lodash/dist/lodash.js

A utility library delivering consistency, customization, performance, & extras.

/**
 * @license
 * Lo-Dash 2.4.0 (Custom Build) <http://lodash.com/>
 * Build: `lodash modern -o ./dist/lodash.js`
 * 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 <http://lodash.com/license>
 */
;(function() {

  /** 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 to generate unique IDs */
  var idCounter = 0;

  /** Used to prefix keys to avoid issues with `__proto__` and properties on `Object.prototype` */
  var keyPrefix = +new Date + '';

  /** Used as the size when optimizations are enabled for large arrays */
  var largeArraySize = 75;

  /** Used as the max size of the `arrayPool` and `objectPool` */
  var maxPoolSize = 40;

  /** Used to detect and test whitespace */
  var whitespace = (
    // whitespace
    ' \t\x0B\f\xA0\ufeff' +

    // line terminators
    '\n\r\u2028\u2029' +

    // unicode category "Zs" space separators
    '\u1680\u180e\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u202f\u205f\u3000'
  );

  /** 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 ES6 template delimiters
   * http://people.mozilla.org/~jorendorff/es6-draft.html#sec-literals-string-literals
   */
  var reEsTemplate = /\$\{([^\\}]*(?:\\.[^\\}]*)*)\}/g;

  /** 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 match "interpolate" template delimiters */
  var reInterpolate = /<%=([\s\S]+?)%>/g;

  /** Used to match leading whitespace and zeros to be removed */
  var reLeadingSpacesAndZeros = RegExp('^[' + whitespace + ']*0+(?=.$)');

  /** 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\t\u2028\u2029\\]/g;

  /** Used to assign default `context` object properties */
  var contextProps = [
    'Array', 'Boolean', 'Date', 'Function', 'Math', 'Number', 'Object',
    'RegExp', 'String', '_', 'attachEvent', 'clearTimeout', 'isFinite', 'isNaN',
    'parseInt', 'setTimeout'
  ];

  /** Used to make template sourceURLs easier to identify */
  var templateCounter = 0;

  /** `Object#toString` result shortcuts */
  var argsClass = '[object Arguments]',
      arrayClass = '[object Array]',
      boolClass = '[object Boolean]',
      dateClass = '[object Date]',
      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 as the property descriptor for `__bindData__` */
  var descriptor = {
    'configurable': false,
    'enumerable': false,
    'value': null,
    'writable': false
  };

  /** 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 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;

  /** Detect free variable `exports` */
  var freeExports = objectTypes[typeof exports] && exports && !exports.nodeType && exports;

  /** Detect free variable `module` */
  var freeModule = objectTypes[typeof module] && module && !module.nodeType && module;

  /** 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;
  }

  /*--------------------------------------------------------------------------*/

  /**
   * The base implementation of `_.indexOf` without support for binary searches
   * or `fromIndex` constraints.
   *
   * @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`.
   */
  function baseIndexOf(array, value, fromIndex) {
    var index = (fromIndex || 0) - 1,
        length = array ? array.length : 0;

    while (++index < length) {
      if (array[index] === value) {
        return index;
      }
    }
    return -1;
  }

  /**
   * An implementation of `_.contains` for cache objects that mimics the return
   * signature of `_.indexOf` by returning `0` if the value is found, else `-1`.
   *
   * @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`.
   */
  function cacheIndexOf(cache, value) {
    var type = typeof value;
    cache = cache.cache;

    if (type == 'boolean' || value == null) {
      return cache[value] ? 0 : -1;
    }
    if (type != 'number' && type != 'string') {
      type = 'object';
    }
    var key = type == 'number' ? value : keyPrefix + value;
    cache = (cache = cache[type]) && cache[key];

    return type == 'object'
      ? (cache && baseIndexOf(cache, value) > -1 ? 0 : -1)
      : (cache ? 0 : -1);
  }

  /**
   * Adds a given value to the corresponding cache object.
   *
   * @private
   * @param {*} value The value to add to the cache.
   */
  function cachePush(value) {
    var cache = this.cache,
        type = typeof value;

    if (type == 'boolean' || value == null) {
      cache[value] = true;
    } else {
      if (type != 'number' && type != 'string') {
        type = 'object';
      }
      var key = type == 'number' ? value : keyPrefix + value,
          typeCache = cache[type] || (cache[type] = {});

      if (type == 'object') {
        (typeCache[key] || (typeCache[key] = [])).push(value);
      } else {
        typeCache[key] = true;
      }
    }
  }

  /**
   * Used by `_.max` and `_.min` as the default callback when a given
   * collection is a string value.
   *
   * @private
   * @param {string} value The character to inspect.
   * @returns {number} Returns the code unit of given character.
   */
  function charAtCallback(value) {
    return value.charCodeAt(0);
  }

  /**
   * Used by `sortBy` to compare transformed `collection` elements, stable sorting
   * them in ascending order.
   *
   * @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`.
   */
  function compareAscending(a, b) {
    var ac = a.criteria,
        bc = b.criteria,
        index = -1,
        length = ac.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;
        }
      }
    }
    // 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;
  }

  /**
   * Creates a cache object to optimize linear searches of large arrays.
   *
   * @private
   * @param {Array} [array=[]] The array to search.
   * @returns {null|Object} Returns the cache object or `null` if caching should not be used.
   */
  function createCache(array) {
    var index = -1,
        length = array.length,
        first = array[0],
        mid = array[(length / 2) | 0],
        last = array[length - 1];

    if (first && typeof first == 'object' &&
        mid && typeof mid == 'object' && last && typeof last == 'object') {
      return false;
    }
    var cache = getObject();
    cache['false'] = cache['null'] = cache['true'] = cache['undefined'] = false;

    var result = getObject();
    result.array = array;
    result.cache = cache;
    result.push = cachePush;

    while (++index < length) {
      result.push(array[index]);
    }
    return result;
  }

  /**
   * Used by `template` to escape characters for inclusion in compiled
   * string literals.
   *
   * @private
   * @param {string} match The matched character to escape.
   * @returns {string} Returns the escaped character.
   */
  function escapeStringChar(match) {
    return '\\' + stringEscapes[match];
  }

  /**
   * Gets an array from the array pool or creates a new one if the pool is empty.
   *
   * @private
   * @returns {Array} The array from the pool.
   */
  function getArray() {
    return arrayPool.pop() || [];
  }

  /**
   * Gets an object from the object pool or creates a new one if the pool is empty.
   *
   * @private
   * @returns {Object} The object from the pool.
   */
  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
    };
  }

  /**
   * Releases the given array back to the array pool.
   *
   * @private
   * @param {Array} [array] The array to release.
   */
  function releaseArray(array) {
    array.length = 0;
    if (arrayPool.length < maxPoolSize) {
      arrayPool.push(array);
    }
  }

  /**
   * Releases the given object back to the object pool.
   *
   * @private
   * @param {Object} [object] The object to release.
   */
  function releaseObject(object) {
    var cache = object.cache;
    if (cache) {
      releaseObject(cache);
    }
    object.array = object.cache = object.criteria = object.object = object.number = object.string = object.value = null;
    if (objectPool.length < maxPoolSize) {
      objectPool.push(object);
    }
  }

  /**
   * Slices the `collection` from the `start` index up to, but not including,
   * the `end` index.
   *
   * 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 {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.
   */
  function slice(array, start, end) {
    start || (start = 0);
    if (typeof end == 'undefined') {
      end = array ? array.length : 0;
    }
    var index = -1,
        length = end - start || 0,
        result = Array(length < 0 ? 0 : length);

    while (++index < length) {
      result[index] = array[start + index];
    }
    return result;
  }

  /*--------------------------------------------------------------------------*/

  /**
   * Create a new `lodash` function using the given context object.
   *
   * @static
   * @memberOf _
   * @category Utilities
   * @param {Object} [context=root] The context object.
   * @returns {Function} Returns the `lodash` function.
   */
  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;

    /** Native constructor references */
    var Array = context.Array,
        Boolean = context.Boolean,
        Date = context.Date,
        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 objectProto = Object.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 to detect if a method is native */
    var reNative = RegExp('^' +
      String(toString)
        .replace(/[.*+?^${}()|[\]\\]/g, '\\$&')
        .replace(/toString| for [^\]]+/g, '.*?') + '$'
    );

    /** Native method shortcuts */
    var ceil = Math.ceil,
        clearTimeout = context.clearTimeout,
        floor = Math.floor,
        fnToString = Function.prototype.toString,
        getPrototypeOf = reNative.test(getPrototypeOf = Object.getPrototypeOf) && getPrototypeOf,
        hasOwnProperty = objectProto.hasOwnProperty,
        push = arrayRef.push,
        setTimeout = context.setTimeout,
        splice = arrayRef.splice;

    /** Used to set meta data on functions */
    var defineProperty = (function() {
      // IE 8 only accepts DOM elements
      try {
        var o = {},
            func = reNative.test(func = Object.defineProperty) && func,
            result = func(o, o, o) && func;
      } catch(e) { }
      return result;
    }());

    /* Native method shortcuts for methods with the same name as other `lodash` methods */
    var nativeCreate = reNative.test(nativeCreate = Object.create) && nativeCreate,
        nativeIsArray = reNative.test(nativeIsArray = Array.isArray) && nativeIsArray,
        nativeIsFinite = context.isFinite,
        nativeIsNaN = context.isNaN,
        nativeKeys = reNative.test(nativeKeys = Object.keys) && nativeKeys,
        nativeMax = Math.max,
        nativeMin = Math.min,
        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;

    /*--------------------------------------------------------------------------*/

    /**
     * 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.
     *
     * @name _
     * @constructor
     * @category Chaining
     * @param {*} value The value to wrap in a `lodash` instance.
     * @returns {Object} Returns a `lodash` instance.
     * @example
     *
     * var wrapped = _([1, 2, 3]);
     *
     * // returns an unwrapped value
     * wrapped.reduce(function(sum, num) {
     *   return sum + num;
     * });
     * // => 6
     *
     * // returns a wrapped value
     * var squares = wrapped.map(function(num) {
     *   return num * num;
     * });
     *
     * _.isArray(squares);
     * // => false
     *
     * _.isArray(squares.value());
     * // => 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);
    }

    /**
     * A fast path for creating `lodash` wrapper objects.
     *
     * @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.
     */
    function lodashWrapper(value, chainAll) {
      this.__chain__ = !!chainAll;
      this.__wrapped__ = value;
    }
    // ensure `new lodashWrapper` is an instance of `lodash`
    lodashWrapper.prototype = lodash.prototype;

    /**
     * An object used to flag environments features.
     *
     * @static
     * @memberOf _
     * @type Object
     */
    var support = lodash.support = {};

    /**
     * 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 = !reNative.test(context.WinRTError) && reThis.test(runInContext);

    /**
     * Detect if `Function#name` is supported (all but IE).
     *
     * @memberOf _.support
     * @type boolean
     */
    support.funcNames = typeof Function.name == 'string';

    /**
     * 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.
     *
     * @static
     * @memberOf _
     * @type Object
     */
    lodash.templateSettings = {

      /**
       * Used to detect `data` property values to be HTML-escaped.
       *
       * @memberOf _.templateSettings
       * @type RegExp
       */
      'escape': /<%-([\s\S]+?)%>/g,

      /**
       * Used to detect code to be evaluated.
       *
       * @memberOf _.templateSettings
       * @type RegExp
       */
      'evaluate': /<%([\s\S]+?)%>/g,

      /**
       * Used to detect `data` property values to inject.
       *
       * @memberOf _.templateSettings
       * @type RegExp
       */
      'interpolate': reInterpolate,

      /**
       * Used to reference the data object in the template text.
       *
       * @memberOf _.templateSettings
       * @type string
       */
      'variable': '',

      /**
       * Used to import variables into the compiled template.
       *
       * @memberOf _.templateSettings
       * @type Object
       */
      'imports': {

        /**
         * A reference to the `lodash` function.
         *
         * @memberOf _.templateSettings.imports
         * @type Function
         */
        '_': lodash
      }
    };

    /*--------------------------------------------------------------------------*/

    /**
     * The base implementation of `_.bind` that creates the bound function and
     * sets its meta data.
     *
     * @private
     * @param {Array} bindData The bind data array.
     * @returns {Function} Returns the new bound function.
     */
    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) {
          var args = partialArgs.slice();
          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);
      }
      setBindData(bound, bindData);
      return bound;
    }

    /**
     * The base implementation of `_.clone` without argument juggling or support
     * for `thisArg` binding.
     *
     * @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.
     */
    function baseClone(value, isDeep, callback, stackA, stackB) {
      if (callback) {
        var result = callback(value);
        if (typeof result != 'undefined') {
          return result;
        }
      }
      // inspect [[Class]]
      var isObj = isObject(value);
      if (isObj) {
        var className = toString.call(value);
        if (!cloneableClasses[className]) {
          return value;
        }
        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;
        }
      } else {
        return 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];
          }
        }
        result = isArr ? ctor(value.length) : {};
      }
      else {
        result = isArr ? slice(value) : assign({}, value);
      }
      // add array properties assigned by `RegExp#exec`
      if (isArr) {
        if (hasOwnProperty.call(value, 'index')) {
          result.index = value.index;
        }
        if (hasOwnProperty.call(value, 'input')) {
          result.input = value.input;
        }
      }
      // exit for shallow clone
      if (!isDeep) {
        return result;
      }
      // 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 ? forEach : forOwn)(value, function(objValue, key) {
        result[key] = baseClone(objValue, isDeep, callback, stackA, stackB);
      });

      if (initedStack) {
        releaseArray(stackA);
        releaseArray(stackB);
      }
      return result;
    }

    /**
     * The base implementation of `_.create` without support for assigning
     * properties to the created object.
     *
     * @private
     * @param {Object} prototype The object to inherit from.
     * @returns {Object} Returns the new object.
     */
    function baseCreate(prototype, properties) {
      return isObject(prototype) ? nativeCreate(prototype) : {};
    }
    // 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 `_.createCallback` without support for creating
     * "_.pluck" or "_.where" style callbacks.
     *
     * @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.
     */
    function baseCreateCallback(func, thisArg, argCount) {
      if (typeof func != 'function') {
        return identity;
      }
      // exit early for no `thisArg` or already bound by `Function#bind`
      if (typeof thisArg == 'undefined' || !('prototype' in func)) {
        return func;
      }
      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);
          }
        }
      }
      // exit early if there are no `this` references or `func` is bound
      if (bindData === false || (bindData !== true && bindData[1] & 1)) {
        return func;
      }
      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);
        };
      }
      return bind(func, thisArg);
    }

    /**
     * The base implementation of `createWrapper` that creates the wrapper and
     * sets its meta data.
     *
     * @private
     * @param {Array} bindData The bind data array.
     * @returns {Function} Returns the new function.
     */
    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 = partialArgs.slice();
          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;
    }

    /**
     * The base implementation of `_.difference` that accepts a single array
     * of values to exclude.
     *
     * @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.
     */
    function baseDifference(array, values) {
      var index = -1,
          indexOf = getIndexOf(),
          length = array ? array.length : 0,
          isLarge = length >= largeArraySize && indexOf === baseIndexOf,
          result = [];

      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);
        }
      }
      if (isLarge) {
        releaseObject(values);
      }
      return result;
    }

    /**
     * The base implementation of `_.flatten` without support for callback
     * shorthands or `thisArg` binding.
     *
     * @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 = [];

      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];
          }
        } else if (!isStrict) {
          result.push(value);
        }
      }
      return result;
    }

    /**
     * The base implementation of `_.isEqual`, without support for `thisArg` binding,
     * that allows partial "_.where" style comparisons.
     *
     * @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.
     * @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;
      }
      // 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);

      if (className == argsClass) {
        className = objectClass;
      }
      if (otherClass == argsClass) {
        otherClass = objectClass;
      }
      if (className != otherClass) {
        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__');

        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) {
          return false;
        }
        // in older versions of Opera, `arguments` objects have `Array` constructors
        var ctorA = a.constructor,
            ctorB = 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)
            ) {
          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());

      var length = stackA.length;
      while (length--) {
        if (stackA[length] == a) {
          return stackB[length] == b;
        }
      }
      var size = 0;
      result = true;

      // add `a` and `b` to the stack of traversed objects
      stackA.push(a);
      stackB.push(b);

      // recursively compare objects and arrays (susceptible to call stack limits)
      if (isArr) {
        length = a.length;
        size = b.length;

        // compare lengths to determine if a deep comparison is necessary
        result = size == a.length;
        if (!result && !isWhere) {
          return result;
        }
        // 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;
          }
        }
        return result;
      }
      // 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 (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);
          }
        });
      }
      if (initedStack) {
        releaseArray(stackA);
        releaseArray(stackB);
      }
      return result;
    }

    /**
     * The base implementation of `_.merge` without argument juggling or support
     * for `thisArg` binding.
     *
     * @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];

        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 (!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);
            }
          }
        }
        else {
          if (callback) {
            result = callback(value, source);
            if (typeof result == 'undefined') {
              result = source;
            }
          }
          if (typeof result != 'undefined') {
            value = result;
          }
        }
        object[key] = value;
      });
    }

    /**
     * The base implementation of `_.random` without argument juggling or support
     * for returning floating-point numbers.
     *
     * @private
     * @param {number} min The minimum possible value.
     * @param {number} max The maximum possible value.
     * @returns {number} Returns a random number.
     */
    function baseRandom(min, max) {
      return min + floor(nativeRandom() * (max - min + 1));
    }

    /**
     * The base implementation of `_.uniq` without support for callback shorthands
     * or `thisArg` binding.
     *
     * @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.
     */
    function baseUniq(array, isSorted, callback) {
      var index = -1,
          indexOf = getIndexOf(),
          length = array ? array.length : 0,
          result = [];

      var isLarge = !isSorted && length >= largeArraySize && indexOf === baseIndexOf,
          seen = (callback || isLarge) ? getArray() : result;

      if (isLarge) {
        var cache = createCache(seen);
        if (cache) {
          indexOf = cacheIndexOf;
          seen = cache;
        } else {
          isLarge = false;
          seen = callback ? seen : (releaseArray(seen), result);
        }
      }
      while (++index < length) {
        var value = array[index],
            computed = callback ? callback(value, index, array) : value;

        if (isSorted
              ? !index || seen[seen.length - 1] !== computed
              : indexOf(seen, computed) < 0
            ) {
          if (callback || isLarge) {
            seen.push(computed);
          }
          result.push(value);
        }
      }
      if (isLarge) {
        releaseArray(seen.array);
        releaseObject(seen);
      } else if (callback) {
        releaseArray(seen);
      }
      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.
     *
     * @private
     * @param {Function} setter The setter function.
     * @returns {Function} Returns the new aggregator function.
     */
    function createAggregator(setter) {
      return function(collection, callback, thisArg) {
        var result = {};
        callback = lodash.createCallback(callback, thisArg, 3);

        var index = -1,
            length = collection ? collection.length : 0;

        if (typeof length == 'number') {
          while (++index < length) {
            var value = collection[index];
            setter(result, value, callback(value, index, collection), collection);
          }
        } else {
          forOwn(collection, function(value, key, collection) {
            setter(result, value, callback(value, key, collection), collection);
          });
        }
        return result;
      };
    }

    /**
     * Creates a function that, when called, either curries or invokes `func`
     * with an optional `this` binding and partially applied arguments.
     *
     * @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 {*} [thisArg] The `this` binding of `func`.
     * @param {number} [arity] The arity of `func`.
     * @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) {
        bindData = bindData.slice();

        // 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) {
          push.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]);
    }

    /**
     * Used by `escape` to convert characters to HTML entities.
     *
     * @private
     * @param {string} match The matched character to escape.
     * @returns {string} Returns the escaped character.
     */
    function escapeHtmlChar(match) {
      return htmlEscapes[match];
    }

    /**
     * Gets the appropriate "indexOf" function. If the `_.indexOf` method is
     * customized, this method returns the custom method, otherwise it returns
     * the `baseIndexOf` function.
     *
     * @private
     * @returns {Function} Returns the "indexOf" function.
     */
    function getIndexOf() {
      var result = (result = lodash.indexOf) === indexOf ? baseIndexOf : result;
      return result;
    }

    /**
     * Sets `this` binding data on a given function.
     *
     * @private
     * @param {Function} func The function to set data on.
     * @param {Array} value The data array to set.
     */
    var setBindData = !defineProperty ? noop : function(func, value) {
      descriptor.value = value;
      defineProperty(func, '__bindData__', descriptor);
    };

    /**
     * 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.
     *
     * @private
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is a plain object, 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))) {
        return false;
      }
      // 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);
    }

    /**
     * Used by `unescape` to convert HTML entities to characters.
     *
     * @private
     * @param {string} match The matched character to unescape.
     * @returns {string} Returns the unescaped character.
     */
    function unescapeHtmlChar(match) {
      return htmlUnescapes[match];
    }

    /*--------------------------------------------------------------------------*/

    /**
     * Checks if `value` is an `arguments` object.
     *
     * @static
     * @memberOf _
     * @category Objects
     * @param {*} value The value to che