\n  - [CascadiaJS ’12](http://www.youtube.com/watch?v=dpPy4f_SeEk)\n\n A list of other community created podcasts, posts, & videos is available on our [wiki](https://github.com/lodash/lodash/wiki/Resources).\n\n## Features\n\n * AMD loader support ([curl](https://github.com/cujojs/curl), [dojo](http://dojotoolkit.org/), [requirejs](http://requirejs.org/), etc.)\n * [_(…)](https://lodash.com/docs#_) supports intuitive chaining\n * [_.at](https://lodash.com/docs#at) for cherry-picking collection values\n * [_.bindKey](https://lodash.com/docs#bindKey) for binding [*“lazy”*](http://michaux.ca/articles/lazy-function-definition-pattern) defined methods\n * [_.clone](https://lodash.com/docs#clone) supports shallow cloning of `Date` & `RegExp` objects\n * [_.cloneDeep](https://lodash.com/docs#cloneDeep) for deep cloning arrays & objects\n * [_.constant](https://lodash.com/docs#constant) & [_.property](https://lodash.com/docs#property) function generators for composing functions\n * [_.contains](https://lodash.com/docs#contains) accepts a `fromIndex`\n * [_.create](https://lodash.com/docs#create) for easier object inheritance\n * [_.createCallback](https://lodash.com/docs#createCallback) for extending callbacks in methods & mixins\n * [_.curry](https://lodash.com/docs#curry) for creating [curried](http://hughfdjackson.com/javascript/2013/07/06/why-curry-helps/) functions\n * [_.debounce](https://lodash.com/docs#debounce) & [_.throttle](https://lodash.com/docs#throttle) accept additional `options` for more control\n * [_.findIndex](https://lodash.com/docs#findIndex) & [_.findKey](https://lodash.com/docs#findKey) for finding indexes & keys\n * [_.forEach](https://lodash.com/docs#forEach) is chainable & supports exiting early\n * [_.forIn](https://lodash.com/docs#forIn) for iterating own & inherited properties\n * [_.forOwn](https://lodash.com/docs#forOwn) for iterating own properties\n * [_.isPlainObject](https://lodash.com/docs#isPlainObject) for checking if values are created by `Object`\n * [_.mapValues](https://lodash.com/docs#mapValues) for [mapping](https://lodash.com/docs#map) values to an object\n * [_.memoize](https://lodash.com/docs#memoize) exposes the `cache` of memoized functions\n * [_.merge](https://lodash.com/docs#merge) for a deep [_.extend](https://lodash.com/docs#extend)\n * [_.noop](https://lodash.com/docs#noop) for function placeholders\n * [_.now](https://lodash.com/docs#now) as a cross-browser `Date.now` alternative\n * [_.parseInt](https://lodash.com/docs#parseInt) for consistent behavior\n * [_.pull](https://lodash.com/docs#pull) & [_.remove](https://lodash.com/docs#remove) for mutating arrays\n * [_.random](https://lodash.com/docs#random) supports returning floating-point numbers\n * [_.runInContext](https://lodash.com/docs#runInContext) for easier mocking\n * [_.sortBy](https://lodash.com/docs#sortBy) supports sorting by multiple properties\n * [_.support](https://lodash.com/docs#support) for flagging environment features\n * [_.template](https://lodash.com/docs#template) supports [*“imports”*](https://lodash.com/docs#templateSettings_imports) options & [ES6 template delimiters](http://people.mozilla.org/~jorendorff/es6-draft.html#sec-literals-string-literals)\n * [_.transform](https://lodash.com/docs#transform) as a powerful alternative to [_.reduce](https://lodash.com/docs#reduce) for transforming objects\n * [_.where](https://lodash.com/docs#where) supports deep object comparisons\n * [_.xor](https://lodash.com/docs#xor) as a companion to [_.difference](https://lodash.com/docs#difference), [_.intersection](https://lodash.com/docs#intersection), & [_.union](https://lodash.com/docs#union)\n * [_.zip](https://lodash.com/docs#zip) is capable of unzipping values\n * [_.omit](https://lodash.com/docs#omit), [_.pick](https://lodash.com/docs#pick), &\n   [more](https://lodash.com/docs \"_.assign, _.clone, _.cloneDeep, _.first, _.initial, _.isEqual, _.last, _.merge, _.rest\") accept callbacks\n * [_.contains](https://lodash.com/docs#contains), [_.toArray](https://lodash.com/docs#toArray), &\n   [more](https://lodash.com/docs \"_.at, _.countBy, _.every, _.filter, _.find, _.forEach, _.forEachRight, _.groupBy, _.invoke, _.map, _.max, _.min, _.pluck, _.reduce, _.reduceRight, _.reject, _.shuffle, _.size, _.some, _.sortBy, _.where\") accept strings\n * [_.filter](https://lodash.com/docs#filter), [_.map](https://lodash.com/docs#map), &\n   [more](https://lodash.com/docs \"_.countBy, _.every, _.find, _.findKey, _.findLast, _.findLastIndex, _.findLastKey, _.first, _.groupBy, _.initial, _.last, _.max, _.min, _.reject, _.rest, _.some, _.sortBy, _.sortedIndex, _.uniq\") support *“_.pluck”* & *“_.where”* shorthands\n * [_.findLast](https://lodash.com/docs#findLast), [_.findLastIndex](https://lodash.com/docs#findLastIndex), &\n   [more](https://lodash.com/docs \"_.findLastKey, _.forEachRight, _.forInRight, _.forOwnRight, _.partialRight\") right-associative methods\n\n## Support\n\nTested in Chrome 5~31, Firefox 2~25, IE 6-11, Opera 9.25-17, Safari 3-7, Node.js 0.6.21-0.10.22, Narwhal 0.3.2, PhantomJS 1.9.2, RingoJS 0.9, & Rhino 1.7RC5.\n",
-  "readmeFilename": "README.md",
-  "_id": "lodash@2.4.2",
-  "dist": {
-    "shasum": "9f50ad85be9bff0d601fc48d1f428c05507ddcff"
-  },
-  "_from": "lodash@~2.4.1",
-  "_resolved": "https://registry.npmjs.org/lodash/-/lodash-2.4.2.tgz"
+  "scripts": { "test": "echo \"See https://travis-ci.org/lodash-archive/lodash-cli for testing details.\"" }
 }
