threejs-boilerplate/node_modules/yeoman-generator/test/fixtures/lodash-copy.js

/*!
 * Lo-Dash v0.7.0 <http://lodash.com>
 * Copyright 2012 John-David Dalton <http://allyoucanleet.com/>
 * Based on Underscore.js 1.3.3, copyright 2009-2012 Jeremy Ashkenas, DocumentCloud Inc.
 * <http://documentcloud.github.com/underscore>
 * Available under MIT license <http://lodash.com/license>
 */
;(function(window, undefined) {
  'use strict';

  /** Detect free variable `exports` */
  var freeExports = typeof exports == 'object' && exports &&
    (typeof global == 'object' && global && global == global.global && (window = global), exports);

  /** Native prototype shortcuts */
  var ArrayProto = Array.prototype,
      BoolProto = Boolean.prototype,
      ObjectProto = Object.prototype,
      NumberProto = Number.prototype,
      StringProto = String.prototype;

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

  /** Used by `cachedContains` as the default size when optimizations are enabled for large arrays */
  var largeArraySize = 30;

  /** Used to restore the original `_` reference in `noConflict` */
  var oldDash = window._;

  /** Used to detect delimiter values that should be processed by `tokenizeEvaluate` */
  var reComplexDelimiter = /[-?+=!~*%&^<>|{(\/]|\[\D|\b(?:delete|in|instanceof|new|typeof|void)\b/;

  /** Used to match HTML entities */
  var reEscapedHtml = /&(?:amp|lt|gt|quot|#x27);/g;

  /** 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 regexp flags from their coerced string values */
  var reFlags = /\w*$/;

  /** Used to insert the data object variable into compiled template source */
  var reInsertVariable = /(?:__e|__t = )\(\s*(?![\d\s"']|this\.)/g;

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

  /** Used to ensure capturing order and avoid matches for undefined delimiters */
  var reNoMatch = /($^)/;

  /** Used to match HTML characters */
  var reUnescapedHtml = /[&<>"']/g;

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

  /** Used to fix the JScript [[DontEnum]] bug */
  var shadowed = [
    'constructor', 'hasOwnProperty', 'isPrototypeOf', 'propertyIsEnumerable',
    'toLocaleString', 'toString', 'valueOf'
  ];

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

  /** Native method shortcuts */
  var concat = ArrayProto.concat,
      hasOwnProperty = ObjectProto.hasOwnProperty,
      push = ArrayProto.push,
      propertyIsEnumerable = ObjectProto.propertyIsEnumerable,
      slice = ArrayProto.slice,
      toString = ObjectProto.toString;

  /* Native method shortcuts for methods with the same name as other `lodash` methods */
  var nativeBind = reNative.test(nativeBind = slice.bind) && nativeBind,
      nativeFloor = Math.floor,
      nativeIsArray = reNative.test(nativeIsArray = Array.isArray) && nativeIsArray,
      nativeIsFinite = window.isFinite,
      nativeKeys = reNative.test(nativeKeys = Object.keys) && nativeKeys,
      nativeMax = Math.max,
      nativeMin = Math.min,
      nativeRandom = Math.random;

  /** `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]';

  /** Timer shortcuts */
  var clearTimeout = window.clearTimeout,
      setTimeout = window.setTimeout;

  /**
   * Detect the JScript [[DontEnum]] bug:
   *
   * In IE < 9 an objects own properties, shadowing non-enumerable ones, are
   * made non-enumerable as well.
   */
  var hasDontEnumBug;

  /**
   * Detect if `Array#shift` and `Array#splice` augment array-like objects
   * incorrectly:
   *
   * 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.
   */
  var hasObjectSpliceBug;

  /** Detect if own properties are iterated after inherited properties (IE < 9) */
  var iteratesOwnLast;

  /** Detect if an `arguments` object's indexes are non-enumerable (IE < 9) */
  var noArgsEnum = true;

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

    function ctor() { this.x = 1; }
    ctor.prototype = { 'valueOf': 1, 'y': 1 };
    for (var prop in new ctor) { props.push(prop); }
    for (prop in arguments) { noArgsEnum = !prop; }

    hasDontEnumBug = (props + '').length < 4;
    iteratesOwnLast = props[0] != 'x';
    hasObjectSpliceBug = (props.splice.call(object, 0, 1), object[0]);
  }(1));

  /** Detect if an `arguments` object's [[Class]] is unresolvable (Firefox < 4, IE < 9) */
  var noArgsClass = !isArguments(arguments);

  /** Detect if `Array#slice` cannot be used to convert strings to arrays (Opera < 10.52) */
  var noArraySliceOnStrings = slice.call('x')[0] != 'x';

  /**
   * Detect lack of support for accessing string characters by index:
   *
   * IE < 8 can't access characters by index and IE 8 can only access
   * characters by index on string literals.
   */
  var noCharByIndex = ('x'[0] + Object('x')[0]) != 'xx';

  /**
   * Detect if a node's [[Class]] is unresolvable (IE < 9)
   * and that the JS engine won't error when attempting to coerce an object to
   * a string without a `toString` property value of `typeof` "function".
   */
  try {
    var noNodeClass = ({ 'toString': 0 } + '', toString.call(window.document || 0) == objectClass);
  } catch(e) { }

  /* Detect if `Function#bind` exists and is inferred to be fast (all but V8) */
  var isBindFast = nativeBind && /\n|Opera/.test(nativeBind + toString.call(window.opera));

  /* Detect if `Object.keys` exists and is inferred to be fast (IE, Opera, V8) */
  var isKeysFast = nativeKeys && /^.+$|true/.test(nativeKeys + !!window.attachEvent);

  /* Detect if strict mode, "use strict", is inferred to be fast (V8) */
  var isStrictFast = !isBindFast;

  /**
   * Detect if sourceURL syntax is usable without erroring:
   *
   * The JS engine in Adobe products, like InDesign, will throw a syntax error
   * when it encounters a single line comment beginning with the `@` symbol.
   *
   * The JS engine in Narwhal will generate the function `function anonymous(){//}`
   * and throw a syntax error.
   *
   * Avoid comments beginning `@` symbols in IE because they are part of its
   * non-standard conditional compilation support.
   * http://msdn.microsoft.com/en-us/library/121hztk3(v=vs.94).aspx
   */
  try {
    var useSourceURL = (Function('//@')(), !window.attachEvent);
  } catch(e) { }

  /** Used to identify object classifications that are array-like */
  var arrayLikeClasses = {};
  arrayLikeClasses[boolClass] = arrayLikeClasses[dateClass] = arrayLikeClasses[funcClass] =
  arrayLikeClasses[numberClass] = arrayLikeClasses[objectClass] = arrayLikeClasses[regexpClass] = false;
  arrayLikeClasses[argsClass] = arrayLikeClasses[arrayClass] = arrayLikeClasses[stringClass] = true;

  /** Used to identify object classifications that `_.clone` supports */
  var cloneableClasses = {};
  cloneableClasses[argsClass] = cloneableClasses[funcClass] = false;
  cloneableClasses[arrayClass] = cloneableClasses[boolClass] = cloneableClasses[dateClass] =
  cloneableClasses[numberClass] = cloneableClasses[objectClass] = cloneableClasses[regexpClass] =
  cloneableClasses[stringClass] = true;

  /**
   * 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 = {
    '&amp;': '&',
    '&lt;': '<',
    '&gt;': '>',
    '&quot;': '"',
    '&#x27;': "'"
  };

  /** 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,
    'unknown': true
  };

  /** Used to escape characters for inclusion in compiled string literals */
  var stringEscapes = {
    '\\': '\\',
    "'": "'",
    '\n': 'n',
    '\r': 'r',
    '\t': 't',
    '\u2028': 'u2028',
    '\u2029': 'u2029'
  };

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

  /**
   * The `lodash` function.
   *
   * @name _
   * @constructor
   * @param {Mixed} value The value to wrap in a `LoDash` instance.
   * @returns {Object} Returns a `LoDash` instance.
   */
  function lodash(value) {
    // allow invoking `lodash` without the `new` operator
    return new LoDash(value);
  }

  /**
   * Creates a `LoDash` instance that wraps a value to allow chaining.
   *
   * @private
   * @constructor
   * @param {Mixed} value The value to wrap.
   */
  function LoDash(value) {
    // exit early if already wrapped
    if (value && value.__wrapped__) {
      return value;
    }
    this.__wrapped__ = value;
  }

  /**
   * 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.
     *
     * @static
     * @memberOf _.templateSettings
     * @type RegExp
     */
    'escape': /<%-([\s\S]+?)%>/g,

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

    /**
     * Used to detect `data` property values to inject.
     *
     * @static
     * @memberOf _.templateSettings
     * @type RegExp
     */
    'interpolate': /<%=([\s\S]+?)%>/g,

    /**
     * Used to reference the data object in the template text.
     *
     * @static
     * @memberOf _.templateSettings
     * @type String
     */
    'variable': ''
  };

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

  /**
   * The template used to create iterator functions.
   *
   * @private
   * @param {Obect} data The data object used to populate the text.
   * @returns {String} Returns the interpolated text.
   */
  var iteratorTemplate = template(
    // conditional strict mode
    '<% if (useStrict) { %>\'use strict\';\n<% } %>' +

    // the `iteratee` may be reassigned by the `top` snippet
    'var index, value, iteratee = <%= firstArg %>, ' +
    // assign the `result` variable an initial value
    'result<% if (init) { %> = <%= init %><% } %>;\n' +
    // add code to exit early or do so if the first argument is falsey
    '<%= exit %>;\n' +
    // add code after the exit snippet but before the iteration branches
    '<%= top %>;\n' +

    // the following branch is for iterating arrays and array-like objects
    '<% if (arrayBranch) { %>' +
    'var length = iteratee.length; index = -1;' +
    '  <% if (objectBranch) { %>\nif (length === +length) {<% } %>' +

    // add support for accessing string characters by index if needed
    '  <% if (noCharByIndex) { %>\n' +
    '  if (toString.call(iteratee) == stringClass) {\n' +
    '    iteratee = iteratee.split(\'\')\n' +
    '  }' +
    '  <% } %>\n' +

    '  <%= arrayBranch.beforeLoop %>;\n' +
    '  while (++index < length) {\n' +
    '    value = iteratee[index];\n' +
    '    <%= arrayBranch.inLoop %>\n' +
    '  }' +
    '  <% if (objectBranch) { %>\n}<% } %>' +
    '<% } %>' +

    // the following branch is for iterating an object's own/inherited properties
    '<% if (objectBranch) { %>' +
    '  <% if (arrayBranch) { %>\nelse {' +

    // add support for iterating over `arguments` objects if needed
    '  <%  } else if (noArgsEnum) { %>\n' +
    '  var length = iteratee.length; index = -1;\n' +
    '  if (length && isArguments(iteratee)) {\n' +
    '    while (++index < length) {\n' +
    '      value = iteratee[index += \'\'];\n' +
    '      <%= objectBranch.inLoop %>\n' +
    '    }\n' +
    '  } else {' +
    '  <% } %>' +

    // Firefox < 3.6, Opera > 9.50 - Opera < 11.60, and Safari < 5.1
    // (if the prototype or a property on the prototype has been set)
    // incorrectly sets a function's `prototype` property [[Enumerable]]
    // value to `true`. Because of this Lo-Dash standardizes on skipping
    // the the `prototype` property of functions regardless of its
    // [[Enumerable]] value.
    '  <% if (!hasDontEnumBug) { %>\n' +
    '  var skipProto = typeof iteratee == \'function\' && \n' +
    '    propertyIsEnumerable.call(iteratee, \'prototype\');\n' +
    '  <% } %>' +

    // iterate own properties using `Object.keys` if it's fast
    '  <% if (isKeysFast && useHas) { %>\n' +
    '  var ownIndex = -1,\n' +
    '      ownProps = objectTypes[typeof iteratee] ? nativeKeys(iteratee) : [],\n' +
    '      length = ownProps.length;\n\n' +
    '  <%= objectBranch.beforeLoop %>;\n' +
    '  while (++ownIndex < length) {\n' +
    '    index = ownProps[ownIndex];\n' +
    '    <% if (!hasDontEnumBug) { %>if (!(skipProto && index == \'prototype\')) {\n  <% } %>' +
    '    value = iteratee[index];\n' +
    '    <%= objectBranch.inLoop %>\n' +
    '    <% if (!hasDontEnumBug) { %>}\n<% } %>' +
    '  }' +

    // else using a for-in loop
    '  <% } else { %>\n' +
    '  <%= objectBranch.beforeLoop %>;\n' +
    '  for (index in iteratee) {<%' +
    '    if (!hasDontEnumBug || useHas) { %>\n    if (<%' +
    '      if (!hasDontEnumBug) { %>!(skipProto && index == \'prototype\')<% }' +
    '      if (!hasDontEnumBug && useHas) { %> && <% }' +
    '      if (useHas) { %>hasOwnProperty.call(iteratee, index)<% }' +
    '    %>) {' +
    '    <% } %>\n' +
    '    value = iteratee[index];\n' +
    '    <%= objectBranch.inLoop %>;' +
    '    <% if (!hasDontEnumBug || useHas) { %>\n    }<% } %>\n' +
    '  }' +
    '  <% } %>' +

    // Because IE < 9 can't set the `[[Enumerable]]` attribute of an
    // existing property and the `constructor` property of a prototype
    // defaults to non-enumerable, Lo-Dash skips the `constructor`
    // property when it infers it's iterating over a `prototype` object.
    '  <% if (hasDontEnumBug) { %>\n\n' +
    '  var ctor = iteratee.constructor;\n' +
    '    <% for (var k = 0; k < 7; k++) { %>\n' +
    '  index = \'<%= shadowed[k] %>\';\n' +
    '  if (<%' +
    '      if (shadowed[k] == \'constructor\') {' +
    '        %>!(ctor && ctor.prototype === iteratee) && <%' +
    '      } %>hasOwnProperty.call(iteratee, index)) {\n' +
    '    value = iteratee[index];\n' +
    '    <%= objectBranch.inLoop %>\n' +
    '  }' +
    '    <% } %>' +
    '  <% } %>' +
    '  <% if (arrayBranch || noArgsEnum) { %>\n}<% } %>' +
    '<% } %>\n' +

    // add code to the bottom of the iteration function
    '<%= bottom %>;\n' +
    // finally, return the `result`
    'return result'
  );

  /**
   * Reusable iterator options shared by
   * `every`, `filter`, `find`, `forEach`, `forIn`, `forOwn`, `groupBy`, `map`,
   * `reject`, `some`, and `sortBy`.
   */
  var baseIteratorOptions = {
    'args': 'collection, callback, thisArg',
    'init': 'collection',
    'top':
      'if (!callback) {\n' +
      '  callback = identity\n' +
      '}\n' +
      'else if (thisArg) {\n' +
      '  callback = bindIterator(callback, thisArg)\n' +
      '}',
    'inLoop': 'if (callback(value, index, collection) === false) return result'
  };

  /** Reusable iterator options for `countBy`, `groupBy`, and `sortBy` */
  var countByIteratorOptions = {
    'init': '{}',
    'top':
      'var prop;\n' +
      'if (typeof callback != \'function\') {\n' +
      '  var valueProp = callback;\n' +
      '  callback = function(value) { return value[valueProp] }\n' +
      '}\n' +
      'else if (thisArg) {\n' +
      '  callback = bindIterator(callback, thisArg)\n' +
      '}',
    'inLoop':
      'prop = callback(value, index, collection);\n' +
      '(hasOwnProperty.call(result, prop) ? result[prop]++ : result[prop] = 1)'
  };

  /** Reusable iterator options for `every` and `some` */
  var everyIteratorOptions = {
    'init': 'true',
    'inLoop': 'if (!callback(value, index, collection)) return !result'
  };

  /** Reusable iterator options for `defaults` and `extend` */
  var extendIteratorOptions = {
    'useHas': false,
    'useStrict': false,
    'args': 'object',
    'init': 'object',
    'top':
      'for (var argsIndex = 1, argsLength = arguments.length; argsIndex < argsLength; argsIndex++) {\n' +
      '  if (iteratee = arguments[argsIndex]) {',
    'inLoop': 'result[index] = value',
    'bottom': '  }\n}'
  };

  /** Reusable iterator options for `filter`, `reject`, and `where` */
  var filterIteratorOptions = {
    'init': '[]',
    'inLoop': 'callback(value, index, collection) && result.push(value)'
  };

  /** Reusable iterator options for `find`, `forEach`, `forIn`, and `forOwn` */
  var forEachIteratorOptions = {
    'top': 'if (thisArg) callback = bindIterator(callback, thisArg)'
  };

  /** Reusable iterator options for `forIn` and `forOwn` */
  var forOwnIteratorOptions = {
    'inLoop': {
      'object': baseIteratorOptions.inLoop
    }
  };

  /** Reusable iterator options for `invoke`, `map`, `pluck`, and `sortBy` */
  var mapIteratorOptions = {
    'init': '',
    'exit': 'if (!collection) return []',
    'beforeLoop': {
      'array':  'result = Array(length)',
      'object': 'result = ' + (isKeysFast ? 'Array(length)' : '[]')
    },
    'inLoop': {
      'array':  'result[index] = callback(value, index, collection)',
      'object': 'result' + (isKeysFast ? '[ownIndex] = ' : '.push') + '(callback(value, index, collection))'
    }
  };

  /** Reusable iterator options for `omit` and `pick` */
  var omitIteratorOptions = {
    'useHas': false,
    'args': 'object, callback, thisArg',
    'init': '{}',
    'top':
      'var isFunc = typeof callback == \'function\';\n' +
      'if (!isFunc) {\n' +
      '  var props = concat.apply(ArrayProto, arguments)\n' +
      '} else if (thisArg) {\n' +
      '  callback = bindIterator(callback, thisArg)\n' +
      '}',
    'inLoop':
      'if (isFunc\n' +
      '  ? !callback(value, index, object)\n' +
      '  : indexOf(props, index) < 0\n' +
      ') result[index] = value'
  };

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

  /**
   * Creates a bound iterator function that, when called, invokes `func` with
   * the `this` binding of `thisArg` and the arguments (value, index, object).
   *
   * @private
   * @param {Function} func The function to bind.
   * @param {Mixed} [thisArg] The `this` binding of `func`.
   * @returns {Function} Returns the new bound function.
   */
  function bindIterator(func, thisArg) {
    return function(value, index, object) {
      return func.call(thisArg, value, index, object);
    };
  }

  /**
   * Creates a function optimized for searching large arrays for a given `value`,
   * starting at `fromIndex`, using strict equality for comparisons, i.e. `===`.
   *
   * @private
   * @param {Array} array The array to search.
   * @param {Mixed} value The value to search for.
   * @param {Number} [fromIndex=0] The index to start searching from.
   * @param {Number} [largeSize=30] The length at which an array is considered large.
   * @returns {Boolean} Returns `true` if `value` is found, else `false`.
   */
  function cachedContains(array, fromIndex, largeSize) {
    fromIndex || (fromIndex = 0);

    var length = array.length,
        isLarge = (length - fromIndex) >= (largeSize || largeArraySize),
        cache = isLarge ? {} : array;

    if (isLarge) {
      // init value cache
      var key,
          index = fromIndex - 1;

      while (++index < length) {
        // manually coerce `value` to string because `hasOwnProperty`, in some
        // older versions of Firefox, coerces objects incorrectly
        key = array[index] + '';
        (hasOwnProperty.call(cache, key) ? cache[key] : (cache[key] = [])).push(array[index]);
      }
    }
    return function(value) {
      if (isLarge) {
        var key = value + '';
        return hasOwnProperty.call(cache, key) && indexOf(cache[key], value) > -1;
      }
      return indexOf(cache, value, fromIndex) > -1;
    }
  }

  /**
   * Used by `sortBy` to compare transformed `collection` values, 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 ai = a.index,
        bi = b.index;

    a = a.criteria;
    b = b.criteria;

    // ensure a stable sort in V8 and other engines
    // http://code.google.com/p/v8/issues/detail?id=90
    if (a !== b) {
      if (a > b || a === undefined) {
        return 1;
      }
      if (a < b || b === undefined) {
        return -1;
      }
    }
    return ai < bi ? -1 : 1;
  }

  /**
   * Creates a function that, when called, invokes `func` with the `this`
   * binding of `thisArg` and prepends any `partailArgs` to the arguments passed
   * to the bound function.
   *
   * @private
   * @param {Function|String} func The function to bind or the method name.
   * @param {Mixed} [thisArg] The `this` binding of `func`.
   * @param {Array} partialArgs An array of arguments to be partially applied.
   * @returns {Function} Returns the new bound function.
   */
  function createBound(func, thisArg, partialArgs) {
    var isFunc = isFunction(func),
        isPartial = !partialArgs,
        methodName = func;

    // juggle arguments
    if (isPartial) {
      partialArgs = thisArg;
    }

    function bound() {
      // `Function#bind` spec
      // http://es5.github.com/#x15.3.4.5
      var args = arguments,
          thisBinding = isPartial ? this : thisArg;

      if (!isFunc) {
        func = thisArg[methodName];
      }
      if (partialArgs.length) {
        args = args.length
          ? partialArgs.concat(slice.call(args))
          : partialArgs;
      }
      if (this instanceof bound) {
        // get `func` instance if `bound` is invoked in a `new` expression
        noop.prototype = func.prototype;
        thisBinding = new noop;

        // mimic the constructor's `return` behavior
        // http://es5.github.com/#x13.2.2
        var result = func.apply(thisBinding, args);
        return result && objectTypes[typeof result]
          ? result
          : thisBinding
      }
      return func.apply(thisBinding, args);
    }
    return bound;
  }

  /**
   * Creates compiled iteration functions. The iteration function will be created
   * to iterate over only objects if the first argument of `options.args` is
   * "object" or `options.inLoop.array` is falsey.
   *
   * @private
   * @param {Object} [options1, options2, ...] The compile options objects.
   *
   *  useHas - A boolean to specify whether or not to use `hasOwnProperty` checks
   *   in the object loop.
   *
   *  useStrict - A boolean to specify whether or not to include the ES5
   *   "use strict" directive.
   *
   *  args - A string of comma separated arguments the iteration function will
   *   accept.
   *
   *  init - A string to specify the initial value of the `result` variable.
   *
   *  exit - A string of code to use in place of the default exit-early check
   *   of `if (!arguments[0]) return result`.
   *
   *  top - A string of code to execute after the exit-early check but before
   *   the iteration branches.
   *
   *  beforeLoop - A string or object containing an "array" or "object" property
   *   of code to execute before the array or object loops.
   *
   *  inLoop - A string or object containing an "array" or "object" property
   *   of code to execute in the array or object loops.
   *
   *  bottom - A string of code to execute after the iteration branches but
   *   before the `result` is returned.
   *
   * @returns {Function} Returns the compiled function.
   */
  function createIterator() {
    var object,
        prop,
        value,
        index = -1,
        length = arguments.length;

    // merge options into a template data object
    var data = {
      'bottom': '',
      'exit': '',
      'init': '',
      'top': '',
      'arrayBranch': { 'beforeLoop': '' },
      'objectBranch': { 'beforeLoop': '' }
    };

    while (++index < length) {
      object = arguments[index];
      for (prop in object) {
        value = (value = object[prop]) == null ? '' : value;
        // keep this regexp explicit for the build pre-process
        if (/beforeLoop|inLoop/.test(prop)) {
          if (typeof value == 'string') {
            value = { 'array': value, 'object': value };
          }
          data.arrayBranch[prop] = value.array || '';
          data.objectBranch[prop] = value.object || '';
        } else {
          data[prop] = value;
        }
      }
    }
    // set additional template `data` values
    var args = data.args,
        firstArg = /^[^,]+/.exec(args)[0],
        useStrict = data.useStrict;

    data.firstArg = firstArg;
    data.hasDontEnumBug = hasDontEnumBug;
    data.isKeysFast = isKeysFast;
    data.noArgsEnum = noArgsEnum;
    data.shadowed = shadowed;
    data.useHas = data.useHas !== false;
    data.useStrict = useStrict == null ? isStrictFast : useStrict;

    if (data.noCharByIndex == null) {
      data.noCharByIndex = noCharByIndex;
    }
    if (!data.exit) {
      data.exit = 'if (!' + firstArg + ') return result';
    }
    if (firstArg != 'collection' || !data.arrayBranch.inLoop) {
      data.arrayBranch = null;
    }
    // create the function factory
    var factory = Function(
        'arrayLikeClasses, ArrayProto, bind, bindIterator, compareAscending, concat, ' +
        'forIn, hasOwnProperty, identity, indexOf, isArguments, isArray, isFunction, ' +
        'isPlainObject, objectClass, objectTypes, nativeKeys, propertyIsEnumerable, ' +
        'slice, stringClass, toString',
      'var callee = function(' + args + ') {\n' + iteratorTemplate(data) + '\n};\n' +
      'return callee'
    );
    // return the compiled function
    return factory(
      arrayLikeClasses, ArrayProto, bind, bindIterator, compareAscending, concat,
      forIn, hasOwnProperty, identity, indexOf, isArguments, isArray, isFunction,
      isPlainObject, objectClass, objectTypes, nativeKeys, propertyIsEnumerable,
      slice, stringClass, toString
    );
  }

  /**
   * 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];
  }

  /**
   * 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];
  }

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

  /**
   * 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 {Mixed} 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 toString.call(value) == argsClass;
  }
  // fallback for browsers that can't detect `arguments` objects by [[Class]]
  if (noArgsClass) {
    isArguments = function(value) {
      return !!(value && hasOwnProperty.call(value, 'callee'));
    };
  }

  /**
   * Checks if `value` is an array.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Mixed} 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 toString.call(value) == arrayClass;
  };

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

  /**
   * A fallback implementation of `isPlainObject` that 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 {Mixed} value The value to check.
   * @param {Boolean} [skipArgsCheck=false] Internally used to skip checks for
   *  `arguments` objects.
   * @returns {Boolean} Returns `true` if `value` is a plain object, else `false`.
   */
  function isPlainFallback(value, skipArgsCheck) {
    // avoid non-objects and false positives for `arguments` objects
    var result = false;
    if (!(value && typeof value == 'object') || (!skipArgsCheck && isArguments(value))) {
      return result;
    }
    // IE < 9 presents DOM nodes as `Object` objects except they have `toString`
    // methods that are `typeof` "string" and still can coerce nodes to strings.
    // Also check that the constructor is `Object` (i.e. `Object instanceof Object`)
    var ctor = value.constructor;
    if ((!noNodeClass || !(typeof value.toString != 'function' && typeof (value + '') == 'string')) &&
        (!isFunction(ctor) || ctor instanceof ctor)) {
      // IE < 9 iterates inherited properties before own properties. If the first
      // iterated property is an object's own property then there are no inherited
      // enumerable properties.
      if (iteratesOwnLast) {
        forIn(value, function(value, key, object) {
          result = !hasOwnProperty.call(object, key);
          return false;
        });
        return result === 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 result === false || hasOwnProperty.call(value, result);
    }
    return result;
  }

  /**
   * Checks if a given `value` is an object created by the `Object` constructor.
   *
   * @private
   * @param {Mixed} value The value to check.
   * @param {Boolean} [skipArgsCheck=false] Internally used to skip checks for
   *  `arguments` objects.
   * @returns {Boolean} Returns `true` if `value` is a plain object, else `false`.
   */
  var isPlainObject = objectTypes.__proto__ != ObjectProto ? isPlainFallback : function(value, skipArgsCheck) {
    if (!value) {
      return false;
    }
    var valueOf = value.valueOf,
        objProto = typeof valueOf == 'function' && (objProto = valueOf.__proto__) && objProto.__proto__;

    return objProto
      ? value == objProto || (value.__proto__ == objProto && (skipArgsCheck || !isArguments(value)))
      : isPlainFallback(value);
  };

  /**
   * A shim implementation of `Object.keys` that produces an array of the given
   * object's own enumerable property names.
   *
   * @private
   * @param {Object} object The object to inspect.
   * @returns {Array} Returns a new array of property names.
   */
  var shimKeys = createIterator({
    'args': 'object',
    'init': '[]',
    'inLoop': 'result.push(index)'
  });

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

  /**
   * Creates a clone of `value`. If `deep` is `true`, all nested objects will
   * also be cloned otherwise they will be assigned by reference. Functions, DOM
   * nodes, `arguments` objects, and objects created by constructors other than
   * `Object` are **not** cloned.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Mixed} value The value to clone.
   * @param {Boolean} deep A flag to indicate a deep clone.
   * @param {Object} [guard] Internally used to allow this method to work with
   *  others like `_.map` without using their callback `index` argument for `deep`.
   * @param {Array} [stackA=[]] Internally used to track traversed source objects.
   * @param {Array} [stackB=[]] Internally used to associate clones with their
   *  source counterparts.
   * @returns {Mixed} Returns the cloned `value`.
   * @example
   *
   * var stooges = [
   *   { 'name': 'moe', 'age': 40 },
   *   { 'name': 'larry', 'age': 50 },
   *   { 'name': 'curly', 'age': 60 }
   * ];
   *
   * _.clone({ 'name': 'moe' });
   * // => { 'name': 'moe' }
   *
   * var shallow = _.clone(stooges);
   * shallow[0] === stooges[0];
   * // => true
   *
   * var deep = _.clone(stooges, true);
   * shallow[0] === stooges[0];
   * // => false
   */
  function clone(value, deep, guard, stackA, stackB) {
    if (value == null) {
      return value;
    }
    if (guard) {
      deep = false;
    }
    // inspect [[Class]]
    var isObj = objectTypes[typeof value];
    if (isObj) {
      // don't clone `arguments` objects, functions, or non-object Objects
      var className = toString.call(value);
      if (!cloneableClasses[className] || (noArgsClass && isArguments(value))) {
        return value;
      }
      var isArr = className == arrayClass;
      isObj = isArr || (className == objectClass ? isPlainObject(value, true) : isObj);
    }
    // shallow clone
    if (!isObj || !deep) {
      // don't clone functions
      return isObj
        ? (isArr ? slice.call(value) : extend({}, value))
        : value;
    }

    var ctor = value.constructor;
    switch (className) {
      case boolClass:
        return new ctor(value == true);

      case dateClass:
        return new ctor(+value);

      case numberClass:
      case stringClass:
        return new ctor(value);

      case regexpClass:
        return ctor(value.source, reFlags.exec(value));
    }

    // check for circular references and return corresponding clone
    stackA || (stackA = []);
    stackB || (stackB = []);

    var length = stackA.length;
    while (length--) {
      if (stackA[length] == value) {
        return stackB[length];
      }
    }

    // init cloned object
    var result = isArr ? ctor(length = value.length) : {};

    // 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)
    if (isArr) {
      var index = -1;
      while (++index < length) {
        result[index] = clone(value[index], deep, null, stackA, stackB);
      }
    } else {
      forOwn(value, function(objValue, key) {
        result[key] = clone(objValue, deep, null, stackA, stackB);
      });
    }
    return result;
  }

  /**
   * Assigns enumerable properties of the default object(s) to the `destination`
   * object for all `destination` properties that resolve to `null`/`undefined`.
   * Once a property is set, additional defaults of the same property will be
   * ignored.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Object} object The destination object.
   * @param {Object} [default1, default2, ...] The default objects.
   * @returns {Object} Returns the destination object.
   * @example
   *
   * var iceCream = { 'flavor': 'chocolate' };
   * _.defaults(iceCream, { 'flavor': 'vanilla', 'sprinkles': 'rainbow' });
   * // => { 'flavor': 'chocolate', 'sprinkles': 'rainbow' }
   */
  var defaults = createIterator(extendIteratorOptions, {
    'inLoop': 'if (result[index] == null) ' + extendIteratorOptions.inLoop
  });

  /**
   * Assigns enumerable properties of the source object(s) to the `destination`
   * object. Subsequent sources will overwrite propery assignments of previous
   * sources.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Object} object The destination object.
   * @param {Object} [source1, source2, ...] The source objects.
   * @returns {Object} Returns the destination object.
   * @example
   *
   * _.extend({ 'name': 'moe' }, { 'age': 40 });
   * // => { 'name': 'moe', 'age': 40 }
   */
  var extend = createIterator(extendIteratorOptions);

  /**
   * Iterates over `object`'s own and inherited enumerable properties, 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 _
   * @category Objects
   * @param {Object} object The object to iterate over.
   * @param {Function} callback The function called per iteration.
   * @param {Mixed} [thisArg] The `this` binding for the callback.
   * @returns {Object} Returns `object`.
   * @example
   *
   * function Dog(name) {
   *   this.name = name;
   * }
   *
   * Dog.prototype.bark = function() {
   *   alert('Woof, woof!');
   * };
   *
   * _.forIn(new Dog('Dagny'), function(value, key) {
   *   alert(key);
   * });
   * // => alerts 'name' and 'bark' (order is not guaranteed)
   */
  var forIn = createIterator(baseIteratorOptions, forEachIteratorOptions, forOwnIteratorOptions, {
    'useHas': false
  });

  /**
   * Iterates over `object`'s own enumerable properties, 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 _
   * @category Objects
   * @param {Object} object The object to iterate over.
   * @param {Function} callback The function called per iteration.
   * @param {Mixed} [thisArg] The `this` binding for the callback.
   * @returns {Object} Returns `object`.
   * @example
   *
   * _.forOwn({ '0': 'zero', '1': 'one', 'length': 2 }, function(num, key) {
   *   alert(key);
   * });
   * // => alerts '0', '1', and 'length' (order is not guaranteed)
   */
  var forOwn = createIterator(baseIteratorOptions, forEachIteratorOptions, forOwnIteratorOptions);

  /**
   * Creates a sorted array 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 a new array of property names that have function values.
   * @example
   *
   * _.functions(_);
   * // => ['all', 'any', 'bind', 'bindAll', 'clone', 'compact', 'compose', ...]
   */
  var functions = createIterator({
    'useHas': false,
    'args': 'object',
    'init': '[]',
    'inLoop': 'if (isFunction(value)) result.push(index)',
    'bottom': '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', 'third': 'Curly' });
   * // => { 'Moe': 'first', 'Larry': 'second', 'Curly': 'third' } (order is not guaranteed)
   */
  var invert = createIterator({
    'args': 'object',
    'init': '{}',
    'inLoop': 'result[value] = index'
  });

  /**
   * Checks if `value` is a boolean (`true` or `false`) value.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Mixed} 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 {Mixed} 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 toString.call(value) == dateClass;
  }

  /**
   * Checks if `value` is a DOM element.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Mixed} 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
   */
  var isEmpty = createIterator({
    'args': 'value',
    'init': 'true',
    'top':
      'var className = toString.call(value),\n' +
      '    length = value.length;\n' +
      'if (arrayLikeClasses[className]' +
      (noArgsClass ? ' || isArguments(value)' : '') + ' ||\n' +
      '  (className == objectClass && length === +length &&\n' +
      '  isFunction(value.splice))' +
      ') return !length',
    'inLoop': {
      'object': 'return false'
    }
  });

  /**
   * Performs a deep comparison between two values to determine if they are
   * equivalent to each other.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Mixed} a The value to compare.
   * @param {Mixed} b The other value to compare.
   * @param {Object} [stackA=[]] Internally used track traversed `a` objects.
   * @param {Object} [stackB=[]] Internally used track traversed `b` objects.
   * @returns {Boolean} Returns `true` if the values are equvalent, else `false`.
   * @example
   *
   * var moe = { 'name': 'moe', 'luckyNumbers': [13, 27, 34] };
   * var clone = { 'name': 'moe', 'luckyNumbers': [13, 27, 34] };
   *
   * moe == clone;
   * // => false
   *
   * _.isEqual(moe, clone);
   * // => true
   */
  function isEqual(a, b, stackA, stackB) {
    // a strict comparison is necessary because `null == undefined`
    if (a == null || b == null) {
      return a === b;
    }
    // exit early for identical values
    if (a === b) {
      // treat `+0` vs. `-0` as not equal
      return a !== 0 || (1 / a == 1 / b);
    }
    // unwrap any LoDash wrapped values
    if (objectTypes[typeof a] || objectTypes[typeof b]) {
      a = a.__wrapped__ || a;
      b = b.__wrapped__ || b;
    }
    // compare [[Class]] names
    var className = toString.call(a);
    if (className != toString.call(b)) {
      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.com/#x15.10.6.4)
        // treat string primitives and their corresponding object instances as equal
        return a == b + '';
    }
    // exit early, in older browsers, if `a` is array-like but not `b`
    var isArr = arrayLikeClasses[className];
    if (noArgsClass && !isArr && (isArr = isArguments(a)) && !isArguments(b)) {
      return false;
    }
    // exit for functions and DOM nodes
    if (!isArr && (className != objectClass || (noNodeClass && (
        (typeof a.toString != 'function' && typeof (a + '') == 'string') ||
        (typeof b.toString != 'function' && typeof (b + '') == 'string'))))) {
      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.com/#x15.12.3)
    stackA || (stackA = []);
    stackB || (stackB = []);

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

    var index = -1,
        result = true,
        size = 0;

    // 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) {
      // compare lengths to determine if a deep comparison is necessary
      size = a.length;
      result = size == b.length;

      if (result) {
        // deep compare the contents, ignoring non-numeric properties
        while (size--) {
          if (!(result = isEqual(a[size], b[size], stackA, stackB))) {
            break;
          }
        }
      }
      return result;
    }

    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
        )) {
      return false;
    }
    // deep compare objects
    for (var prop in a) {
      if (hasOwnProperty.call(a, prop)) {
        // count the number of properties.
        size++;
        // deep compare each property value.
        if (!(hasOwnProperty.call(b, prop) && isEqual(a[prop], b[prop], stackA, stackB))) {
          return false;
        }
      }
    }
    // ensure both objects have the same number of properties
    for (prop in b) {
      // The JS engine in Adobe products, like InDesign, has a bug that causes
      // `!size--` to throw an error so it must be wrapped in parentheses.
      // https://github.com/documentcloud/underscore/issues/355
      if (hasOwnProperty.call(b, prop) && !(size--)) {
        // `size` will be `-1` if `b` has more properties than `a`
        return false;
      }
    }
    // handle JScript [[DontEnum]] bug
    if (hasDontEnumBug) {
      while (++index < 7) {
        prop = shadowed[index];
        if (hasOwnProperty.call(a, prop) &&
            !(hasOwnProperty.call(b, prop) && isEqual(a[prop], b[prop], stackA, stackB))) {
          return false;
        }
      }
    }
    return true;
  }

  /**
   * Checks if `value` is a finite number.
   *
   * Note: This is not the same as native `isFinite`, which will return true for
   * booleans and other values. See http://es5.github.com/#x15.1.2.5.
   *
   * @deprecated
   * @static
   * @memberOf _
   * @category Objects
   * @param {Mixed} value The value to check.
   * @returns {Boolean} Returns `true` if the `value` is a finite number, else `false`.
   * @example
   *
   * _.isFinite(-101);
   * // => true
   *
   * _.isFinite('10');
   * // => false
   *
   * _.isFinite(Infinity);
   * // => false
   */
  function isFinite(value) {
    return nativeIsFinite(value) && toString.call(value) == numberClass;
  }

  /**
   * 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 {Mixed} value The value to check.
   * @returns {Boolean} Returns `true` if the `value` is an object, else `false`.
   * @example
   *
   * _.isObject({});
   * // => true
   *
   * _.isObject(1);
   * // => false
   */
  function isObject(value) {
    // check if the value is the ECMAScript language type of Object
    // http://es5.github.com/#x8
    // and avoid a V8 bug
    // http://code.google.com/p/v8/issues/detail?id=2291
    return value ? objectTypes[typeof value] : false;
  }

  /**
   * Checks if `value` is `NaN`.
   *
   * Note: This is not the same as native `isNaN`, which will return true for
   * `undefined` and other values. See http://es5.github.com/#x15.1.2.4.
   *
   * @deprecated
   * @static
   * @memberOf _
   * @category Objects
   * @param {Mixed} 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 toString.call(value) == numberClass && value != +value
  }

  /**
   * Checks if `value` is `null`.
   *
   * @deprecated
   * @static
   * @memberOf _
   * @category Objects
   * @param {Mixed} 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.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Mixed} 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 toString.call(value) == numberClass;
  }

  /**
   * Checks if `value` is a regular expression.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Mixed} 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 toString.call(value) == regexpClass;
  }

  /**
   * Checks if `value` is a string.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Mixed} 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 toString.call(value) == stringClass;
  }

  /**
   * Checks if `value` is `undefined`.
   *
   * @deprecated
   * @static
   * @memberOf _
   * @category Objects
   * @param {Mixed} 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 value === undefined;
  }

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

    // avoid iterating over the `prototype` property
    if (type == 'function' && propertyIsEnumerable.call(object, 'prototype')) {
      return shimKeys(object);
    }
    return object && objectTypes[type]
      ? nativeKeys(object)
      : [];
  };

  /**
   * Merges enumerable properties of the source object(s) into the `destination`
   * object. Subsequent sources will overwrite propery assignments of previous
   * sources.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Object} object The destination object.
   * @param {Object} [source1, source2, ...] The source objects.
   * @param {Object} [indicator] Internally used to indicate that the `stack`
   *  argument is an array of traversed objects instead of another source object.
   * @param {Array} [stackA=[]] Internally used to track traversed source objects.
   * @param {Array} [stackB=[]] Internally used to associate clones with their
   *  source counterparts.
   * @returns {Object} Returns the destination object.
   * @example
   *
   * var stooges = [
   *   { 'name': 'moe' },
   *   { 'name': 'larry' }
   * ];
   *
   * var ages = [
   *   { 'age': 40 },
   *   { 'age': 50 }
   * ];
   *
   * _.merge(stooges, ages);
   * // => [{ 'name': 'moe', 'age': 40 }, { 'name': 'larry', 'age': 50 }]
   */
  var merge = createIterator(extendIteratorOptions, {
    'args': 'object, source, indicator',
    'top':
      'var argsLength, isArr, stackA, stackB,\n' +
      '    args = arguments, argsIndex = 0;\n' +
      'if (indicator == isPlainObject) {\n' +
      '  argsLength = 2;\n' +
      '  stackA = args[3];\n' +
      '  stackB = args[4]\n' +
      '} else {\n' +
      '  argsLength = args.length;\n' +
      '  stackA = [];\n' +
      '  stackB = []\n' +
      '}\n' +
      'while (++argsIndex < argsLength) {\n' +
      '  if (iteratee = args[argsIndex]) {',
    'inLoop':
      'if ((source = value) && ((isArr = isArray(source)) || isPlainObject(source))) {\n' +
      '  var found = false, stackLength = stackA.length;\n' +
      '  while (stackLength--) {\n' +
      '    if (found = stackA[stackLength] == source) break\n' +
      '  }\n' +
      '  if (found) {\n' +
      '    result[index] = stackB[stackLength]\n' +
      '  } else {\n' +
      '    stackA.push(source);\n' +
      '    stackB.push(value = (value = result[index]) && isArr\n' +
      '      ? (isArray(value) ? value : [])\n' +
      '      : (isPlainObject(value) ? value : {})\n' +
      '    );\n' +
      '    result[index] = callee(value, source, isPlainObject, stackA, stackB)\n' +
      '  }\n' +
      '} else if (source != null) {\n' +
      '  result[index] = source\n' +
      '}'
  });

  /**
   * 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 `callback` is passed, it will be executed for each property
   * in the `object`, omitting the properties `callback` returns truthy 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} callback|[prop1, prop2, ...] The properties to omit
   *  or the function called per iteration.
   * @param {Mixed} [thisArg] The `this` binding for the callback.
   * @returns {Object} Returns an object without the omitted properties.
   * @example
   *
   * _.omit({ 'name': 'moe', 'age': 40, 'userid': 'moe1' }, 'userid');
   * // => { 'name': 'moe', 'age': 40 }
   *
   * _.omit({ 'name': 'moe', '_hint': 'knucklehead', '_seed': '96c4eb' }, function(value, key) {
   *   return key.charAt(0) == '_';
   * });
   * // => { 'name': 'moe' }
   */
  var omit = createIterator(omitIteratorOptions);

  /**
   * Creates a two dimensional array of the given 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, 'curly': 50 });
   * // => [['moe', 30], ['larry', 40], ['curly', 50]] (order is not guaranteed)
   */
  var pairs = createIterator({
    'args': 'object',
    'init':'[]',
    'inLoop': 'result'  + (isKeysFast ? '[ownIndex] = ' : '.push') + '([index, value])'
  });

  /**
   * 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 `callback` is passed, it will be executed for each property
   * in the `object`, picking the properties `callback` returns truthy 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} callback|[prop1, prop2, ...] The properties to pick
   *  or the function called per iteration.
   * @param {Mixed} [thisArg] The `this` binding for the callback.
   * @returns {Object} Returns an object composed of the picked properties.
   * @example
   *
   * _.pick({ 'name': 'moe', 'age': 40, 'userid': 'moe1' }, 'name', 'age');
   * // => { 'name': 'moe', 'age': 40 }
   *
   * _.pick({ 'name': 'moe', '_hint': 'knucklehead', '_seed': '96c4eb' }, function(value, key) {
   *   return key.charAt(0) != '_';
   * });
   * // => { 'name': 'moe' }
   */
  var pick = createIterator(omitIteratorOptions, {
    'top':
      'if (typeof callback != \'function\') {\n' +
      '  var prop,\n' +
      '      props = concat.apply(ArrayProto, arguments),\n' +
      '      length = props.length;\n' +
      '  for (index = 1; index < length; index++) {\n' +
      '    prop = props[index];\n' +
      '    if (prop in object) result[prop] = object[prop]\n' +
      '  }\n' +
      '} else {\n' +
      '  if (thisArg) callback = bindIterator(callback, thisArg)',
    'inLoop':
      'if (callback(value, index, object)) result[index] = value',
    'bottom': '}'
  });

  /**
   * 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 a new array of property values.
   * @example
   *
   * _.values({ 'one': 1, 'two': 2, 'three': 3 });
   * // => [1, 2, 3]
   */
  var values = createIterator({
    'args': 'object',
    'init': '[]',
    'inLoop': 'result.push(value)'
  });

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

  /**
   * Checks if a given `target` element is present in a `collection` using strict
   * equality for comparisons, i.e. `===`.
   *
   * @static
   * @memberOf _
   * @alias include
   * @category Collections
   * @param {Array|Object|String} collection The collection to iterate over.
   * @param {Mixed} target The value to check for.
   * @returns {Boolean} Returns `true` if the `target` element is found, else `false`.
   * @example
   *
   * _.contains([1, 2, 3], 3);
   * // => true
   *
   * _.contains({ 'name': 'moe', 'age': 40 }, 'moe');
   * // => true
   *
   * _.contains('curly', 'ur');
   * // => true
   */
  var contains = createIterator({
    'args': 'collection, target',
    'init': 'false',
    'noCharByIndex': false,
    'beforeLoop': {
      'array': 'if (toString.call(collection) == stringClass) return collection.indexOf(target) > -1'
    },
    'inLoop': 'if (value === target) return true'
  });

  /**
   * Creates an object composed of keys returned from running each element of
   * `collection` through a `callback`. The corresponding value of each key is
   * the number of times the key was returned by `callback`. The `callback` is
   * bound to `thisArg` and invoked with three arguments; (value, index|key, collection).
   * The `callback` argument may also be the name of a property to count by (e.g. 'length').
   *
   * @static
   * @memberOf _
   * @category Collections
   * @param {Array|Object|String} collection The collection to iterate over.
   * @param {Function|String} callback|property The function called per iteration
   *  or property name to count by.
   * @param {Mixed} [thisArg] The `this` binding for the callback.
   * @returns {Object} Returns the composed aggregate object.
   * @example
   *
   * _.countBy([4.3, 6.1, 6.4], function(num) { return Math.floor(num); });
   * // => { '4': 1, '6': 2 }
   *
   * _.countBy([4.3, 6.1, 6.4], function(num) { return this.floor(num); }, Math);
   * // => { '4': 1, '6': 2 }
   *
   * _.countBy(['one', 'two', 'three'], 'length');
   * // => { '3': 2, '5': 1 }
   */
  var countBy = createIterator(baseIteratorOptions, countByIteratorOptions);

  /**
   * Checks if the `callback` returns a truthy value for **all** elements of a
   * `collection`. The `callback` is bound to `thisArg` and invoked with three
   * arguments; (value, index|key, collection).
   *
   * @static
   * @memberOf _
   * @alias all
   * @category Collections
   * @param {Array|Object|String} collection The collection to iterate over.
   * @param {Function} [callback=identity] The function called per iteration.
   * @param {Mixed} [thisArg] The `this` binding for the callback.
   * @returns {Boolean} Returns `true` if all elements pass the callback check,
   *  else `false`.
   * @example
   *
   * _.every([true, 1, null, 'yes'], Boolean);
   * // => false
   */
  var every = createIterator(baseIteratorOptions, everyIteratorOptions);

  /**
   * Examines each element in a `collection`, returning an array of all elements
   * the `callback` returns truthy for. The `callback` is bound to `thisArg` and
   * invoked with three arguments; (value, index|key, collection).
   *
   * @static
   * @memberOf _
   * @alias select
   * @category Collections
   * @param {Array|Object|String} collection The collection to iterate over.
   * @param {Function} [callback=identity] The function called per iteration.
   * @param {Mixed} [thisArg] The `this` binding for the callback.
   * @returns {Array} Returns a new array of elements that passed the callback check.
   * @example
   *
   * var evens = _.filter([1, 2, 3, 4, 5, 6], function(num) { return num % 2 == 0; });
   * // => [2, 4, 6]
   */
  var filter = createIterator(baseIteratorOptions, filterIteratorOptions);

  /**
   * Examines each element in a `collection`, returning the first one the `callback`
   * returns truthy for. The function returns as soon as it finds an acceptable
   * element, and does not iterate over the entire `collection`. The `callback` is
   * bound to `thisArg` and invoked with three arguments; (value, index|key, collection).
   *
   * @static
   * @memberOf _
   * @alias detect
   * @category Collections
   * @param {Array|Object|String} collection The collection to iterate over.
   * @param {Function} callback The function called per iteration.
   * @param {Mixed} [thisArg] The `this` binding for the callback.
   * @returns {Mixed} Returns the element that passed the callback check,
   *  else `undefined`.
   * @example
   *
   * var even = _.find([1, 2, 3, 4, 5, 6], function(num) { return num % 2 == 0; });
   * // => 2
   */
  var find = createIterator(baseIteratorOptions, forEachIteratorOptions, {
    'init': '',
    'inLoop': 'if (callback(value, index, collection)) return value'
  });

  /**
   * Iterates over a `collection`, executing the `callback` for each element in
   * the `collection`. The `callback` is bound to `thisArg` and invoked with three
   * arguments; (value, index|key, collection). Callbacks may exit iteration early
   * by explicitly returning `false`.
   *
   * @static
   * @memberOf _
   * @alias each
   * @category Collections
   * @param {Array|Object|String} collection The collection to iterate over.
   * @param {Function} callback The function called per iteration.
   * @param {Mixed} [thisArg] The `this` binding for the callback.
   * @returns {Array|Object|String} Returns `collection`.
   * @example
   *
   * _([1, 2, 3]).forEach(alert).join(',');
   * // => alerts each number and returns '1,2,3'
   *
   * _.forEach({ 'one': 1, 'two': 2, 'three': 3 }, alert);
   * // => alerts each number (order is not guaranteed)
   */
  var forEach = createIterator(baseIteratorOptions, forEachIteratorOptions);

  /**
   * Creates an object composed of keys returned from running each element of
   * `collection` through a `callback`. The corresponding value of each key is an
   * array of elements passed to `callback` that returned the key. The `callback`
   * is bound to `thisArg` and invoked with three arguments; (value, index|key, collection).
   * The `callback` argument may also be the name of a property to count by (e.g. 'length').
   *
   * @static
   * @memberOf _
   * @category Collections
   * @param {Array|Object|String} collection The collection to iterate over.
   * @param {Function|String} callback|property The function called per iteration
   *  or property name to group by.
   * @param {Mixed} [thisArg] The `this` binding for the callback.
   * @returns {Object} Returns the composed aggregate object.
   * @example
   *
   * _.groupBy([4.2, 6.1, 6.4], function(num) { return Math.floor(num); });
   * // => { '4': [4.2], '6': [6.1, 6.4] }
   *
   * _.groupBy([4.2, 6.1, 6.4], function(num) { return this.floor(num); }, Math);
   * // => { '4': [4.2], '6': [6.1, 6.4] }
   *
   * _.groupBy(['one', 'two', 'three'], 'length');
   * // => { '3': ['one', 'two'], '5': ['three'] }
   */
  var groupBy = createIterator(baseIteratorOptions, countByIteratorOptions, {
    'inLoop':
      'prop = callback(value, index, collection);\n' +
      '(hasOwnProperty.call(result, prop) ? result[prop] : result[prop] = []).push(value)'
  });

  /**
   * Invokes the method named by `methodName` on each element in the `collection`,
   * returning an array of the results of each invoked method. Additional arguments
   * will be passed to each invoked method. If `methodName` is a function it will
   * be invoked for, and `this` bound to, each element in the `collection`.
   *
   * @static
   * @memberOf _
   * @category Collections
   * @param {Array|Object|String} collection The collection to iterate over.
   * @param {Function|String} methodName The name of the method to invoke or
   *  the function invoked per iteration.
   * @param {Mixed} [arg1, arg2, ...] Arguments to invoke the method with.
   * @returns {Array} Returns a new array of the results of each invoked method.
   * @example
   *
   * _.invoke([[5, 1, 7], [3, 2, 1]], 'sort');
   * // => [[1, 5, 7], [1, 2, 3]]
   *
   * _.invoke([123, 456], String.prototype.split, '');
   * // => [['1', '2', '3'], ['4', '5', '6']]
   */
  var invoke = createIterator(mapIteratorOptions, {
    'args': 'collection, methodName',
    'top':
      'var args = slice.call(arguments, 2),\n' +
      '    isFunc = typeof methodName == \'function\'',
    'inLoop': {
      'array':
        'result[index] = (isFunc ? methodName : value[methodName]).apply(value, args)',
      'object':
        'result' + (isKeysFast ? '[ownIndex] = ' : '.push') +
        '((isFunc ? methodName : value[methodName]).apply(value, args))'
    }
  });

  /**
   * Creates an array of values by running each element in the `collection`
   * through a `callback`. The `callback` is bound to `thisArg` and invoked with
   * three arguments; (value, index|key, collection).
   *
   * @static
   * @memberOf _
   * @alias collect
   * @category Collections
   * @param {Array|Object|String} collection The collection to iterate over.
   * @param {Function} [callback=identity] The function called per iteration.
   * @param {Mixed} [thisArg] The `this` binding for the callback.
   * @returns {Array} Returns a new array of the results of each `callback` execution.
   * @example
   *
   * _.map([1, 2, 3], function(num) { return num * 3; });
   * // => [3, 6, 9]
   *
   * _.map({ 'one': 1, 'two': 2, 'three': 3 }, function(num) { return num * 3; });
   * // => [3, 6, 9] (order is not guaranteed)
   */
  var map = createIterator(baseIteratorOptions, mapIteratorOptions);

  /**
   * Retrieves the value of a specified property from all elements in
   * the `collection`.
   *
   * @static
   * @memberOf _
   * @category Collections
   * @param {Array|Object|String} collection The collection to iterate over.
   * @param {String} property The property to pluck.
   * @returns {Array} Returns a new array of property values.
   * @example
   *
   * var stooges = [
   *   { 'name': 'moe', 'age': 40 },
   *   { 'name': 'larry', 'age': 50 },
   *   { 'name': 'curly', 'age': 60 }
   * ];
   *
   * _.pluck(stooges, 'name');
   * // => ['moe', 'larry', 'curly']
   */
  var pluck = createIterator(mapIteratorOptions, {
    'args': 'collection, property',
    'inLoop': {
      'array':  'result[index] = value[property]',
      'object': 'result' + (isKeysFast ? '[ownIndex] = ' : '.push') + '(value[property])'
    }
  });

  /**
   * Boils down a `collection` to a single value. The initial state of the
   * reduction is `accumulator` and each successive step of it should be returned
   * by the `callback`. The `callback` is bound to `thisArg` and invoked with 4
   * arguments; for arrays they are (accumulator, value, index|key, collection).
   *
   * @static
   * @memberOf _
   * @alias foldl, inject
   * @category Collections
   * @param {Array|Object|String} collection The collection to iterate over.
   * @param {Function} callback The function called per iteration.
   * @param {Mixed} [accumulator] Initial value of the accumulator.
   * @param {Mixed} [thisArg] The `this` binding for the callback.
   * @returns {Mixed} Returns the accumulated value.
   * @example
   *
   * var sum = _.reduce([1, 2, 3], function(memo, num) { return memo + num; });
   * // => 6
   */
  var reduce = createIterator({
    'args': 'collection, callback, accumulator, thisArg',
    'init': 'accumulator',
    'top':
      'var noaccum = arguments.length < 3;\n' +
      'if (thisArg) callback = bindIterator(callback, thisArg)',
    'beforeLoop': {
      'array': 'if (noaccum) result = iteratee[++index]'
    },
    'inLoop': {
      'array':
        'result = callback(result, value, index, collection)',
      'object':
        'result = noaccum\n' +
        '  ? (noaccum = false, value)\n' +
        '  : callback(result, value, index, collection)'
    }
  });

  /**
   * The right-associative version of `_.reduce`.
   *
   * @static
   * @memberOf _
   * @alias foldr
   * @category Collections
   * @param {Array|Object|String} collection The collection to iterate over.
   * @param {Function} callback The function called per iteration.
   * @param {Mixed} [accumulator] Initial value of the accumulator.
   * @param {Mixed} [thisArg] The `this` binding for the callback.
   * @returns {Mixed} Returns the accumulated value.
   * @example
   *
   * var list = [[0, 1], [2, 3], [4, 5]];
   * var flat = _.reduceRight(list, function(a, b) { return a.concat(b); }, []);
   * // => [4, 5, 2, 3, 0, 1]
   */
  function reduceRight(collection, callback, accumulator, thisArg) {
    if (!collection) {
      return accumulator;
    }

    var length = collection.length,
        noaccum = arguments.length < 3;

    if(thisArg) {
      callback = bindIterator(callback, thisArg);
    }
    if (length === +length) {
      var iteratee = noCharByIndex && toString.call(collection) == stringClass
        ? collection.split('')
        : collection;

      if (length && noaccum) {
        accumulator = iteratee[--length];
      }
      while (length--) {
        accumulator = callback(accumulator, iteratee[length], length, collection);
      }
      return accumulator;
    }

    var prop,
        props = keys(collection);

    length = props.length;
    if (length && noaccum) {
      accumulator = collection[props[--length]];
    }
    while (length--) {
      prop = props[length];
      accumulator = callback(accumulator, collection[prop], prop, collection);
    }
    return accumulator;
  }

  /**
   * The opposite of `_.filter`, this method returns the values of a
   * `collection` that `callback` does **not** return truthy for.
   *
   * @static
   * @memberOf _
   * @category Collections
   * @param {Array|Object|String} collection The collection to iterate over.
   * @param {Function} [callback=identity] The function called per iteration.
   * @param {Mixed} [thisArg] The `this` binding for the callback.
   * @returns {Array} Returns a new array of elements that did **not** pass the
   *  callback check.
   * @example
   *
   * var odds = _.reject([1, 2, 3, 4, 5, 6], function(num) { return num % 2 == 0; });
   * // => [1, 3, 5]
   */
  var reject = createIterator(baseIteratorOptions, filterIteratorOptions, {
    'inLoop': '!' + filterIteratorOptions.inLoop
  });

  /**
   * Gets the size of the `collection` by returning `collection.length` for arrays
   * and array-like objects or the number of own enumerable properties for objects.
   *
   * @static
   * @memberOf _
   * @category Collections
   * @param {Array|Object|String} collection The collection to inspect.
   * @returns {Number} Returns `collection.length` or number of own enumerable properties.
   * @example
   *
   * _.size([1, 2]);
   * // => 2
   *
   * _.size({ 'one': 1, 'two': 2, 'three': 3 });
   * // => 3
   *
   * _.size('curly');
   * // => 5
   */
  function size(collection) {
    if (!collection) {
      return 0;
    }
    var length = collection.length;
    return length === +length ? length : keys(collection).length;
  }

  /**
   * Checks if the `callback` returns a truthy value for **any** element of a
   * `collection`. The function returns as soon as it finds passing value, and
   * does not iterate over the entire `collection`. The `callback` is bound to
   * `thisArg` and invoked with three arguments; (value, index|key, collection).
   *
   * @static
   * @memberOf _
   * @alias any
   * @category Collections
   * @param {Array|Object|String} collection The collection to iterate over.
   * @param {Function} [callback=identity] The function called per iteration.
   * @param {Mixed} [thisArg] The `this` binding for the callback.
   * @returns {Boolean} Returns `true` if any element passes the callback check,
   *  else `false`.
   * @example
   *
   * _.some([null, 0, 'yes', false]);
   * // => true
   */
  var some = createIterator(baseIteratorOptions, everyIteratorOptions, {
    'init': 'false',
    'inLoop': everyIteratorOptions.inLoop.replace('!', '')
  });

  /**
   * Creates an array, stable sorted in ascending order by the results of
   * running each element of `collection` through a `callback`. The `callback`
   * is bound to `thisArg` and invoked with three arguments; (value, index|key, collection).
   * The `callback` argument may also be the name of a property to sort by (e.g. 'length').
   *
   * @static
   * @memberOf _
   * @category Collections
   * @param {Array|Object|String} collection The collection to iterate over.
   * @param {Function|String} callback|property The function called per iteration
   *  or property name to sort by.
   * @param {Mixed} [thisArg] The `this` binding for the callback.
   * @returns {Array} Returns a new array of sorted elements.
   * @example
   *
   * _.sortBy([1, 2, 3], function(num) { return Math.sin(num); });
   * // => [3, 1, 2]
   *
   * _.sortBy([1, 2, 3], function(num) { return this.sin(num); }, Math);
   * // => [3, 1, 2]
   *
   * _.sortBy(['larry', 'brendan', 'moe'], 'length');
   * // => ['moe', 'larry', 'brendan']
   */
  var sortBy = createIterator(baseIteratorOptions, countByIteratorOptions, mapIteratorOptions, {
    'inLoop': {
      'array':
        'result[index] = {\n' +
        '  criteria: callback(value, index, collection),\n' +
        '  index: index,\n' +
        '  value: value\n' +
        '}',
      'object':
        'result' + (isKeysFast ? '[ownIndex] = ' : '.push') + '({\n' +
        '  criteria: callback(value, index, collection),\n' +
        '  index: index,\n' +
        '  value: value\n' +
        '})'
    },
    'bottom':
      'result.sort(compareAscending);\n' +
      'length = result.length;\n' +
      'while (length--) {\n' +
      '  result[length] = result[length].value\n' +
      '}'
  });

  /**
   * Converts the `collection`, to an array.
   *
   * @static
   * @memberOf _
   * @category Collections
   * @param {Array|Object|String} collection The collection to convert.
   * @returns {Array} Returns the new converted array.
   * @example
   *
   * (function() { return _.toArray(arguments).slice(1); })(1, 2, 3, 4);
   * // => [2, 3, 4]
   */
  function toArray(collection) {
    if (!collection) {
      return [];
    }
    var length = collection.length;
    if (length === +length) {
      return (noArraySliceOnStrings ? toString.call(collection) == stringClass : typeof collection == 'string')
        ? collection.split('')
        : slice.call(collection);
    }
    return values(collection);
  }

  /**
   * Examines each element in a `collection`, returning an array of all elements
   * that contain the given `properties`.
   *
   * @static
   * @memberOf _
   * @category Collections
   * @param {Array|Object|String} collection The collection to iterate over.
   * @param {Object} properties The object of properties/values to filter by.
   * @returns {Array} Returns a new array of elements that contain the given `properties`.
   * @example
   *
   * var stooges = [
   *   { 'name': 'moe', 'age': 40 },
   *   { 'name': 'larry', 'age': 50 },
   *   { 'name': 'curly', 'age': 60 }
   * ];
   *
   * _.where(stooges, { 'age': 40 });
   * // => [{ 'name': 'moe', 'age': 40 }]
   */
  var where = createIterator(filterIteratorOptions, {
    'args': 'collection, properties',
    'top':
      'var props = [];\n' +
      'forIn(properties, function(value, prop) { props.push(prop) });\n' +
      'var propsLength = props.length',
    'inLoop':
      'for (var prop, pass = true, propIndex = 0; propIndex < propsLength; propIndex++) {\n' +
      '  prop = props[propIndex];\n' +
      '  if (!(pass = value[prop] === properties[prop])) break\n' +
      '}\n' +
      'pass && result.push(value)'
  });

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

  /**
   * Creates an array with all falsey values of `array` removed. The values
   * `false`, `null`, `0`, `""`, `undefined` and `NaN` are all falsey.
   *
   * @static
   * @memberOf _
   * @category Arrays
   * @param {Array} array The array to compact.
   * @returns {Array} Returns a new filtered array.
   * @example
   *
   * _.compact([0, 1, false, 2, '', 3]);
   * // => [1, 2, 3]
   */
  function compact(array) {
    var result = [];
    if (!array) {
      return result;
    }
    var index = -1,
        length = array.length;

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

  /**
   * Creates an array of `array` elements not present in the other arrays
   * using strict equality for comparisons, i.e. `===`.
   *
   * @static
   * @memberOf _
   * @category Arrays
   * @param {Array} array The array to process.
   * @param {Array} [array1, array2, ...] Arrays to check.
   * @returns {Array} Returns a new array of `array` elements not present in the
   *  other arrays.
   * @example
   *
   * _.difference([1, 2, 3, 4, 5], [5, 2, 10]);
   * // => [1, 3, 4]
   */
  function difference(array) {
    var result = [];
    if (!array) {
      return result;
    }
    var index = -1,
        length = array.length,
        flattened = concat.apply(result, arguments),
        contains = cachedContains(flattened, length);

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

  /**
   * Gets the first element of the `array`. Pass `n` to return the first `n`
   * elements of the `array`.
   *
   * @static
   * @memberOf _
   * @alias head, take
   * @category Arrays
   * @param {Array} array The array to query.
   * @param {Number} [n] The number of elements to return.
   * @param {Object} [guard] Internally used to allow this method to work with
   *  others like `_.map` without using their callback `index` argument for `n`.
   * @returns {Mixed} Returns the first element or an array of the first `n`
   *  elements of `array`.
   * @example
   *
   * _.first([5, 4, 3, 2, 1]);
   * // => 5
   */
  function first(array, n, guard) {
    if (array) {
      return (n == null || guard) ? array[0] : slice.call(array, 0, n);
    }
  }

  /**
   * Flattens a nested array (the nesting can be to any depth). If `shallow` is
   * truthy, `array` will only be flattened a single level.
   *
   * @static
   * @memberOf _
   * @category Arrays
   * @param {Array} array The array to compact.
   * @param {Boolean} shallow A flag to indicate only flattening a single level.
   * @returns {Array} Returns a new flattened array.
   * @example
   *
   * _.flatten([1, [2], [3, [[4]]]]);
   * // => [1, 2, 3, 4];
   *
   * _.flatten([1, [2], [3, [[4]]]], true);
   * // => [1, 2, 3, [[4]]];
   */
  function flatten(array, shallow) {
    var result = [];
    if (!array) {
      return result;
    }
    var value,
        index = -1,
        length = array.length;

    while (++index < length) {
      value = array[index];

      // recursively flatten arrays (susceptible to call stack limits)
      if (isArray(value)) {
        push.apply(result, shallow ? value : flatten(value));
      } else {
        result.push(value);
      }
    }
    return result;
  }

  /**
   * Gets the index at which the first occurrence of `value` is found using
   * strict equality for comparisons, i.e. `===`. If the `array` is already
   * sorted, passing `true` for `isSorted` will run a faster binary search.
   *
   * @static
   * @memberOf _
   * @category Arrays
   * @param {Array} array The array to search.
   * @param {Mixed} value The value to search for.
   * @param {Boolean|Number} [fromIndex=0] The index to start searching from or
   *  `true` to perform a binary search on a sorted `array`.
   * @returns {Number} Returns the index of the matched value or `-1`.
   * @example
   *
   * _.indexOf([1, 2, 3, 1, 2, 3], 2);
   * // => 1
   *
   * _.indexOf([1, 2, 3, 1, 2, 3], 2, 3);
   * // => 4
   *
   * _.indexOf([1, 1, 2, 2, 3, 3], 2, true);
   * // => 2
   */
  function indexOf(array, value, fromIndex) {
    if (!array) {
      return -1;
    }
    var index = -1,
        length = array.length;

    if (fromIndex) {
      if (typeof fromIndex == 'number') {
        index = (fromIndex < 0 ? nativeMax(0, length + fromIndex) : fromIndex) - 1;
      } else {
        index = sortedIndex(array, value);
        return array[index] === value ? index : -1;
      }
    }
    while (++index < length) {
      if (array[index] === value) {
        return index;
      }
    }
    return -1;
  }

  /**
   * Gets all but the last element of `array`. Pass `n` to exclude the last `n`
   * elements from the result.
   *
   * @static
   * @memberOf _
   * @category Arrays
   * @param {Array} array The array to query.
   * @param {Number} [n] The number of elements to return.
   * @param {Object} [guard] Internally used to allow this method to work with
   *  others like `_.map` without using their callback `index` argument for `n`.
   * @returns {Array} Returns all but the last element or `n` elements of `array`.
   * @example
   *
   * _.initial([3, 2, 1]);
   * // => [3, 2]
   */
  function initial(array, n, guard) {
    if (!array) {
      return [];
    }
    return slice.call(array, 0, -((n == null || guard) ? 1 : n));
  }

  /**
   * Computes the intersection of all the passed-in arrays using strict equality
   * for comparisons, i.e. `===`.
   *
   * @static
   * @memberOf _
   * @category Arrays
   * @param {Array} [array1, array2, ...] Arrays to process.
   * @returns {Array} Returns a new array of unique elements, in order, that are
   *  present in **all** of the arrays.
   * @example
   *
   * _.intersection([1, 2, 3], [101, 2, 1, 10], [2, 1]);
   * // => [1, 2]
   */
  function intersection(array) {
    var result = [];
    if (!array) {
      return result;
    }
    var value,
        argsLength = arguments.length,
        cache = [],
        index = -1,
        length = array.length;

    array: while (++index < length) {
      value = array[index];
      if (indexOf(result, value) < 0) {
        for (var argsIndex = 1; argsIndex < argsLength; argsIndex++) {
          if (!(cache[argsIndex] || (cache[argsIndex] = cachedContains(arguments[argsIndex])))(value)) {
            continue array;
          }
        }
        result.push(value);
      }
    }
    return result;
  }

  /**
   * Gets the last element of the `array`. Pass `n` to return the lasy `n`
   * elementsvof the `array`.
   *
   * @static
   * @memberOf _
   * @category Arrays
   * @param {Array} array The array to query.
   * @param {Number} [n] The number of elements to return.
   * @param {Object} [guard] Internally used to allow this method to work with
   *  others like `_.map` without using their callback `index` argument for `n`.
   * @returns {Mixed} Returns the last element or an array of the last `n`
   *  elements of `array`.
   * @example
   *
   * _.last([3, 2, 1]);
   * // => 1
   */
  function last(array, n, guard) {
    if (array) {
      var length = array.length;
      return (n == null || guard) ? array[length - 1] : slice.call(array, -n || length);
    }
  }

  /**
   * Gets the index at which the last occurrence of `value` is found using
   * strict equality for comparisons, i.e. `===`.
   *
   * @static
   * @memberOf _
   * @category Arrays
   * @param {Array} array The array to search.
   * @param {Mixed} value The value to search for.
   * @param {Number} [fromIndex=array.length-1] The index to start searching from.
   * @returns {Number} Returns the index of the matched value or `-1`.
   * @example
   *
   * _.lastIndexOf([1, 2, 3, 1, 2, 3], 2);
   * // => 4
   *
   * _.lastIndexOf([1, 2, 3, 1, 2, 3], 2, 3);
   * // => 1
   */
  function lastIndexOf(array, value, fromIndex) {
    if (!array) {
      return -1;
    }
    var index = array.length;
    if (fromIndex && typeof fromIndex == 'number') {
      index = (fromIndex < 0 ? nativeMax(0, index + fromIndex) : nativeMin(fromIndex, index - 1)) + 1;
    }
    while (index--) {
      if (array[index] === value) {
        return index;
      }
    }
    return -1;
  }

  /**
   * Retrieves the maximum value of an `array`. If `callback` is passed,
   * it will be executed for each value in the `array` to generate the
   * criterion by which the value is ranked. The `callback` is bound to
   * `thisArg` and invoked with three arguments; (value, index, array).
   *
   * @static
   * @memberOf _
   * @category Arrays
   * @param {Array} array The array to iterate over.
   * @param {Function} [callback] The function called per iteration.
   * @param {Mixed} [thisArg] The `this` binding for the callback.
   * @returns {Mixed} Returns the maximum value.
   * @example
   *
   * var stooges = [
   *   { 'name': 'moe', 'age': 40 },
   *   { 'name': 'larry', 'age': 50 },
   *   { 'name': 'curly', 'age': 60 }
   * ];
   *
   * _.max(stooges, function(stooge) { return stooge.age; });
   * // => { 'name': 'curly', 'age': 60 };
   */
  function max(array, callback, thisArg) {
    var computed = -Infinity,
        result = computed;

    if (!array) {
      return result;
    }
    var current,
        index = -1,
        length = array.length;

    if (!callback) {
      while (++index < length) {
        if (array[index] > result) {
          result = array[index];
        }
      }
      return result;
    }
    if (thisArg) {
      callback = bindIterator(callback, thisArg);
    }
    while (++index < length) {
      current = callback(array[index], index, array);
      if (current > computed) {
        computed = current;
        result = array[index];
      }
    }
    return result;
  }

  /**
   * Retrieves the minimum value of an `array`. If `callback` is passed,
   * it will be executed for each value in the `array` to generate the
   * criterion by which the value is ranked. The `callback` is bound to `thisArg`
   * and invoked with three arguments; (value, index, array).
   *
   * @static
   * @memberOf _
   * @category Arrays
   * @param {Array} array The array to iterate over.
   * @param {Function} [callback] The function called per iteration.
   * @param {Mixed} [thisArg] The `this` binding for the callback.
   * @returns {Mixed} Returns the minimum value.
   * @example
   *
   * _.min([10, 5, 100, 2, 1000]);
   * // => 2
   */
  function min(array, callback, thisArg) {
    var computed = Infinity,
        result = computed;

    if (!array) {
      return result;
    }
    var current,
        index = -1,
        length = array.length;

    if (!callback) {
      while (++index < length) {
        if (array[index] < result) {
          result = array[index];
        }
      }
      return result;
    }
    if (thisArg) {
      callback = bindIterator(callback, thisArg);
    }
    while (++index < length) {
      current = callback(array[index], index, array);
      if (current < computed) {
        computed = current;
        result = array[index];
      }
    }
    return result;
  }

  /**
   * Creates an object composed from arrays of `keys` and `values`. Pass either
   * a single two dimensional array, i.e. `[[key1, value1], [key2, value2]]`, or
   * two arrays, one of `keys` and one of corresponding `values`.
   *
   * @static
   * @memberOf _
   * @category Arrays
   * @param {Array} keys The array of keys.
   * @param {Array} [values=[]] The array of values.
   * @returns {Object} Returns an object composed of the given keys and
   *  corresponding values.
   * @example
   *
   * _.object(['moe', 'larry', 'curly'], [30, 40, 50]);
   * // => { 'moe': 30, 'larry': 40, 'curly': 50 }
   */
  function object(keys, values) {
    if (!keys) {
      return {};
    }
    var index = -1,
        length = keys.length,
        result = {};

    while (++index < length) {
      if (values) {
        result[keys[index]] = values[index];
      } else {
        result[keys[index][0]] = keys[index][1];
      }
    }
    return result;
  }

  /**
   * Creates an array of numbers (positive and/or negative) progressing from
   * `start` up to but not including `stop`. This method is a port of Python's
   * `range()` function. See http://docs.python.org/library/functions.html#range.
   *
   * @static
   * @memberOf _
   * @category Arrays
   * @param {Number} [start=0] The start of the range.
   * @param {Number} end The end of the range.
   * @param {Number} [step=1] The value to increment or descrement by.
   * @returns {Array} Returns a new range array.
   * @example
   *
   * _.range(10);
   * // => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
   *
   * _.range(1, 11);
   * // => [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
   *
   * _.range(0, 30, 5);
   * // => [0, 5, 10, 15, 20, 25]
   *
   * _.range(0, -10, -1);
   * // => [0, -1, -2, -3, -4, -5, -6, -7, -8, -9]
   *
   * _.range(0);
   * // => []
   */
  function range(start, end, step) {
    start = +start || 0;
    step = +step || 1;

    if (end == null) {
      end = start;
      start = 0;
    }
    // use `Array(length)` so V8 will avoid the slower "dictionary" mode
    // http://www.youtube.com/watch?v=XAqIpGU8ZZk#t=16m27s
    var index = -1,
        length = nativeMax(0, Math.ceil((end - start) / step)),
        result = Array(length);

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

  /**
   * The opposite of `_.initial`, this method gets all but the first value of
   * `array`. Pass `n` to exclude the first `n` values from the result.
   *
   * @static
   * @memberOf _
   * @alias drop, tail
   * @category Arrays
   * @param {Array} array The array to query.
   * @param {Number} [n] The number of elements to return.
   * @param {Object} [guard] Internally used to allow this method to work with
   *  others like `_.map` without using their callback `index` argument for `n`.
   * @returns {Array} Returns all but the first value or `n` values of `array`.
   * @example
   *
   * _.rest([3, 2, 1]);
   * // => [2, 1]
   */
  function rest(array, n, guard) {
    if (!array) {
      return [];
    }
    return slice.call(array, (n == null || guard) ? 1 : n);
  }

  /**
   * Creates an array of shuffled `array` values, using a version of the
   * Fisher-Yates shuffle. See http://en.wikipedia.org/wiki/Fisher-Yates_shuffle.
   *
   * @static
   * @memberOf _
   * @category Arrays
   * @param {Array} array The array to shuffle.
   * @returns {Array} Returns a new shuffled array.
   * @example
   *
   * _.shuffle([1, 2, 3, 4, 5, 6]);
   * // => [4, 1, 6, 3, 5, 2]
   */
  function shuffle(array) {
    if (!array) {
      return [];
    }
    var rand,
        index = -1,
        length = array.length,
        result = Array(length);

    while (++index < length) {
      rand = nativeFloor(nativeRandom() * (index + 1));
      result[index] = result[rand];
      result[rand] = array[index];
    }
    return result;
  }

  /**
   * Uses a binary search to determine the smallest index at which the `value`
   * should be inserted into `array` in order to maintain the sort order of the
   * sorted `array`. If `callback` is passed, it will be executed for `value` and
   * each element in `array` to compute their sort ranking. The `callback` is
   * bound to `thisArg` and invoked with one argument; (value).
   *
   * @static
   * @memberOf _
   * @category Arrays
   * @param {Array} array The array to iterate over.
   * @param {Mixed} value The value to evaluate.
   * @param {Function} [callback=identity] The function called per iteration.
   * @param {Mixed} [thisArg] The `this` binding for the callback.
   * @returns {Number} Returns the index at which the value should be inserted
   *  into `array`.
   * @example
   *
   * _.sortedIndex([20, 30, 40], 35);
   * // => 2
   *
   * var dict = {
   *   'wordToNumber': { 'twenty': 20, 'thirty': 30, 'thirty-five': 35, 'fourty': 40 }
   * };
   *
   * _.sortedIndex(['twenty', 'thirty', 'fourty'], 'thirty-five', function(word) {
   *   return dict.wordToNumber[word];
   * });
   * // => 2
   *
   * _.sortedIndex(['twenty', 'thirty', 'fourty'], 'thirty-five', function(word) {
   *   return this.wordToNumber[word];
   * }, dict);
   * // => 2
   */
  function sortedIndex(array, value, callback, thisArg) {
    if (!array) {
      return 0;
    }
    var mid,
        low = 0,
        high = array.length;

    if (callback) {
      if (thisArg) {
        callback = bind(callback, thisArg);
      }
      value = callback(value);
      while (low < high) {
        mid = (low + high) >>> 1;
        callback(array[mid]) < value ? low = mid + 1 : high = mid;
      }
    } else {
      while (low < high) {
        mid = (low + high) >>> 1;
        array[mid] < value ? low = mid + 1 : high = mid;
      }
    }
    return low;
  }

  /**
   * Computes the union of the passed-in arrays using strict equality for
   * comparisons, i.e. `===`.
   *
   * @static
   * @memberOf _
   * @category Arrays
   * @param {Array} [array1, array2, ...] Arrays to process.
   * @returns {Array} Returns a new array of unique values, in order, that are
   *  present in one or more of the arrays.
   * @example
   *
   * _.union([1, 2, 3], [101, 2, 1, 10], [2, 1]);
   * // => [1, 2, 3, 101, 10]
   */
  function union() {
    var index = -1,
        result = [],
        flattened = concat.apply(result, arguments),
        length = flattened.length;

    while (++index < length) {
      if (indexOf(result, flattened[index]) < 0) {
        result.push(flattened[index]);
      }
    }
    return result;
  }

  /**
   * Creates a duplicate-value-free version of the `array` using strict equality
   * for comparisons, i.e. `===`. If the `array` is already sorted, passing `true`
   * for `isSorted` will run a faster algorithm. If `callback` is passed, each
   * element of `array` is passed through a callback` before uniqueness is computed.
   * The `callback` is bound to `thisArg` and invoked with three arguments; (value, index, array).
   *
   * @static
   * @memberOf _
   * @alias unique
   * @category Arrays
   * @param {Array} array The array to process.
   * @param {Boolean} [isSorted=false] A flag to indicate that the `array` is already sorted.
   * @param {Function} [callback=identity] The function called per iteration.
   * @param {Mixed} [thisArg] The `this` binding for the callback.
   * @returns {Array} Returns a duplicate-value-free array.
   * @example
   *
   * _.uniq([1, 2, 1, 3, 1]);
   * // => [1, 2, 3]
   *
   * _.uniq([1, 1, 2, 2, 3], true);
   * // => [1, 2, 3]
   *
   * _.uniq([1, 2, 1.5, 3, 2.5], function(num) { return Math.floor(num); });
   * // => [1, 2, 3]
   *
   * _.uniq([1, 2, 1.5, 3, 2.5], function(num) { return this.floor(num); }, Math);
   * // => [1, 2, 3]
   */
  function uniq(array, isSorted, callback, thisArg) {
    var result = [];
    if (!array) {
      return result;
    }
    var computed,
        index = -1,
        length = array.length,
        seen = [];

    // juggle arguments
    if (typeof isSorted == 'function') {
      thisArg = callback;
      callback = isSorted;
      isSorted = false;
    }
    if (!callback) {
      callback = identity;
    } else if (thisArg) {
      callback = bindIterator(callback, thisArg);
    }
    while (++index < length) {
      computed = callback(array[index], index, array);
      if (isSorted
            ? !index || seen[seen.length - 1] !== computed
            : indexOf(seen, computed) < 0
          ) {
        seen.push(computed);
        result.push(array[index]);
      }
    }
    return result;
  }

  /**
   * Creates an array with all occurrences of the passed values removed using
   * strict equality for comparisons, i.e. `===`.
   *
   * @static
   * @memberOf _
   * @category Arrays
   * @param {Array} array The array to filter.
   * @param {Mixed} [value1, value2, ...] Values to remove.
   * @returns {Array} Returns a new filtered array.
   * @example
   *
   * _.without([1, 2, 1, 0, 3, 1, 4], 0, 1);
   * // => [2, 3, 4]
   */
  function without(array) {
    var result = [];
    if (!array) {
      return result;
    }
    var index = -1,
        length = array.length,
        contains = cachedContains(arguments, 1, 20);

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

  /**
   * Groups the elements of each array at their corresponding indexes. Useful for
   * separate data sources that are coordinated through matching array indexes.
   * For a matrix of nested arrays, `_.zip.apply(...)` can transpose the matrix
   * in a similar fashion.
   *
   * @static
   * @memberOf _
   * @category Arrays
   * @param {Array} [array1, array2, ...] Arrays to process.
   * @returns {Array} Returns a new array of grouped elements.
   * @example
   *
   * _.zip(['moe', 'larry', 'curly'], [30, 40, 50], [true, false, false]);
   * // => [['moe', 30, true], ['larry', 40, false], ['curly', 50, false]]
   */
  function zip(array) {
    if (!array) {
      return [];
    }
    var index = -1,
        length = max(pluck(arguments, 'length')),
        result = Array(length);

    while (++index < length) {
      result[index] = pluck(arguments, index);
    }
    return result;
  }

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

  /**
   * Creates a function that is restricted to executing only after it is
   * called `n` times.
   *
   * @static
   * @memberOf _
   * @category Functions
   * @param {Number} n The number of times the function must be called before
   * it is executed.
   * @param {Function} func The function to restrict.
   * @returns {Function} Returns the new restricted function.
   * @example
   *
   * var renderNotes = _.after(notes.length, render);
   * _.forEach(notes, function(note) {
   *   note.asyncSave({ 'success': renderNotes });
   * });
   * // `renderNotes` is run once, after all notes have saved
   */
  function after(n, func) {
    if (n < 1) {
      return func();
    }
    return function() {
      if (--n < 1) {
        return func.apply(this, arguments);
      }
    };
  }

  /**
   * Creates a function that, when called, invokes `func` with the `this`
   * binding of `thisArg` and prepends any additional `bind` arguments to those
   * passed to the bound function.
   *
   * @static
   * @memberOf _
   * @category Functions
   * @param {Function} func The function to bind.
   * @param {Mixed} [thisArg] The `this` binding of `func`.
   * @param {Mixed} [arg1, arg2, ...] Arguments to be partially applied.
   * @returns {Function} Returns the new bound function.
   * @example
   *
   * var func = function(greeting) {
   *   return greeting + ' ' + this.name;
   * };
   *
   * func = _.bind(func, { 'name': 'moe' }, 'hi');
   * func();
   * // => 'hi moe'
   */
  function bind(func, thisArg) {
    // use `Function#bind` if it exists and is fast
    // (in V8 `Function#bind` is slower except when partially applied)
    return isBindFast || (nativeBind && arguments.length > 2)
      ? nativeBind.call.apply(nativeBind, arguments)
      : createBound(func, thisArg, slice.call(arguments, 2));
  }

  /**
   * Binds methods on `object` to `object`, overwriting the existing method.
   * If no method names are provided, all the function properties of `object`
   * will be bound.
   *
   * @static
   * @memberOf _
   * @category Functions
   * @param {Object} object The object to bind and assign the bound methods to.
   * @param {String} [methodName1, methodName2, ...] Method names on the object to bind.
   * @returns {Object} Returns `object`.
   * @example
   *
   * var buttonView = {
   *  'label': 'lodash',
   *  'onClick': function() { alert('clicked: ' + this.label); }
   * };
   *
   * _.bindAll(buttonView);
   * jQuery('#lodash_button').on('click', buttonView.onClick);
   * // => When the button is clicked, `this.label` will have the correct value
   */
  var bindAll = createIterator({
    'useHas': false,
    'useStrict': false,
    'args': 'object',
    'init': 'object',
    'top':
      'var funcs = arguments,\n' +
      '    length = funcs.length;\n' +
      'if (length > 1) {\n' +
      '  for (var index = 1; index < length; index++) {\n' +
      '    result[funcs[index]] = bind(result[funcs[index]], result)\n' +
      '  }\n' +
      '  return result\n' +
      '}',
    'inLoop':
      'if (isFunction(result[index])) {\n' +
      '  result[index] = bind(result[index], result)\n' +
      '}'
  });

  /**
   * Creates a function that is the composition of the passed functions,
   * where each function consumes the return value of the function that follows.
   * In math terms, composing the functions `f()`, `g()`, and `h()` produces `f(g(h()))`.
   *
   * @static
   * @memberOf _
   * @category Functions
   * @param {Function} [func1, func2, ...] Functions to compose.
   * @returns {Function} Returns the new composed function.
   * @example
   *
   * var greet = function(name) { return 'hi: ' + name; };
   * var exclaim = function(statement) { return statement + '!'; };
   * var welcome = _.compose(exclaim, greet);
   * welcome('moe');
   * // => 'hi: moe!'
   */
  function compose() {
    var funcs = arguments;
    return function() {
      var args = arguments,
          length = funcs.length;

      while (length--) {
        args = [funcs[length].apply(this, args)];
      }
      return args[0];
    };
  }

  /**
   * Creates a function that will delay the execution of `func` until after
   * `wait` milliseconds have elapsed since the last time it was invoked. Pass
   * `true` for `immediate` to cause debounce to invoke `func` on the leading,
   * instead of the trailing, edge of the `wait` timeout. Subsequent calls to
   * the debounced function will return the result of the last `func` call.
   *
   * @static
   * @memberOf _
   * @category Functions
   * @param {Function} func The function to debounce.
   * @param {Number} wait The number of milliseconds to delay.
   * @param {Boolean} immediate A flag to indicate execution is on the leading
   *  edge of the timeout.
   * @returns {Function} Returns the new debounced function.
   * @example
   *
   * var lazyLayout = _.debounce(calculateLayout, 300);
   * jQuery(window).on('resize', lazyLayout);
   */
  function debounce(func, wait, immediate) {
    var args,
        result,
        thisArg,
        timeoutId;

    function delayed() {
      timeoutId = null;
      if (!immediate) {
        result = func.apply(thisArg, args);
      }
    }

    return function() {
      var isImmediate = immediate && !timeoutId;
      args = arguments;
      thisArg = this;

      clearTimeout(timeoutId);
      timeoutId = setTimeout(delayed, wait);

      if (isImmediate) {
        result = func.apply(thisArg, args);
      }
      return result;
    };
  }

  /**
   * Executes the `func` function after `wait` milliseconds. Additional arguments
   * will be passed to `func` when it is invoked.
   *
   * @static
   * @memberOf _
   * @category Functions
   * @param {Function} func The function to delay.
   * @param {Number} wait The number of milliseconds to delay execution.
   * @param {Mixed} [arg1, arg2, ...] Arguments to invoke the function with.
   * @returns {Number} Returns the `setTimeout` timeout id.
   * @example
   *
   * var log = _.bind(console.log, console);
   * _.delay(log, 1000, 'logged later');
   * // => 'logged later' (Appears after one second.)
   */
  function delay(func, wait) {
    var args = slice.call(arguments, 2);
    return setTimeout(function() { return func.apply(undefined, args); }, wait);
  }

  /**
   * Defers executing the `func` function until the current call stack has cleared.
   * Additional arguments will be passed to `func` when it is invoked.
   *
   * @static
   * @memberOf _
   * @category Functions
   * @param {Function} func The function to defer.
   * @param {Mixed} [arg1, arg2, ...] Arguments to invoke the function with.
   * @returns {Number} Returns the `setTimeout` timeout id.
   * @example
   *
   * _.defer(function() { alert('deferred'); });
   * // returns from the function before `alert` is called
   */
  function defer(func) {
    var args = slice.call(arguments, 1);
    return setTimeout(function() { return func.apply(undefined, args); }, 1);
  }

  /**
   * Creates a function that, when called, invokes `object[methodName]` and
   * prepends any additional `lateBind` arguments to those passed to the bound
   * function. This method
   *
   * @static
   * @memberOf _
   * @category Functions
   * @param {Object} object The object the method belongs to.
   * @param {String} methodName The method name.
   * @param {Mixed} [arg1, arg2, ...] Arguments to be partially applied.
   * @returns {Function} Returns the new bound function.
   * @example
   *
   * var object = {
   *   'name': 'moe',
   *   'greet': function(greeting) {
   *     return greeting + ' ' + this.name;
   *   }
   * };
   *
   * var func = _.bind(object, 'greet', 'hi');
   * func();
   * // => 'hi moe'
   *
   * object.greet = function(greeting) {
   *   return greeting + ', ' + this.name + '!';
   * };
   *
   * func();
   * // => 'hi, moe!'
   */
  function lateBind(object, methodName) {
    return createBound(methodName, object, slice.call(arguments, 2));
  }

  /**
   * Creates a function that memoizes the result of `func`. If `resolver` is
   * passed, it will be used to determine the cache key for storing the result
   * based on the arguments passed to the memoized function. By default, the first
   * argument passed to the memoized function is used as the cache key.
   *
   * @static
   * @memberOf _
   * @category Functions
   * @param {Function} func The function to have its output memoized.
   * @param {Function} [resolver] A function used to resolve the cache key.
   * @returns {Function} Returns the new memoizing function.
   * @example
   *
   * var fibonacci = _.memoize(function(n) {
   *   return n < 2 ? n : fibonacci(n - 1) + fibonacci(n - 2);
   * });
   */
  function memoize(func, resolver) {
    var cache = {};
    return function() {
      var prop = resolver ? resolver.apply(this, arguments) : arguments[0];
      return hasOwnProperty.call(cache, prop)
        ? cache[prop]
        : (cache[prop] = func.apply(this, arguments));
    };
  }

  /**
   * Creates a function that is restricted to one execution. Repeat calls to
   * the function will return the value of the first call.
   *
   * @static
   * @memberOf _
   * @category Functions
   * @param {Function} func The function to restrict.
   * @returns {Function} Returns the new restricted function.
   * @example
   *
   * var initialize = _.once(createApplication);
   * initialize();
   * initialize();
   * // Application is only created once.
   */
  function once(func) {
    var result,
        ran = false;

    return function() {
      if (ran) {
        return result;
      }
      ran = true;
      result = func.apply(this, arguments);

      // clear the `func` variable so the function may be garbage collected
      func = null;
      return result;
    };
  }

  /**
   * Creates a function that, when called, invokes `func` with any additional
   * `partial` arguments prepended to those passed to the new function. This method
   * is similar to `bind`, except it does **not** alter the `this` binding.
   *
   * @static
   * @memberOf _
   * @category Functions
   * @param {Function} func The function to partially apply arguments to.
   * @param {Mixed} [arg1, arg2, ...] Arguments to be partially applied.
   * @returns {Function} Returns the new partially applied function.
   * @example
   *
   * var greet = function(greeting, name) { return greeting + ': ' + name; };
   * var hi = _.partial(greet, 'hi');
   * hi('moe');
   * // => 'hi: moe'
   */
  function partial(func) {
    return createBound(func, slice.call(arguments, 1));
  }

  /**
   * Creates a function that, when executed, will only call the `func`
   * function at most once per every `wait` milliseconds. If the throttled
   * function is invoked more than once during the `wait` timeout, `func` will
   * also be called on the trailing edge of the timeout. Subsequent calls to the
   * throttled function will return the result of the last `func` call.
   *
   * @static
   * @memberOf _
   * @category Functions
   * @param {Function} func The function to throttle.
   * @param {Number} wait The number of milliseconds to throttle executions to.
   * @returns {Function} Returns the new throttled function.
   * @example
   *
   * var throttled = _.throttle(updatePosition, 100);
   * jQuery(window).on('scroll', throttled);
   */
  function throttle(func, wait) {
    var args,
        result,
        thisArg,
        timeoutId,
        lastCalled = 0;

    function trailingCall() {
      lastCalled = new Date;
      timeoutId = null;
      result = func.apply(thisArg, args);
    }

    return function() {
      var now = new Date,
          remain = wait - (now - lastCalled);

      args = arguments;
      thisArg = this;

      if (remain <= 0) {
        lastCalled = now;
        result = func.apply(thisArg, args);
      }
      else if (!timeoutId) {
        timeoutId = setTimeout(trailingCall, remain);
      }
      return result;
    };
  }

  /**
   * Creates a function that passes `value` to the `wrapper` function as its
   * first argument. Additional arguments passed to the new function are appended
   * to those passed to the `wrapper` function.
   *
   * @static
   * @memberOf _
   * @category Functions
   * @param {Mixed} value The value to wrap.
   * @param {Function} wrapper The wrapper function.
   * @returns {Function} Returns the new function.
   * @example
   *
   * var hello = function(name) { return 'hello: ' + name; };
   * hello = _.wrap(hello, function(func) {
   *   return 'before, ' + func('moe') + ', after';
   * });
   * hello();
   * // => 'before, hello: moe, after'
   */
  function wrap(value, wrapper) {
    return function() {
      var args = [value];
      if (arguments.length) {
        push.apply(args, arguments);
      }
      return wrapper.apply(this, args);
    };
  }

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

  /**
   * Converts the characters `&`, `<`, `>`, `"`, and `'` in `string` to their
   * corresponding HTML entities.
   *
   * @static
   * @memberOf _
   * @category Utilities
   * @param {String} string The string to escape.
   * @returns {String} Returns the escaped string.
   * @example
   *
   * _.escape('Moe, Larry & Curly');
   * // => "Moe, Larry &amp; Curly"
   */
  function escape(string) {
    return string == null ? '' : (string + '').replace(reUnescapedHtml, escapeHtmlChar);
  }

  /**
   * This function returns the first argument passed to it.
   *
   * Note: It is used throughout Lo-Dash as a default callback.
   *
   * @static
   * @memberOf _
   * @category Utilities
   * @param {Mixed} value Any value.
   * @returns {Mixed} Returns `value`.
   * @example
   *
   * var moe = { 'name': 'moe' };
   * moe === _.identity(moe);
   * // => true
   */
  function identity(value) {
    return value;
  }

  /**
   * Adds functions properties of `object` to the `lodash` function and chainable
   * wrapper.
   *
   * @static
   * @memberOf _
   * @category Utilities
   * @param {Object} object The object of function properties to add to `lodash`.
   * @example
   *
   * _.mixin({
   *   'capitalize': function(string) {
   *     return string.charAt(0).toUpperCase() + string.slice(1).toLowerCase();
   *   }
   * });
   *
   * _.capitalize('larry');
   * // => 'Larry'
   *
   * _('curly').capitalize();
   * // => 'Curly'
   */
  function mixin(object) {
    forEach(functions(object), function(methodName) {
      var func = lodash[methodName] = object[methodName];

      LoDash.prototype[methodName] = function() {
        var args = [this.__wrapped__];
        if (arguments.length) {
          push.apply(args, arguments);
        }
        var result = func.apply(lodash, args);
        if (this.__chain__) {
          result = new LoDash(result);
          result.__chain__ = true;
        }
        return result;
      };
    });
  }

  /**
   * Reverts the '_' variable to its previous value and returns a reference to
   * the `lodash` function.
   *
   * @static
   * @memberOf _
   * @category Utilities
   * @returns {Function} Returns the `lodash` function.
   * @example
   *
   * var lodash = _.noConflict();
   */
  function noConflict() {
    window._ = oldDash;
    return this;
  }

  /**
   * Produces a random number between `min` and `max` (inclusive). If only one
   * argument is passed, a number between `0` and the given number will be returned.
   *
   * @static
   * @memberOf _
   * @category Utilities
   * @param {Number} [min=0] The minimum possible value.
   * @param {Number} [max=1] The maximum possible value.
   * @returns {Number} Returns a random number.
   * @example
   *
   * _.random(0, 5);
   * // => a number between 1 and 5
   *
   * _.random(5);
   * // => also a number between 1 and 5
   */
  function random(min, max) {
    if (min == null && max == null) {
      max = 1;
    }
    min = +min || 0;
    if (max == null) {
      max = min;
      min = 0;
    }
    return min + nativeFloor(nativeRandom() * ((+max || 0) - min + 1));
  }

  /**
   * Resolves the value of `property` on `object`. If `property` is a function
   * it will be invoked and its result returned, else the property value is
   * returned. If `object` is falsey, then `null` is returned.
   *
   * @deprecated
   * @static
   * @memberOf _
   * @category Utilities
   * @param {Object} object The object to inspect.
   * @param {String} property The property to get the result of.
   * @returns {Mixed} Returns the resolved value.
   * @example
   *
   * var object = {
   *   'cheese': 'crumpets',
   *   'stuff': function() {
   *     return 'nonsense';
   *   }
   * };
   *
   * _.result(object, 'cheese');
   * // => 'crumpets'
   *
   * _.result(object, 'stuff');
   * // => 'nonsense'
   */
  function result(object, property) {
    // based on Backbone's private `getValue` function
    // https://github.com/documentcloud/backbone/blob/0.9.2/backbone.js#L1419-1424
    if (!object) {
      return null;
    }
    var value = object[property];
    return isFunction(value) ? object[property]() : value;
  }

  /**
   * A micro-templating method that handles arbitrary delimiters, preserves
   * whitespace, and correctly escapes quotes within interpolated code.
   *
   * Note: In the development build `_.template` utilizes sourceURLs for easier
   * debugging. See http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/#toc-sourceurl
   *
   * Note: Lo-Dash may be used in Chrome extensions by either creating a `lodash csp`
   * build and avoiding `_.template` use, or loading Lo-Dash in a sandboxed page.
   * See http://developer.chrome.com/trunk/extensions/sandboxingEval.html
   *
   * @static
   * @memberOf _
   * @category Utilities
   * @param {String} text The template text.
   * @param {Obect} data The data object used to populate the text.
   * @param {Object} options The options object.
   * @returns {Function|String} Returns a compiled function when no `data` object
   *  is given, else it returns the interpolated text.
   * @example
   *
   * // using a compiled template
   * var compiled = _.template('hello: <%= name %>');
   * compiled({ 'name': 'moe' });
   * // => 'hello: moe'
   *
   * var list = '<% _.forEach(people, function(name) { %> <li><%= name %></li> <% }); %>';
   * _.template(list, { 'people': ['moe', 'larry', 'curly'] });
   * // => '<li>moe</li><li>larry</li><li>curly</li>'
   *
   * // using the "escape" delimiter to escape HTML in data property values
   * _.template('<b><%- value %></b>', { 'value': '<script>' });
   * // => '<b>&lt;script></b>'
   *
   * // using the internal `print` function in "evaluate" delimiters
   * _.template('<% print("Hello " + epithet); %>', { 'epithet': 'stooge' });
   * // => 'Hello stooge.'
   *
   * // using custom template delimiter settings
   * _.templateSettings = {
   *   'interpolate': /\{\{(.+?)\}\}/g
   * };
   *
   * _.template('Hello {{ name }}!', { 'name': 'Mustache' });
   * // => 'Hello Mustache!'
   *
   * // using the `variable` option to ensure a with-statement isn't used in the compiled template
   * var compiled = _.template('hello: <%= data.name %>', null, { 'variable': 'data' });
   * compiled.source;
   * // => function(data) {
   *   var __t, __p = '', __e = _.escape;
   *   __p += 'hello: ' + ((__t = ( data.name )) == null ? '' : __t);
   *   return __p;
   * }
   *
   * // using the `source` property to inline compiled templates for meaningful
   * // line numbers in error messages and a stack trace
   * fs.writeFileSync(path.join(cwd, 'jst.js'), '\
   *   var JST = {\
   *     "main": ' + _.template(mainText).source + '\
   *   };\
   * ');
   */
  function template(text, data, options) {
    // based on John Resig's `tmpl` implementation
    // http://ejohn.org/blog/javascript-micro-templating/
    // and Laura Doktorova's doT.js
    // https://github.com/olado/doT
    options || (options = {});
    text += '';

    var isEvaluating,
        result,
        index = 0,
        settings = lodash.templateSettings,
        source = "__p += '",
        variable = options.variable || settings.variable,
        hasVariable = variable;

    // compile regexp to match each delimiter
    var reDelimiters = RegExp(
      (options.escape || settings.escape || reNoMatch).source + '|' +
      (options.interpolate || settings.interpolate || reNoMatch).source + '|' +
      (options.evaluate || settings.evaluate || reNoMatch).source + '|$'
    , 'g');

    text.replace(reDelimiters, function(match, escapeValue, interpolateValue, evaluateValue, offset) {
      // escape characters that cannot be included in string literals
      source += text.slice(index, offset).replace(reUnescapedString, escapeStringChar);

      // replace delimiters with snippets
      source +=
        escapeValue ? "' +\n__e(" + escapeValue + ") +\n'" :
        evaluateValue ? "';\n" + evaluateValue + ";\n__p += '" :
        interpolateValue ? "' +\n((__t = (" + interpolateValue + ")) == null ? '' : __t) +\n'" : '';

      isEvaluating || (isEvaluating = evaluateValue || reComplexDelimiter.test(escapeValue || interpolateValue));
      index = offset + match.length;
    });

    source += "';\n";

    // if `variable` is not specified and the template contains "evaluate"
    // delimiters, wrap a with-statement around the generated code to add the
    // data object to the top of the scope chain
    if (!hasVariable) {
      variable = 'obj';
      if (isEvaluating) {
        source = 'with (' + variable + ') {\n' + source + '\n}\n';
      }
      else {
        // avoid a with-statement by prepending data object references to property names
        var reDoubleVariable = RegExp('(\\(\\s*)' + variable + '\\.' + variable + '\\b', 'g');
        source = source
          .replace(reInsertVariable, '$&' + variable + '.')
          .replace(reDoubleVariable, '$1__d');
      }
    }

    // cleanup code by stripping empty strings
    source = (isEvaluating ? source.replace(reEmptyStringLeading, '') : source)
      .replace(reEmptyStringMiddle, '$1')
      .replace(reEmptyStringTrailing, '$1;');

    // frame code as the function body
    source = 'function(' + variable + ') {\n' +
      (hasVariable ? '' : variable + ' || (' + variable + ' = {});\n') +
      'var __t, __p = \'\', __e = _.escape' +
      (isEvaluating
        ? ', __j = Array.prototype.join;\n' +
          'function print() { __p += __j.call(arguments, \'\') }\n'
        : (hasVariable ? '' : ', __d = ' + variable + '.' + variable + ' || ' + variable) + ';\n'
      ) +
      source +
      'return __p\n}';

    // use a sourceURL for easier debugging
    // http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/#toc-sourceurl
    var sourceURL = useSourceURL
      ? '\n//@ sourceURL=/lodash/template/source[' + (templateCounter++) + ']'
      : '';

    try {
      result = Function('_', 'return ' + source + sourceURL)(lodash);
    } catch(e) {
      e.source = source;
      throw e;
    }

    if (data) {
      return result(data);
    }
    // provide the compiled function's source via its `toString` method, in
    // supported environments, or the `source` property as a convenience for
    // inlining compiled templates during the build process
    result.source = source;
    return result;
  }

  /**
   * Executes the `callback` function `n` times, returning an array of the results
   * of each `callback` execution. The `callback` is bound to `thisArg` and invoked
   * with one argument; (index).
   *
   * @static
   * @memberOf _
   * @category Utilities
   * @param {Number} n The number of times to execute the callback.
   * @param {Function} callback The function called per iteration.
   * @param {Mixed} [thisArg] The `this` binding for the callback.
   * @returns {Array} Returns a new array of the results of each `callback` execution.
   * @example
   *
   * var diceRolls = _.times(3, _.partial(_.random, 1, 6));
   * // => [3, 6, 4]
   *
   * _.times(3, function(n) { mage.castSpell(n); });
   * // => calls `mage.castSpell(n)` three times, passing `n` of `0`, `1`, and `2` respectively
   *
   * _.times(3, function(n) { this.cast(n); }, mage);
   * // => also calls `mage.castSpell(n)` three times
   */
  function times(n, callback, thisArg) {
    var index = -1,
        result = Array(n || 0);

    if (thisArg) {
      while (++index < n) {
        result[index] = callback.call(thisArg, index);
      }
    } else {
      while (++index < n) {
        result[index] = callback(index);
      }
    }
    return result;
  }

  /**
   * Converts the HTML entities `&amp;`, `&lt;`, `&gt;`, `&quot;`, and `&#x27;`
   * in `string` to their corresponding characters.
   *
   * @static
   * @memberOf _
   * @category Utilities
   * @param {String} string The string to unescape.
   * @returns {String} Returns the unescaped string.
   * @example
   *
   * _.unescape('Moe, Larry &amp; Curly');
   * // => "Moe, Larry & Curly"
   */
  function unescape(string) {
    return string == null ? '' : (string + '').replace(reEscapedHtml, unescapeHtmlChar);
  }

  /**
   * Generates a unique id. If `prefix` is passed, the id will be appended to it.
   *
   * @static
   * @memberOf _
   * @category Utilities
   * @param {String} [prefix] The value to prefix the id with.
   * @returns {Number|String} Returns a numeric id if no prefix is passed, else
   *  a string id may be returned.
   * @example
   *
   * _.uniqueId('contact_');
   * // => 'contact_104'
   */
  function uniqueId(prefix) {
    var id = idCounter++;
    return prefix ? prefix + id : id;
  }

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

  /**
   * Wraps the value in a `lodash` wrapper object.
   *
   * @static
   * @memberOf _
   * @category Chaining
   * @param {Mixed} value The value to wrap.
   * @returns {Object} Returns the wrapper object.
   * @example
   *
   * var stooges = [
   *   { 'name': 'moe', 'age': 40 },
   *   { 'name': 'larry', 'age': 50 },
   *   { 'name': 'curly', 'age': 60 }
   * ];
   *
   * var youngest = _.chain(stooges)
   *     .sortBy(function(stooge) { return stooge.age; })
   *     .map(function(stooge) { return stooge.name + ' is ' + stooge.age; })
   *     .first()
   *     .value();
   * // => 'moe is 40'
   */
  function chain(value) {
    value = new LoDash(value);
    value.__chain__ = true;
    return value;
  }

  /**
   * Invokes `interceptor` with the `value` as the first argument, and then
   * returns `value`. The purpose of this method is to "tap into" a method chain,
   * in order to perform operations on intermediate results within the chain.
   *
   * @static
   * @memberOf _
   * @category Chaining
   * @param {Mixed} value The value to pass to `interceptor`.
   * @param {Function} interceptor The function to invoke.
   * @returns {Mixed} Returns `value`.
   * @example
   *
   * _.chain([1, 2, 3, 200])
   *  .filter(function(num) { return num % 2 == 0; })
   *  .tap(alert)
   *  .map(function(num) { return num * num })
   *  .value();
   * // => // [2, 200] (alerted)
   * // => [4, 40000]
   */
  function tap(value, interceptor) {
    interceptor(value);
    return value;
  }

  /**
   * Enables method chaining on the wrapper object.
   *
   * @name chain
   * @deprecated
   * @memberOf _
   * @category Chaining
   * @returns {Mixed} Returns the wrapper object.
   * @example
   *
   * _([1, 2, 3]).value();
   * // => [1, 2, 3]
   */
  function wrapperChain() {
    this.__chain__ = true;
    return this;
  }

  /**
   * Extracts the wrapped value.
   *
   * @name value
   * @memberOf _
   * @category Chaining
   * @returns {Mixed} Returns the wrapped value.
   * @example
   *
   * _([1, 2, 3]).value();
   * // => [1, 2, 3]
   */
  function wrapperValue() {
    return this.__wrapped__;
  }

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

  /**
   * The semantic version number.
   *
   * @static
   * @memberOf _
   * @type String
   */
  lodash.VERSION = '0.7.0';

  // assign static methods
  lodash.after = after;
  lodash.bind = bind;
  lodash.bindAll = bindAll;
  lodash.chain = chain;
  lodash.clone = clone;
  lodash.compact = compact;
  lodash.compose = compose;
  lodash.contains = contains;
  lodash.countBy = countBy;
  lodash.debounce = debounce;
  lodash.defaults = defaults;
  lodash.defer = defer;
  lodash.delay = delay;
  lodash.difference = difference;
  lodash.escape = escape;
  lodash.every = every;
  lodash.extend = extend;
  lodash.filter = filter;
  lodash.find = find;
  lodash.first = first;
  lodash.flatten = flatten;
  lodash.forEach = forEach;
  lodash.forIn = forIn;
  lodash.forOwn = forOwn;
  lodash.functions = functions;
  lodash.groupBy = groupBy;
  lodash.has = has;
  lodash.identity = identity;
  lodash.indexOf = indexOf;
  lodash.initial = initial;
  lodash.intersection = intersection;
  lodash.invert = invert;
  lodash.invoke = invoke;
  lodash.isArguments = isArguments;
  lodash.isArray = isArray;
  lodash.isBoolean = isBoolean;
  lodash.isDate = isDate;
  lodash.isElement = isElement;
  lodash.isEmpty = isEmpty;
  lodash.isEqual = isEqual;
  lodash.isFinite = isFinite;
  lodash.isFunction = isFunction;
  lodash.isNaN = isNaN;
  lodash.isNull = isNull;
  lodash.isNumber = isNumber;
  lodash.isObject = isObject;
  lodash.isRegExp = isRegExp;
  lodash.isString = isString;
  lodash.isUndefined = isUndefined;
  lodash.keys = keys;
  lodash.last = last;
  lodash.lastIndexOf = lastIndexOf;
  lodash.lateBind = lateBind;
  lodash.map = map;
  lodash.max = max;
  lodash.memoize = memoize;
  lodash.merge = merge;
  lodash.min = min;
  lodash.mixin = mixin;
  lodash.noConflict = noConflict;
  lodash.object = object;
  lodash.omit = omit;
  lodash.once = once;
  lodash.pairs = pairs;
  lodash.partial = partial;
  lodash.pick = pick;
  lodash.pluck = pluck;
  lodash.random = random;
  lodash.range = range;
  lodash.reduce = reduce;
  lodash.reduceRight = reduceRight;
  lodash.reject = reject;
  lodash.rest = rest;
  lodash.result = result;
  lodash.shuffle = shuffle;
  lodash.size = size;
  lodash.some = some;
  lodash.sortBy = sortBy;
  lodash.sortedIndex = sortedIndex;
  lodash.tap = tap;
  lodash.template = template;
  lodash.throttle = throttle;
  lodash.times = times;
  lodash.toArray = toArray;
  lodash.unescape = unescape;
  lodash.union = union;
  lodash.uniq = uniq;
  lodash.uniqueId = uniqueId;
  lodash.values = values;
  lodash.where = where;
  lodash.without = without;
  lodash.wrap = wrap;
  lodash.zip = zip;

  // assign aliases
  lodash.all = every;
  lodash.any = some;
  lodash.collect = map;
  lodash.detect = find;
  lodash.drop = rest;
  lodash.each = forEach;
  lodash.foldl = reduce;
  lodash.foldr = reduceRight;
  lodash.head = first;
  lodash.include = contains;
  lodash.inject = reduce;
  lodash.methods = functions;
  lodash.select = filter;
  lodash.tail = rest;
  lodash.take = first;
  lodash.unique = uniq;

  // add pseudo private properties used and removed during the build process
  lodash._iteratorTemplate = iteratorTemplate;
  lodash._shimKeys = shimKeys;

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

  // assign private `LoDash` constructor's prototype
  LoDash.prototype = lodash.prototype;

  // add all static functions to `LoDash.prototype`
  mixin(lodash);

  // add `LoDash.prototype.chain` after calling `mixin()` to avoid overwriting
  // it with the wrapped `lodash.chain`
  LoDash.prototype.chain = wrapperChain;
  LoDash.prototype.value = wrapperValue;

  // add all mutator Array functions to the wrapper.
  forEach(['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], function(methodName) {
    var func = ArrayProto[methodName];

    LoDash.prototype[methodName] = function() {
      var value = this.__wrapped__;
      func.apply(value, arguments);

      // avoid array-like object bugs with `Array#shift` and `Array#splice` in
      // Firefox < 10 and IE < 9
      if (hasObjectSpliceBug && value.length === 0) {
        delete value[0];
      }
      if (this.__chain__) {
        value = new LoDash(value);
        value.__chain__ = true;
      }
      return value;
    };
  });

  // add all accessor Array functions to the wrapper.
  forEach(['concat', 'join', 'slice'], function(methodName) {
    var func = ArrayProto[methodName];

    LoDash.prototype[methodName] = function() {
      var value = this.__wrapped__,
          result = func.apply(value, arguments);

      if (this.__chain__) {
        result = new LoDash(result);
        result.__chain__ = true;
      }
      return result;
    };
  });

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

  // expose Lo-Dash
  // some AMD build optimizers, like r.js, check for specific condition patterns like the following:
  if (typeof define == 'function' && typeof define.amd == 'object' && define.amd) {
    // Expose Lo-Dash to the global object even when an AMD loader is present in
    // case Lo-Dash was injected by a third-party script and not intended to be
    // loaded as a module. The global assignment can be reverted in the Lo-Dash
    // module via its `noConflict()` method.
    window._ = lodash;

    // define as an anonymous module so, through path mapping, it can be
    // referenced as the "underscore" module
    define(function() {
      return lodash;
    });
  }
  // check for `exports` after `define` in case a build optimizer adds an `exports` object
  else if (freeExports) {
    // in Node.js or RingoJS v0.8.0+
    if (typeof module == 'object' && module && module.exports == freeExports) {
      (module.exports = lodash)._ = lodash;
    }
    // in Narwhal or RingoJS v0.7.0-
    else {
      freeExports._ = lodash;
    }
  }
  else {
    // in a browser or Rhino
    window._ = lodash;
  }
}(this));