/files/lodash/2.2.1/lodash.underscore.js

/**
 * @license
 * Lo-Dash 2.2.1 (Custom Build) <http://lodash.com/>
 * Build: `lodash underscore exports="amd,commonjs,global,node" -o ./dist/lodash.underscore.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 generate unique IDs */
  var idCounter = 0;

  /** Used internally to indicate various things */
  var indicatorObject = {};

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

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

  /** Used to ensure capturing order of template delimiters */
  var reNoMatch = /($^)/;

  /** Used to match unescaped characters in compiled string literals */
  var reUnescapedString = /['\n\r\t\u2028\u2029\\]/g;

  /** `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 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;
  }

  /**
   * 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;

    // ensure a stable sort in V8 and other engines
    // http://code.google.com/p/v8/issues/detail?id=90
    if (ac !== bc) {
      if (ac > bc || typeof ac == 'undefined') {
        return 1;
      }
      if (ac < bc || typeof bc == 'undefined') {
        return -1;
      }
    }
    // The JS engine embedded in Adobe applications like InDesign has a buggy
    // `Array#sort` implementation that causes it, under certain circumstances,
    // to return the same value for `a` and `b`.
    // See https://github.com/jashkenas/underscore/pull/1247
    return a.index - b.index;
  }

  /**
   * 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];
  }

  /**
   * A no-operation function.
   *
   * @private
   */
  function noop() {
    // no operation performed
  }

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

  /**
   * 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 = root._;

  /** Used to detect if a method is native */
  var reNative = RegExp('^' +
    String(objectProto.valueOf)
      .replace(/[.*+?^${}()|[\]\\]/g, '\\$&')
      .replace(/valueOf|for [^\]]+/g, '.+?') + '$'
  );

  /** Native method shortcuts */
  var ceil = Math.ceil,
      floor = Math.floor,
      hasOwnProperty = objectProto.hasOwnProperty,
      now = reNative.test(now = Date.now) && now || function() { return +new Date; },
      push = arrayRef.push,
      toString = objectProto.toString,
      unshift = arrayRef.unshift;

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

  /** Detect various environments */
  var isIeOpera = reNative.test(root.attachEvent),
      isV8 = nativeBind && !/\n|true/.test(nativeBind + isIeOpera);

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

  /**
   * 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`, `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) {
    return (value instanceof lodash)
      ? 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 = {};

  (function() {
    var object = { '0': 1, 'length': 1 };

    /**
     * Detect if `Function#bind` exists and is inferred to be fast (all but V8).
     *
     * @memberOf _.support
     * @type boolean
     */
    support.fastBind = nativeBind && !isV8;

    /**
     * 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]);
  }(1));

  /**
   * 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': ''
  };

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

  /**
   * 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 if there is no `thisArg`
    if (typeof thisArg == 'undefined') {
      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 `_.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} [isArgArrays=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, isArgArrays, 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, isArgArrays);
        }
        var valIndex = -1,
            valLength = value.length,
            resIndex = result.length;

        result.length += valLength;
        while (++valIndex < valLength) {
          result[resIndex++] = value[valIndex];
        }
      } else if (!isArgArrays) {
        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, stackA, stackB) {
    if (a === b) {
      return a !== 0 || (1 / a == 1 / b);
    }
    var type = typeof a,
        otherType = typeof b;

    if (a === a &&
        !(a && objectTypes[type]) &&
        !(b && objectTypes[otherType])) {
      return false;
    }
    if (a == null || b == null) {
      return a === b;
    }
    var className = toString.call(a),
        otherClass = toString.call(b);

    if (className != otherClass) {
      return false;
    }
    switch (className) {
      case boolClass:
      case dateClass:
        return +a == +b;

      case numberClass:
        return a != +a
          ? b != +b
          : (a == 0 ? (1 / a == 1 / b) : a == +b);

      case regexpClass:
      case stringClass:
        return a == String(b);
    }
    var isArr = className == arrayClass;
    if (!isArr) {
      if (hasOwnProperty.call(a, '__wrapped__ ') || b instanceof lodash) {
        return baseIsEqual(a.__wrapped__ || a, b.__wrapped__ || b, stackA, stackB);
      }
      if (className != objectClass) {
        return false;
      }
      var ctorA = a.constructor,
          ctorB = b.constructor;

      if (ctorA != ctorB && !(
            isFunction(ctorA) && ctorA instanceof ctorA &&
            isFunction(ctorB) && ctorB instanceof ctorB
          )) {
        return false;
      }
    }
    stackA || (stackA = []);
    stackB || (stackB = []);

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

    stackA.push(a);
    stackB.push(b);

    if (isArr) {
      size = b.length;
      result = size == a.length;

      if (result) {
        while (size--) {
          if (!(result = baseIsEqual(a[size], b[size], stackA, stackB))) {
            break;
          }
        }
      }
      return result;
    }
    forIn(b, function(value, key, b) {
      if (hasOwnProperty.call(b, key)) {
        size++;
        return !(result = hasOwnProperty.call(a, key) && baseIsEqual(a[key], value, stackA, stackB)) && indicatorObject;
      }
    });

    if (result) {
      forIn(a, function(value, key, a) {
        if (hasOwnProperty.call(a, key)) {
          return !(result = --size > -1) && indicatorObject;
        }
      });
    }
    return result;
  }

  /**
   * 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 = [],
        seen = callback ? [] : 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) {
          seen.push(computed);
        }
        result.push(value);
      }
    }
    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 = 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 bound function.
   */
  function createBound(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,
        key = func;

    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;
    }
    // use `Function#bind` if it exists and is fast
    // (in V8 `Function#bind` is slower except when partially applied)
    if (isBind && !(isBindKey || isCurry || isPartialRight) &&
        (support.fastBind || (nativeBind && isPartial))) {
      if (isPartial) {
        var args = [thisArg];
        push.apply(args, partialArgs);
      }
      var bound = isPartial
        ? nativeBind.apply(func, args)
        : nativeBind.call(func, thisArg);
    }
    else {
      bound = function() {
        // `Function#bind` spec
        // http://es5.github.io/#x15.3.4.5
        var args = arguments,
            thisBinding = isBind ? thisArg : this;

        if (isCurry || isPartial || isPartialRight) {
          args = nativeSlice.call(args);
          if (isPartial) {
            unshift.apply(args, partialArgs);
          }
          if (isPartialRight) {
            push.apply(args, partialRightArgs);
          }
          if (isCurry && args.length < arity) {
            bitmask |= 16 & ~32;
            return createBound(func, (isCurryBound ? bitmask : bitmask & ~3), args, null, thisArg, arity);
          }
        }
        if (isBindKey) {
          func = thisBinding[key];
        }
        if (this instanceof bound) {
          // ensure `new bound` is an instance of `func`
          thisBinding = createObject(func.prototype);

          // mimic the constructor's `return` behavior
          // http://es5.github.io/#x13.2.2
          var result = func.apply(thisBinding, args);
          return isObject(result) ? result : thisBinding;
        }
        return func.apply(thisBinding, args);
      };
    }
    return bound;
  }

  /**
   * Creates a new object with the specified `prototype`.
   *
   * @private
   * @param {Object} prototype The prototype object.
   * @returns {Object} Returns the new object.
   */
  function createObject(prototype) {
    return isObject(prototype) ? nativeCreate(prototype) : {};
  }
  // fallback for browsers without `Object.create`
  if (!nativeCreate) {
    createObject = function(prototype) {
      if (isObject(prototype)) {
        noop.prototype = prototype;
        var result = new noop;
        noop.prototype = null;
      }
      return result || {};
    };
  }

  /**
   * 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;
  }

  /**
   * 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 check.
   * @returns {boolean} Returns `true` if the `value` is an `arguments` object, else `false`.
   * @example
   *
   * (function() { return _.isArguments(arguments); })(1, 2, 3);
   * // => true
   *
   * _.isArguments([1, 2, 3]);
   * // => 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 (!isArguments(arguments)) {
    isArguments = function(value) {
      return value && typeof value == 'object' && typeof value.length == 'number' &&
        hasOwnProperty.call(value, 'callee') || false;
    };
  }

  /**
   * Checks if `value` is an array.
   *
   * @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
   *
   * (function() { return _.isArray(arguments); })();
   * // => false
   *
   * _.isArray([1, 2, 3]);
   * // => true
   */
  var isArray = nativeIsArray || function(value) {
    return value && typeof value == 'object' && typeof value.length == 'number' &&
      toString.call(value) == arrayClass || false;
  };

  /**
   * A fallback implementation of `Object.keys` which produces an array of the
   * given object's own enumerable property names.
   *
   * @private
   * @type Function
   * @param {Object} object The object to inspect.
   * @returns {Array} Returns an array of property names.
   */
  var shimKeys = function(object) {
    var index, iterable = object, result = [];
    if (!iterable) return result;
    if (!(objectTypes[typeof object])) return result;
      for (index in iterable) {
        if (hasOwnProperty.call(iterable, index)) {
          result.push(index);
        }
      }
    return result
  };

  /**
   * Creates an array composed of the own enumerable property names of an object.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Object} object The object to inspect.
   * @returns {Array} Returns an array of property names.
   * @example
   *
   * _.keys({ 'one': 1, 'two': 2, 'three': 3 });
   * // => ['one', 'two', 'three'] (property order is not guaranteed across environments)
   */
  var keys = !nativeKeys ? shimKeys : function(object) {
    if (!isObject(object)) {
      return [];
    }
    return nativeKeys(object);
  };

  /**
   * Used to convert characters to HTML entities:
   *
   * 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;',
    "'": '&#x27;'
  };

  /** Used to convert HTML entities to characters */
  var htmlUnescapes = invert(htmlEscapes);

  /** Used to match HTML entities and HTML characters */
  var reEscapedHtml = RegExp('(' + keys(htmlUnescapes).join('|') + ')', 'g'),
      reUnescapedHtml = RegExp('[' + keys(htmlEscapes).join('') + ']', 'g');

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

  /**
   * 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).
   *
   * @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.
   * @example
   *
   * _.assign({ 'name': 'moe' }, { 'age': 40 });
   * // => { 'name': 'moe', 'age': 40 }
   *
   * var defaults = _.partialRight(_.assign, function(a, b) {
   *   return typeof a == 'undefined' ? b : a;
   * });
   *
   * var food = { 'name': 'apple' };
   * defaults(food, { 'name': 'banana', 'type': 'fruit' });
   * // => { 'name': 'apple', 'type': 'fruit' }
   */
  function assign(object) {
    if (!object) {
      return object;
    }
    for (var argsIndex = 1, argsLength = arguments.length; argsIndex < argsLength; argsIndex++) {
      var iterable = arguments[argsIndex];
      if (iterable) {
        for (var key in iterable) {
          object[key] = iterable[key];
        }
      }
    }
    return object;
  }

  /**
   * Creates a clone of `value`. If `deep` 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).
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {*} value The value to clone.
   * @param {boolean} [deep=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.
   * @example
   *
   * var stooges = [
   *   { 'name': 'moe', 'age': 40 },
   *   { 'name': 'larry', 'age': 50 }
   * ];
   *
   * var shallow = _.clone(stooges);
   * shallow[0] === stooges[0];
   * // => true
   *
   * var deep = _.clone(stooges, true);
   * deep[0] === stooges[0];
   * // => false
   *
   * _.mixin({
   *   'clone': _.partialRight(_.clone, function(value) {
   *     return _.isElement(value) ? value.cloneNode(false) : undefined;
   *   })
   * });
   *
   * var clone = _.clone(document.body);
   * clone.childNodes.length;
   * // => 0
   */
  function clone(value) {
    return isObject(value)
      ? (isArray(value) ? nativeSlice.call(value) : assign({}, value))
      : value;
  }

  /**
   * 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.
   *
   * @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.
   * @example
   *
   * var food = { 'name': 'apple' };
   * _.defaults(food, { 'name': 'banana', 'type': 'fruit' });
   * // => { 'name': 'apple', 'type': 'fruit' }
   */
  function defaults(object) {
    if (!object) {
      return object;
    }
    for (var argsIndex = 1, argsLength = arguments.length; argsIndex < argsLength; argsIndex++) {
      var iterable = arguments[argsIndex];
      if (iterable) {
        for (var key in iterable) {
          if (typeof object[key] == 'undefined') {
            object[key] = iterable[key];
          }
        }
      }
    }
    return object;
  }

  /**
   * 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`.
   *
   * @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`.
   * @example
   *
   * function Dog(name) {
   *   this.name = name;
   * }
   *
   * Dog.prototype.bark = function() {
   *   console.log('Woof, woof!');
   * };
   *
   * _.forIn(new Dog('Dagny'), function(value, key) {
   *   console.log(key);
   * });
   * // => logs 'bark' and 'name' (property order is not guaranteed across environments)
   */
  var forIn = function(collection, callback) {
    var index, iterable = collection, result = iterable;
    if (!iterable) return result;
    if (!objectTypes[typeof iterable]) return result;
      for (index in iterable) {
        if (callback(iterable[index], index, collection) === indicatorObject) return result;
      }
    return result
  };

  /**
   * 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`.
   *
   * @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`.
   * @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 forOwn = function(collection, callback) {
    var index, iterable = collection, result = iterable;
    if (!iterable) return result;
    if (!objectTypes[typeof iterable]) return result;
      for (index in iterable) {
        if (hasOwnProperty.call(iterable, index)) {
          if (callback(iterable[index], index, collection) === indicatorObject) return result;
        }
      }
    return result
  };

  /**
   * Creates a sorted array of property names of all enumerable properties,
   * own and inherited, of `object` that have function values.
   *
   * @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.
   * @example
   *
   * _.functions(_);
   * // => ['all', 'any', 'bind', 'bindAll', 'clone', 'compact', 'compose', ...]
   */
  function functions(object) {
    var result = [];
    forIn(object, function(value, key) {
      if (isFunction(value)) {
        result.push(key);
      }
    });
    return result.sort();
  }

  /**
   * Checks if the specified object `property` exists and is a direct property,
   * instead of an inherited property.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Object} object The object to check.
   * @param {string} property The property to check for.
   * @returns {boolean} Returns `true` if key is a direct property, else `false`.
   * @example
   *
   * _.has({ 'a': 1, 'b': 2, 'c': 3 }, 'b');
   * // => true
   */
  function has(object, property) {
    return object ? hasOwnProperty.call(object, property) : false;
  }

  /**
   * Creates an object composed of the inverted keys and values of the given object.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Object} object The object to invert.
   * @returns {Object} Returns the created inverted object.
   * @example
   *
   *  _.invert({ 'first': 'moe', 'second': 'larry' });
   * // => { 'moe': 'first', 'larry': 'second' }
   */
  function invert(object) {
    var index = -1,
        props = keys(object),
        length = props.length,
        result = {};

    while (++index < length) {
      var key = props[index];
      result[object[key]] = key;
    }
    return result;
  }

  /**
   * Checks if `value` is a boolean value.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if the `value` is a boolean value, else `false`.
   * @example
   *
   * _.isBoolean(null);
   * // => false
   */
  function isBoolean(value) {
    return value === true || value === false || toString.call(value) == boolClass;
  }

  /**
   * Checks if `value` is a date.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if the `value` is a date, else `false`.
   * @example
   *
   * _.isDate(new Date);
   * // => true
   */
  function isDate(value) {
    return value ? (typeof value == 'object' && toString.call(value) == dateClass) : false;
  }

  /**
   * Checks if `value` is a DOM element.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if the `value` is a DOM element, else `false`.
   * @example
   *
   * _.isElement(document.body);
   * // => true
   */
  function isElement(value) {
    return value ? value.nodeType === 1 : false;
  }

  /**
   * 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".
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Array|Object|string} value The value to inspect.
   * @returns {boolean} Returns `true` if the `value` is empty, else `false`.
   * @example
   *
   * _.isEmpty([1, 2, 3]);
   * // => false
   *
   * _.isEmpty({});
   * // => true
   *
   * _.isEmpty('');
   * // => true
   */
  function isEmpty(value) {
    if (!value) {
      return true;
    }
    if (isArray(value) || isString(value)) {
      return !value.length;
    }
    for (var key in value) {
      if (hasOwnProperty.call(value, key)) {
        return false;
      }
    }
    return true;
  }

  /**
   * 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).
   *
   * @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`.
   * @example
   *
   * var moe = { 'name': 'moe', 'age': 40 };
   * var copy = { 'name': 'moe', 'age': 40 };
   *
   * moe == copy;
   * // => false
   *
   * _.isEqual(moe, copy);
   * // => true
   *
   * var words = ['hello', 'goodbye'];
   * var otherWords = ['hi', 'goodbye'];
   *
   * _.isEqual(words, otherWords, function(a, b) {
   *   var reGreet = /^(?:hello|hi)$/i,
   *       aGreet = _.isString(a) && reGreet.test(a),
   *       bGreet = _.isString(b) && reGreet.test(b);
   *
   *   return (aGreet || bGreet) ? (aGreet == bGreet) : undefined;
   * });
   * // => true
   */
  function isEqual(a, b) {
    return baseIsEqual(a, b);
  }

  /**
   * Checks if `value` is, or can be coerced to, a finite number.
   *
   * 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.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if the `value` is finite, else `false`.
   * @example
   *
   * _.isFinite(-101);
   * // => true
   *
   * _.isFinite('10');
   * // => true
   *
   * _.isFinite(true);
   * // => false
   *
   * _.isFinite('');
   * // => false
   *
   * _.isFinite(Infinity);
   * // => false
   */
  function isFinite(value) {
    return nativeIsFinite(value) && !nativeIsNaN(parseFloat(value));
  }

  /**
   * Checks if `value` is a function.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if the `value` is a function, else `false`.
   * @example
   *
   * _.isFunction(_);
   * // => true
   */
  function isFunction(value) {
    return typeof value == 'function';
  }
  // fallback for older versions of Chrome and Safari
  if (isFunction(/x/)) {
    isFunction = function(value) {
      return typeof value == 'function' && toString.call(value) == funcClass;
    };
  }

  /**
   * Checks if `value` is the language type of Object.
   * (e.g. arrays, functions, objects, regexes, `new Number(0)`, and `new String('')`)
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if the `value` is an object, else `false`.
   * @example
   *
   * _.isObject({});
   * // => true
   *
   * _.isObject([1, 2, 3]);
   * // => true
   *
   * _.isObject(1);
   * // => false
   */
  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]);
  }

  /**
   * Checks if `value` is `NaN`.
   *
   * 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.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if the `value` is `NaN`, else `false`.
   * @example
   *
   * _.isNaN(NaN);
   * // => true
   *
   * _.isNaN(new Number(NaN));
   * // => true
   *
   * isNaN(undefined);
   * // => true
   *
   * _.isNaN(undefined);
   * // => false
   */
  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;
  }

  /**
   * Checks if `value` is `null`.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if the `value` is `null`, else `false`.
   * @example
   *
   * _.isNull(null);
   * // => true
   *
   * _.isNull(undefined);
   * // => false
   */
  function isNull(value) {
    return value === null;
  }

  /**
   * Checks if `value` is a number.
   *
   * Note: `NaN` is considered a number. See http://es5.github.io/#x8.5.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if the `value` is a number, else `false`.
   * @example
   *
   * _.isNumber(8.4 * 5);
   * // => true
   */
  function isNumber(value) {
    return typeof value == 'number' || toString.call(value) == numberClass;
  }

  /**
   * Checks if `value` is a regular expression.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if the `value` is a regular expression, else `false`.
   * @example
   *
   * _.isRegExp(/moe/);
   * // => true
   */
  function isRegExp(value) {
    return (value && objectTypes[typeof value]) ? toString.call(value) == regexpClass : false;
  }

  /**
   * Checks if `value` is a string.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if the `value` is a string, else `false`.
   * @example
   *
   * _.isString('moe');
   * // => true
   */
  function isString(value) {
    return typeof value == 'string' || toString.call(value) == stringClass;
  }

  /**
   * Checks if `value` is `undefined`.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if the `value` is `undefined`, else `false`.
   * @example
   *
   * _.isUndefined(void 0);
   * // => true
   */
  function isUndefined(value) {
    return typeof value == 'undefined';
  }

  /**
   * 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).
   *
   * @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.
   * @example
   *
   * _.omit({ 'name': 'moe', 'age': 40 }, 'age');
   * // => { 'name': 'moe' }
   *
   * _.omit({ 'name': 'moe', 'age': 40 }, function(value) {
   *   return typeof value == 'number';
   * });
   * // => { 'name': 'moe' }
   */
  function omit(object) {
    var indexOf = getIndexOf(),
        props = baseFlatten(arguments, true, false, 1),
        result = {};

    forIn(object, function(value, key) {
      if (indexOf(props, key) < 0) {
        result[key] = value;
      }
    });
    return result;
  }

  /**
   * Creates a two dimensional array of an object's key-value pairs,
   * i.e. `[[key1, value1], [key2, value2]]`.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Object} object The object to inspect.
   * @returns {Array} Returns new array of key-value pairs.
   * @example
   *
   * _.pairs({ 'moe': 30, 'larry': 40 });
   * // => [['moe', 30], ['larry', 40]] (property order is not guaranteed across environments)
   */
  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]];
    }
    return result;
  }

  /**
   * 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).
   *
   * @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.
   * @example
   *
   * _.pick({ 'name': 'moe', '_userid': 'moe1' }, 'name');
   * // => { 'name': 'moe' }
   *
   * _.pick({ 'name': 'moe', '_userid': 'moe1' }, function(value, key) {
   *   return key.charAt(0) != '_';
   * });
   * // => { 'name': 'moe' }
   */
  function pick(object) {
    var index = -1,
        props = baseFlatten(arguments, true, false, 1),
        length = props.length,
        result = {};

    while (++index < length) {
      var prop = props[index];
      if (prop in object) {
        result[prop] = object[prop];
      }
    }
    return result;
  }

  /**
   * Creates an array composed of the own enumerable property values of `object`.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Object} object The object to inspect.
   * @returns {Array} Returns an array of property values.
   * @example
   *
   * _.values({ 'one': 1, 'two': 2, 'three': 3 });
   * // => [1, 2, 3] (property order is not guaranteed across environments)
   */
  function values(object) {
    var index = -1,
        props = keys(object),
        length = props.length,
        result = Array(length);

    while (++index < length) {
      result[index] = object[props[index]];
    }
    return result;
  }

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

  /**
   * 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.
   *
   * @static
   * @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`.
   * @example
   *
   * _.contains([1, 2, 3], 1);
   * // => true
   *
   * _.c