discourse/vendor/assets/javascripts/lodash.js

/**
 * @license
 * Lodash (Custom Build) <https://lodash.com/>
 * Build: `lodash include="each,filter,map,range,first,isEmpty,chain,extend,every,omit,merge,union,sortBy,uniq,intersection,reject,compact,reduce,debounce,throttle,values,pick,keys,flatten,min,max,isArray,delay,isString,isEqual,without,invoke,clone,findIndex,find,groupBy" minus="template" -d -o node_modules/lodash.js`
 * Copyright OpenJS Foundation and other contributors <https://openjsf.org/>
 * Released under MIT license <https://lodash.com/license>
 * Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
 * Copyright Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 */
;(function() {

  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
  var undefined;

  /** Used as the semantic version number. */
  var VERSION = '4.17.13';

  /** Used as the size to enable large array optimizations. */
  var LARGE_ARRAY_SIZE = 200;

  /** Error message constants. */
  var FUNC_ERROR_TEXT = 'Expected a function';

  /** Used to stand-in for `undefined` hash values. */
  var HASH_UNDEFINED = '__lodash_hash_undefined__';

  /** Used as the maximum memoize cache size. */
  var MAX_MEMOIZE_SIZE = 500;

  /** Used as the internal argument placeholder. */
  var PLACEHOLDER = '__lodash_placeholder__';

  /** Used to compose bitmasks for cloning. */
  var CLONE_DEEP_FLAG = 1,
      CLONE_FLAT_FLAG = 2,
      CLONE_SYMBOLS_FLAG = 4;

  /** Used to compose bitmasks for value comparisons. */
  var COMPARE_PARTIAL_FLAG = 1,
      COMPARE_UNORDERED_FLAG = 2;

  /** Used to compose bitmasks for function metadata. */
  var WRAP_BIND_FLAG = 1,
      WRAP_BIND_KEY_FLAG = 2,
      WRAP_CURRY_BOUND_FLAG = 4,
      WRAP_CURRY_FLAG = 8,
      WRAP_CURRY_RIGHT_FLAG = 16,
      WRAP_PARTIAL_FLAG = 32,
      WRAP_PARTIAL_RIGHT_FLAG = 64,
      WRAP_ARY_FLAG = 128,
      WRAP_REARG_FLAG = 256,
      WRAP_FLIP_FLAG = 512;

  /** Used to detect hot functions by number of calls within a span of milliseconds. */
  var HOT_COUNT = 800,
      HOT_SPAN = 16;

  /** Used to indicate the type of lazy iteratees. */
  var LAZY_FILTER_FLAG = 1,
      LAZY_MAP_FLAG = 2,
      LAZY_WHILE_FLAG = 3;

  /** Used as references for various `Number` constants. */
  var INFINITY = 1 / 0,
      MAX_SAFE_INTEGER = 9007199254740991,
      MAX_INTEGER = 1.7976931348623157e+308,
      NAN = 0 / 0;

  /** Used as references for the maximum length and index of an array. */
  var MAX_ARRAY_LENGTH = 4294967295;

  /** Used to associate wrap methods with their bit flags. */
  var wrapFlags = [
    ['ary', WRAP_ARY_FLAG],
    ['bind', WRAP_BIND_FLAG],
    ['bindKey', WRAP_BIND_KEY_FLAG],
    ['curry', WRAP_CURRY_FLAG],
    ['curryRight', WRAP_CURRY_RIGHT_FLAG],
    ['flip', WRAP_FLIP_FLAG],
    ['partial', WRAP_PARTIAL_FLAG],
    ['partialRight', WRAP_PARTIAL_RIGHT_FLAG],
    ['rearg', WRAP_REARG_FLAG]
  ];

  /** `Object#toString` result references. */
  var argsTag = '[object Arguments]',
      arrayTag = '[object Array]',
      asyncTag = '[object AsyncFunction]',
      boolTag = '[object Boolean]',
      dateTag = '[object Date]',
      errorTag = '[object Error]',
      funcTag = '[object Function]',
      genTag = '[object GeneratorFunction]',
      mapTag = '[object Map]',
      numberTag = '[object Number]',
      nullTag = '[object Null]',
      objectTag = '[object Object]',
      promiseTag = '[object Promise]',
      proxyTag = '[object Proxy]',
      regexpTag = '[object RegExp]',
      setTag = '[object Set]',
      stringTag = '[object String]',
      symbolTag = '[object Symbol]',
      undefinedTag = '[object Undefined]',
      weakMapTag = '[object WeakMap]';

  var arrayBufferTag = '[object ArrayBuffer]',
      dataViewTag = '[object DataView]',
      float32Tag = '[object Float32Array]',
      float64Tag = '[object Float64Array]',
      int8Tag = '[object Int8Array]',
      int16Tag = '[object Int16Array]',
      int32Tag = '[object Int32Array]',
      uint8Tag = '[object Uint8Array]',
      uint8ClampedTag = '[object Uint8ClampedArray]',
      uint16Tag = '[object Uint16Array]',
      uint32Tag = '[object Uint32Array]';

  /** Used to match property names within property paths. */
  var reIsDeepProp = /\.|\[(?:[^[\]]*|(["'])(?:(?!\1)[^\\]|\\.)*?\1)\]/,
      reIsPlainProp = /^\w*$/,
      rePropName = /[^.[\]]+|\[(?:(-?\d+(?:\.\d+)?)|(["'])((?:(?!\2)[^\\]|\\.)*?)\2)\]|(?=(?:\.|\[\])(?:\.|\[\]|$))/g;

  /**
   * Used to match `RegExp`
   * [syntax characters](http://ecma-international.org/ecma-262/7.0/#sec-patterns).
   */
  var reRegExpChar = /[\\^$.*+?()[\]{}|]/g;

  /** Used to match leading and trailing whitespace. */
  var reTrim = /^\s+|\s+$/g;

  /** Used to match wrap detail comments. */
  var reWrapComment = /\{(?:\n\/\* \[wrapped with .+\] \*\/)?\n?/,
      reWrapDetails = /\{\n\/\* \[wrapped with (.+)\] \*/,
      reSplitDetails = /,? & /;

  /** Used to match backslashes in property paths. */
  var reEscapeChar = /\\(\\)?/g;

  /** Used to match `RegExp` flags from their coerced string values. */
  var reFlags = /\w*$/;

  /** Used to detect bad signed hexadecimal string values. */
  var reIsBadHex = /^[-+]0x[0-9a-f]+$/i;

  /** Used to detect binary string values. */
  var reIsBinary = /^0b[01]+$/i;

  /** Used to detect host constructors (Safari). */
  var reIsHostCtor = /^\[object .+?Constructor\]$/;

  /** Used to detect octal string values. */
  var reIsOctal = /^0o[0-7]+$/i;

  /** Used to detect unsigned integer values. */
  var reIsUint = /^(?:0|[1-9]\d*)$/;

  /** Used to compose unicode character classes. */
  var rsAstralRange = '\\ud800-\\udfff',
      rsComboMarksRange = '\\u0300-\\u036f',
      reComboHalfMarksRange = '\\ufe20-\\ufe2f',
      rsComboSymbolsRange = '\\u20d0-\\u20ff',
      rsComboRange = rsComboMarksRange + reComboHalfMarksRange + rsComboSymbolsRange,
      rsVarRange = '\\ufe0e\\ufe0f';

  /** Used to compose unicode capture groups. */
  var rsAstral = '[' + rsAstralRange + ']',
      rsCombo = '[' + rsComboRange + ']',
      rsFitz = '\\ud83c[\\udffb-\\udfff]',
      rsModifier = '(?:' + rsCombo + '|' + rsFitz + ')',
      rsNonAstral = '[^' + rsAstralRange + ']',
      rsRegional = '(?:\\ud83c[\\udde6-\\uddff]){2}',
      rsSurrPair = '[\\ud800-\\udbff][\\udc00-\\udfff]',
      rsZWJ = '\\u200d';

  /** Used to compose unicode regexes. */
  var reOptMod = rsModifier + '?',
      rsOptVar = '[' + rsVarRange + ']?',
      rsOptJoin = '(?:' + rsZWJ + '(?:' + [rsNonAstral, rsRegional, rsSurrPair].join('|') + ')' + rsOptVar + reOptMod + ')*',
      rsSeq = rsOptVar + reOptMod + rsOptJoin,
      rsSymbol = '(?:' + [rsNonAstral + rsCombo + '?', rsCombo, rsRegional, rsSurrPair, rsAstral].join('|') + ')';

  /** Used to match [string symbols](https://mathiasbynens.be/notes/javascript-unicode). */
  var reUnicode = RegExp(rsFitz + '(?=' + rsFitz + ')|' + rsSymbol + rsSeq, 'g');

  /** Used to detect strings with [zero-width joiners or code points from the astral planes](http://eev.ee/blog/2015/09/12/dark-corners-of-unicode/). */
  var reHasUnicode = RegExp('[' + rsZWJ + rsAstralRange  + rsComboRange + rsVarRange + ']');

  /** Used to identify `toStringTag` values of typed arrays. */
  var typedArrayTags = {};
  typedArrayTags[float32Tag] = typedArrayTags[float64Tag] =
  typedArrayTags[int8Tag] = typedArrayTags[int16Tag] =
  typedArrayTags[int32Tag] = typedArrayTags[uint8Tag] =
  typedArrayTags[uint8ClampedTag] = typedArrayTags[uint16Tag] =
  typedArrayTags[uint32Tag] = true;
  typedArrayTags[argsTag] = typedArrayTags[arrayTag] =
  typedArrayTags[arrayBufferTag] = typedArrayTags[boolTag] =
  typedArrayTags[dataViewTag] = typedArrayTags[dateTag] =
  typedArrayTags[errorTag] = typedArrayTags[funcTag] =
  typedArrayTags[mapTag] = typedArrayTags[numberTag] =
  typedArrayTags[objectTag] = typedArrayTags[regexpTag] =
  typedArrayTags[setTag] = typedArrayTags[stringTag] =
  typedArrayTags[weakMapTag] = false;

  /** Used to identify `toStringTag` values supported by `_.clone`. */
  var cloneableTags = {};
  cloneableTags[argsTag] = cloneableTags[arrayTag] =
  cloneableTags[arrayBufferTag] = cloneableTags[dataViewTag] =
  cloneableTags[boolTag] = cloneableTags[dateTag] =
  cloneableTags[float32Tag] = cloneableTags[float64Tag] =
  cloneableTags[int8Tag] = cloneableTags[int16Tag] =
  cloneableTags[int32Tag] = cloneableTags[mapTag] =
  cloneableTags[numberTag] = cloneableTags[objectTag] =
  cloneableTags[regexpTag] = cloneableTags[setTag] =
  cloneableTags[stringTag] = cloneableTags[symbolTag] =
  cloneableTags[uint8Tag] = cloneableTags[uint8ClampedTag] =
  cloneableTags[uint16Tag] = cloneableTags[uint32Tag] = true;
  cloneableTags[errorTag] = cloneableTags[funcTag] =
  cloneableTags[weakMapTag] = false;

  /** Built-in method references without a dependency on `root`. */
  var freeParseInt = parseInt;

  /** Detect free variable `global` from Node.js. */
  var freeGlobal = typeof global == 'object' && global && global.Object === Object && global;

  /** Detect free variable `self`. */
  var freeSelf = typeof self == 'object' && self && self.Object === Object && self;

  /** Used as a reference to the global object. */
  var root = freeGlobal || freeSelf || Function('return this')();

  /** Detect free variable `exports`. */
  var freeExports = typeof exports == 'object' && exports && !exports.nodeType && exports;

  /** Detect free variable `module`. */
  var freeModule = freeExports && typeof module == 'object' && module && !module.nodeType && module;

  /** Detect the popular CommonJS extension `module.exports`. */
  var moduleExports = freeModule && freeModule.exports === freeExports;

  /** Detect free variable `process` from Node.js. */
  var freeProcess = moduleExports && freeGlobal.process;

  /** Used to access faster Node.js helpers. */
  var nodeUtil = (function() {
    try {
      // Use `util.types` for Node.js 10+.
      var types = freeModule && freeModule.require && freeModule.require('util').types;

      if (types) {
        return types;
      }

      // Legacy `process.binding('util')` for Node.js < 10.
      return freeProcess && freeProcess.binding && freeProcess.binding('util');
    } catch (e) {}
  }());

  /* Node.js helper references. */
  var nodeIsMap = nodeUtil && nodeUtil.isMap,
      nodeIsSet = nodeUtil && nodeUtil.isSet,
      nodeIsTypedArray = nodeUtil && nodeUtil.isTypedArray;

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

  /**
   * A faster alternative to `Function#apply`, this function invokes `func`
   * with the `this` binding of `thisArg` and the arguments of `args`.
   *
   * @private
   * @param {Function} func The function to invoke.
   * @param {*} thisArg The `this` binding of `func`.
   * @param {Array} args The arguments to invoke `func` with.
   * @returns {*} Returns the result of `func`.
   */
  function apply(func, thisArg, args) {
    switch (args.length) {
      case 0: return func.call(thisArg);
      case 1: return func.call(thisArg, args[0]);
      case 2: return func.call(thisArg, args[0], args[1]);
      case 3: return func.call(thisArg, args[0], args[1], args[2]);
    }
    return func.apply(thisArg, args);
  }

  /**
   * A specialized version of `baseAggregator` for arrays.
   *
   * @private
   * @param {Array} [array] The array to iterate over.
   * @param {Function} setter The function to set `accumulator` values.
   * @param {Function} iteratee The iteratee to transform keys.
   * @param {Object} accumulator The initial aggregated object.
   * @returns {Function} Returns `accumulator`.
   */
  function arrayAggregator(array, setter, iteratee, accumulator) {
    var index = -1,
        length = array == null ? 0 : array.length;

    while (++index < length) {
      var value = array[index];
      setter(accumulator, value, iteratee(value), array);
    }
    return accumulator;
  }

  /**
   * A specialized version of `_.forEach` for arrays without support for
   * iteratee shorthands.
   *
   * @private
   * @param {Array} [array] The array to iterate over.
   * @param {Function} iteratee The function invoked per iteration.
   * @returns {Array} Returns `array`.
   */
  function arrayEach(array, iteratee) {
    var index = -1,
        length = array == null ? 0 : array.length;

    while (++index < length) {
      if (iteratee(array[index], index, array) === false) {
        break;
      }
    }
    return array;
  }

  /**
   * A specialized version of `_.every` for arrays without support for
   * iteratee shorthands.
   *
   * @private
   * @param {Array} [array] The array to iterate over.
   * @param {Function} predicate The function invoked per iteration.
   * @returns {boolean} Returns `true` if all elements pass the predicate check,
   *  else `false`.
   */
  function arrayEvery(array, predicate) {
    var index = -1,
        length = array == null ? 0 : array.length;

    while (++index < length) {
      if (!predicate(array[index], index, array)) {
        return false;
      }
    }
    return true;
  }

  /**
   * A specialized version of `_.filter` for arrays without support for
   * iteratee shorthands.
   *
   * @private
   * @param {Array} [array] The array to iterate over.
   * @param {Function} predicate The function invoked per iteration.
   * @returns {Array} Returns the new filtered array.
   */
  function arrayFilter(array, predicate) {
    var index = -1,
        length = array == null ? 0 : array.length,
        resIndex = 0,
        result = [];

    while (++index < length) {
      var value = array[index];
      if (predicate(value, index, array)) {
        result[resIndex++] = value;
      }
    }
    return result;
  }

  /**
   * A specialized version of `_.includes` for arrays without support for
   * specifying an index to search from.
   *
   * @private
   * @param {Array} [array] The array to inspect.
   * @param {*} target The value to search for.
   * @returns {boolean} Returns `true` if `target` is found, else `false`.
   */
  function arrayIncludes(array, value) {
    var length = array == null ? 0 : array.length;
    return !!length && baseIndexOf(array, value, 0) > -1;
  }

  /**
   * This function is like `arrayIncludes` except that it accepts a comparator.
   *
   * @private
   * @param {Array} [array] The array to inspect.
   * @param {*} target The value to search for.
   * @param {Function} comparator The comparator invoked per element.
   * @returns {boolean} Returns `true` if `target` is found, else `false`.
   */
  function arrayIncludesWith(array, value, comparator) {
    var index = -1,
        length = array == null ? 0 : array.length;

    while (++index < length) {
      if (comparator(value, array[index])) {
        return true;
      }
    }
    return false;
  }

  /**
   * A specialized version of `_.map` for arrays without support for iteratee
   * shorthands.
   *
   * @private
   * @param {Array} [array] The array to iterate over.
   * @param {Function} iteratee The function invoked per iteration.
   * @returns {Array} Returns the new mapped array.
   */
  function arrayMap(array, iteratee) {
    var index = -1,
        length = array == null ? 0 : array.length,
        result = Array(length);

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

  /**
   * Appends the elements of `values` to `array`.
   *
   * @private
   * @param {Array} array The array to modify.
   * @param {Array} values The values to append.
   * @returns {Array} Returns `array`.
   */
  function arrayPush(array, values) {
    var index = -1,
        length = values.length,
        offset = array.length;

    while (++index < length) {
      array[offset + index] = values[index];
    }
    return array;
  }

  /**
   * A specialized version of `_.reduce` for arrays without support for
   * iteratee shorthands.
   *
   * @private
   * @param {Array} [array] The array to iterate over.
   * @param {Function} iteratee The function invoked per iteration.
   * @param {*} [accumulator] The initial value.
   * @param {boolean} [initAccum] Specify using the first element of `array` as
   *  the initial value.
   * @returns {*} Returns the accumulated value.
   */
  function arrayReduce(array, iteratee, accumulator, initAccum) {
    var index = -1,
        length = array == null ? 0 : array.length;

    if (initAccum && length) {
      accumulator = array[++index];
    }
    while (++index < length) {
      accumulator = iteratee(accumulator, array[index], index, array);
    }
    return accumulator;
  }

  /**
   * A specialized version of `_.some` for arrays without support for iteratee
   * shorthands.
   *
   * @private
   * @param {Array} [array] The array to iterate over.
   * @param {Function} predicate The function invoked per iteration.
   * @returns {boolean} Returns `true` if any element passes the predicate check,
   *  else `false`.
   */
  function arraySome(array, predicate) {
    var index = -1,
        length = array == null ? 0 : array.length;

    while (++index < length) {
      if (predicate(array[index], index, array)) {
        return true;
      }
    }
    return false;
  }

  /**
   * Converts an ASCII `string` to an array.
   *
   * @private
   * @param {string} string The string to convert.
   * @returns {Array} Returns the converted array.
   */
  function asciiToArray(string) {
    return string.split('');
  }

  /**
   * The base implementation of `_.findIndex` and `_.findLastIndex` without
   * support for iteratee shorthands.
   *
   * @private
   * @param {Array} array The array to inspect.
   * @param {Function} predicate The function invoked per iteration.
   * @param {number} fromIndex The index to search from.
   * @param {boolean} [fromRight] Specify iterating from right to left.
   * @returns {number} Returns the index of the matched value, else `-1`.
   */
  function baseFindIndex(array, predicate, fromIndex, fromRight) {
    var length = array.length,
        index = fromIndex + (fromRight ? 1 : -1);

    while ((fromRight ? index-- : ++index < length)) {
      if (predicate(array[index], index, array)) {
        return index;
      }
    }
    return -1;
  }

  /**
   * The base implementation of `_.indexOf` without `fromIndex` bounds checks.
   *
   * @private
   * @param {Array} array The array to inspect.
   * @param {*} value The value to search for.
   * @param {number} fromIndex The index to search from.
   * @returns {number} Returns the index of the matched value, else `-1`.
   */
  function baseIndexOf(array, value, fromIndex) {
    return value === value
      ? strictIndexOf(array, value, fromIndex)
      : baseFindIndex(array, baseIsNaN, fromIndex);
  }

  /**
   * The base implementation of `_.isNaN` without support for number objects.
   *
   * @private
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is `NaN`, else `false`.
   */
  function baseIsNaN(value) {
    return value !== value;
  }

  /**
   * The base implementation of `_.property` without support for deep paths.
   *
   * @private
   * @param {string} key The key of the property to get.
   * @returns {Function} Returns the new accessor function.
   */
  function baseProperty(key) {
    return function(object) {
      return object == null ? undefined : object[key];
    };
  }

  /**
   * The base implementation of `_.reduce` and `_.reduceRight`, without support
   * for iteratee shorthands, which iterates over `collection` using `eachFunc`.
   *
   * @private
   * @param {Array|Object} collection The collection to iterate over.
   * @param {Function} iteratee The function invoked per iteration.
   * @param {*} accumulator The initial value.
   * @param {boolean} initAccum Specify using the first or last element of
   *  `collection` as the initial value.
   * @param {Function} eachFunc The function to iterate over `collection`.
   * @returns {*} Returns the accumulated value.
   */
  function baseReduce(collection, iteratee, accumulator, initAccum, eachFunc) {
    eachFunc(collection, function(value, index, collection) {
      accumulator = initAccum
        ? (initAccum = false, value)
        : iteratee(accumulator, value, index, collection);
    });
    return accumulator;
  }

  /**
   * The base implementation of `_.sortBy` which uses `comparer` to define the
   * sort order of `array` and replaces criteria objects with their corresponding
   * values.
   *
   * @private
   * @param {Array} array The array to sort.
   * @param {Function} comparer The function to define sort order.
   * @returns {Array} Returns `array`.
   */
  function baseSortBy(array, comparer) {
    var length = array.length;

    array.sort(comparer);
    while (length--) {
      array[length] = array[length].value;
    }
    return array;
  }

  /**
   * The base implementation of `_.times` without support for iteratee shorthands
   * or max array length checks.
   *
   * @private
   * @param {number} n The number of times to invoke `iteratee`.
   * @param {Function} iteratee The function invoked per iteration.
   * @returns {Array} Returns the array of results.
   */
  function baseTimes(n, iteratee) {
    var index = -1,
        result = Array(n);

    while (++index < n) {
      result[index] = iteratee(index);
    }
    return result;
  }

  /**
   * The base implementation of `_.unary` without support for storing metadata.
   *
   * @private
   * @param {Function} func The function to cap arguments for.
   * @returns {Function} Returns the new capped function.
   */
  function baseUnary(func) {
    return function(value) {
      return func(value);
    };
  }

  /**
   * The base implementation of `_.values` and `_.valuesIn` which creates an
   * array of `object` property values corresponding to the property names
   * of `props`.
   *
   * @private
   * @param {Object} object The object to query.
   * @param {Array} props The property names to get values for.
   * @returns {Object} Returns the array of property values.
   */
  function baseValues(object, props) {
    return arrayMap(props, function(key) {
      return object[key];
    });
  }

  /**
   * Checks if a `cache` value for `key` exists.
   *
   * @private
   * @param {Object} cache The cache to query.
   * @param {string} key The key of the entry to check.
   * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
   */
  function cacheHas(cache, key) {
    return cache.has(key);
  }

  /**
   * Gets the number of `placeholder` occurrences in `array`.
   *
   * @private
   * @param {Array} array The array to inspect.
   * @param {*} placeholder The placeholder to search for.
   * @returns {number} Returns the placeholder count.
   */
  function countHolders(array, placeholder) {
    var length = array.length,
        result = 0;

    while (length--) {
      if (array[length] === placeholder) {
        ++result;
      }
    }
    return result;
  }

  /**
   * Gets the value at `key` of `object`.
   *
   * @private
   * @param {Object} [object] The object to query.
   * @param {string} key The key of the property to get.
   * @returns {*} Returns the property value.
   */
  function getValue(object, key) {
    return object == null ? undefined : object[key];
  }

  /**
   * Checks if `string` contains Unicode symbols.
   *
   * @private
   * @param {string} string The string to inspect.
   * @returns {boolean} Returns `true` if a symbol is found, else `false`.
   */
  function hasUnicode(string) {
    return reHasUnicode.test(string);
  }

  /**
   * Converts `iterator` to an array.
   *
   * @private
   * @param {Object} iterator The iterator to convert.
   * @returns {Array} Returns the converted array.
   */
  function iteratorToArray(iterator) {
    var data,
        result = [];

    while (!(data = iterator.next()).done) {
      result.push(data.value);
    }
    return result;
  }

  /**
   * Converts `map` to its key-value pairs.
   *
   * @private
   * @param {Object} map The map to convert.
   * @returns {Array} Returns the key-value pairs.
   */
  function mapToArray(map) {
    var index = -1,
        result = Array(map.size);

    map.forEach(function(value, key) {
      result[++index] = [key, value];
    });
    return result;
  }

  /**
   * Creates a unary function that invokes `func` with its argument transformed.
   *
   * @private
   * @param {Function} func The function to wrap.
   * @param {Function} transform The argument transform.
   * @returns {Function} Returns the new function.
   */
  function overArg(func, transform) {
    return function(arg) {
      return func(transform(arg));
    };
  }

  /**
   * Replaces all `placeholder` elements in `array` with an internal placeholder
   * and returns an array of their indexes.
   *
   * @private
   * @param {Array} array The array to modify.
   * @param {*} placeholder The placeholder to replace.
   * @returns {Array} Returns the new array of placeholder indexes.
   */
  function replaceHolders(array, placeholder) {
    var index = -1,
        length = array.length,
        resIndex = 0,
        result = [];

    while (++index < length) {
      var value = array[index];
      if (value === placeholder || value === PLACEHOLDER) {
        array[index] = PLACEHOLDER;
        result[resIndex++] = index;
      }
    }
    return result;
  }

  /**
   * Converts `set` to an array of its values.
   *
   * @private
   * @param {Object} set The set to convert.
   * @returns {Array} Returns the values.
   */
  function setToArray(set) {
    var index = -1,
        result = Array(set.size);

    set.forEach(function(value) {
      result[++index] = value;
    });
    return result;
  }

  /**
   * A specialized version of `_.indexOf` which performs strict equality
   * comparisons of values, i.e. `===`.
   *
   * @private
   * @param {Array} array The array to inspect.
   * @param {*} value The value to search for.
   * @param {number} fromIndex The index to search from.
   * @returns {number} Returns the index of the matched value, else `-1`.
   */
  function strictIndexOf(array, value, fromIndex) {
    var index = fromIndex - 1,
        length = array.length;

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

  /**
   * Converts `string` to an array.
   *
   * @private
   * @param {string} string The string to convert.
   * @returns {Array} Returns the converted array.
   */
  function stringToArray(string) {
    return hasUnicode(string)
      ? unicodeToArray(string)
      : asciiToArray(string);
  }

  /**
   * Converts a Unicode `string` to an array.
   *
   * @private
   * @param {string} string The string to convert.
   * @returns {Array} Returns the converted array.
   */
  function unicodeToArray(string) {
    return string.match(reUnicode) || [];
  }

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

  /** Used for built-in method references. */
  var arrayProto = Array.prototype,
      funcProto = Function.prototype,
      objectProto = Object.prototype;

  /** Used to detect overreaching core-js shims. */
  var coreJsData = root['__core-js_shared__'];

  /** Used to resolve the decompiled source of functions. */
  var funcToString = funcProto.toString;

  /** Used to check objects for own properties. */
  var hasOwnProperty = objectProto.hasOwnProperty;

  /** Used to detect methods masquerading as native. */
  var maskSrcKey = (function() {
    var uid = /[^.]+$/.exec(coreJsData && coreJsData.keys && coreJsData.keys.IE_PROTO || '');
    return uid ? ('Symbol(src)_1.' + uid) : '';
  }());

  /**
   * Used to resolve the
   * [`toStringTag`](http://ecma-international.org/ecma-262/7.0/#sec-object.prototype.tostring)
   * of values.
   */
  var nativeObjectToString = objectProto.toString;

  /** Used to infer the `Object` constructor. */
  var objectCtorString = funcToString.call(Object);

  /** Used to detect if a method is native. */
  var reIsNative = RegExp('^' +
    funcToString.call(hasOwnProperty).replace(reRegExpChar, '\\$&')
    .replace(/hasOwnProperty|(function).*?(?=\\\()| for .+?(?=\\\])/g, '$1.*?') + '$'
  );

  /** Built-in value references. */
  var Buffer = moduleExports ? root.Buffer : undefined,
      Symbol = root.Symbol,
      Uint8Array = root.Uint8Array,
      allocUnsafe = Buffer ? Buffer.allocUnsafe : undefined,
      getPrototype = overArg(Object.getPrototypeOf, Object),
      objectCreate = Object.create,
      propertyIsEnumerable = objectProto.propertyIsEnumerable,
      splice = arrayProto.splice,
      spreadableSymbol = Symbol ? Symbol.isConcatSpreadable : undefined,
      symIterator = Symbol ? Symbol.iterator : undefined,
      symToStringTag = Symbol ? Symbol.toStringTag : undefined;

  var defineProperty = (function() {
    try {
      var func = getNative(Object, 'defineProperty');
      func({}, '', {});
      return func;
    } catch (e) {}
  }());

  /* Built-in method references for those with the same name as other `lodash` methods. */
  var nativeCeil = Math.ceil,
      nativeGetSymbols = Object.getOwnPropertySymbols,
      nativeIsBuffer = Buffer ? Buffer.isBuffer : undefined,
      nativeKeys = overArg(Object.keys, Object),
      nativeMax = Math.max,
      nativeMin = Math.min,
      nativeNow = Date.now,
      nativeReverse = arrayProto.reverse;

  /* Built-in method references that are verified to be native. */
  var DataView = getNative(root, 'DataView'),
      Map = getNative(root, 'Map'),
      Promise = getNative(root, 'Promise'),
      Set = getNative(root, 'Set'),
      WeakMap = getNative(root, 'WeakMap'),
      nativeCreate = getNative(Object, 'create');

  /** Used to store function metadata. */
  var metaMap = WeakMap && new WeakMap;

  /** Used to lookup unminified function names. */
  var realNames = {};

  /** Used to detect maps, sets, and weakmaps. */
  var dataViewCtorString = toSource(DataView),
      mapCtorString = toSource(Map),
      promiseCtorString = toSource(Promise),
      setCtorString = toSource(Set),
      weakMapCtorString = toSource(WeakMap);

  /** Used to convert symbols to primitives and strings. */
  var symbolProto = Symbol ? Symbol.prototype : undefined,
      symbolValueOf = symbolProto ? symbolProto.valueOf : undefined,
      symbolToString = symbolProto ? symbolProto.toString : undefined;

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

  /**
   * Creates a `lodash` object which wraps `value` to enable implicit method
   * chain sequences. Methods that operate on and return arrays, collections,
   * and functions can be chained together. Methods that retrieve a single value
   * or may return a primitive value will automatically end the chain sequence
   * and return the unwrapped value. Otherwise, the value must be unwrapped
   * with `_#value`.
   *
   * Explicit chain sequences, which must be unwrapped with `_#value`, may be
   * enabled using `_.chain`.
   *
   * The execution of chained methods is lazy, that is, it's deferred until
   * `_#value` is implicitly or explicitly called.
   *
   * Lazy evaluation allows several methods to support shortcut fusion.
   * Shortcut fusion is an optimization to merge iteratee calls; this avoids
   * the creation of intermediate arrays and can greatly reduce the number of
   * iteratee executions. Sections of a chain sequence qualify for shortcut
   * fusion if the section is applied to an array and iteratees accept only
   * one argument. The heuristic for whether a section qualifies for shortcut
   * fusion is subject to change.
   *
   * Chaining is supported in custom builds as long as the `_#value` method is
   * directly or indirectly included in the build.
   *
   * In addition to lodash methods, wrappers have `Array` and `String` methods.
   *
   * The wrapper `Array` methods are:
   * `concat`, `join`, `pop`, `push`, `shift`, `sort`, `splice`, and `unshift`
   *
   * The wrapper `String` methods are:
   * `replace` and `split`
   *
   * The wrapper methods that support shortcut fusion are:
   * `at`, `compact`, `drop`, `dropRight`, `dropWhile`, `filter`, `find`,
   * `findLast`, `head`, `initial`, `last`, `map`, `reject`, `reverse`, `slice`,
   * `tail`, `take`, `takeRight`, `takeRightWhile`, `takeWhile`, and `toArray`
   *
   * The chainable wrapper methods are:
   * `after`, `ary`, `assign`, `assignIn`, `assignInWith`, `assignWith`, `at`,
   * `before`, `bind`, `bindAll`, `bindKey`, `castArray`, `chain`, `chunk`,
   * `commit`, `compact`, `concat`, `conforms`, `constant`, `countBy`, `create`,
   * `curry`, `debounce`, `defaults`, `defaultsDeep`, `defer`, `delay`,
   * `difference`, `differenceBy`, `differenceWith`, `drop`, `dropRight`,
   * `dropRightWhile`, `dropWhile`, `extend`, `extendWith`, `fill`, `filter`,
   * `flatMap`, `flatMapDeep`, `flatMapDepth`, `flatten`, `flattenDeep`,
   * `flattenDepth`, `flip`, `flow`, `flowRight`, `fromPairs`, `functions`,
   * `functionsIn`, `groupBy`, `initial`, `intersection`, `intersectionBy`,
   * `intersectionWith`, `invert`, `invertBy`, `invokeMap`, `iteratee`, `keyBy`,
   * `keys`, `keysIn`, `map`, `mapKeys`, `mapValues`, `matches`, `matchesProperty`,
   * `memoize`, `merge`, `mergeWith`, `method`, `methodOf`, `mixin`, `negate`,
   * `nthArg`, `omit`, `omitBy`, `once`, `orderBy`, `over`, `overArgs`,
   * `overEvery`, `overSome`, `partial`, `partialRight`, `partition`, `pick`,
   * `pickBy`, `plant`, `property`, `propertyOf`, `pull`, `pullAll`, `pullAllBy`,
   * `pullAllWith`, `pullAt`, `push`, `range`, `rangeRight`, `rearg`, `reject`,
   * `remove`, `rest`, `reverse`, `sampleSize`, `set`, `setWith`, `shuffle`,
   * `slice`, `sort`, `sortBy`, `splice`, `spread`, `tail`, `take`, `takeRight`,
   * `takeRightWhile`, `takeWhile`, `tap`, `throttle`, `thru`, `toArray`,
   * `toPairs`, `toPairsIn`, `toPath`, `toPlainObject`, `transform`, `unary`,
   * `union`, `unionBy`, `unionWith`, `uniq`, `uniqBy`, `uniqWith`, `unset`,
   * `unshift`, `unzip`, `unzipWith`, `update`, `updateWith`, `values`,
   * `valuesIn`, `without`, `wrap`, `xor`, `xorBy`, `xorWith`, `zip`,
   * `zipObject`, `zipObjectDeep`, and `zipWith`
   *
   * The wrapper methods that are **not** chainable by default are:
   * `add`, `attempt`, `camelCase`, `capitalize`, `ceil`, `clamp`, `clone`,
   * `cloneDeep`, `cloneDeepWith`, `cloneWith`, `conformsTo`, `deburr`,
   * `defaultTo`, `divide`, `each`, `eachRight`, `endsWith`, `eq`, `escape`,
   * `escapeRegExp`, `every`, `find`, `findIndex`, `findKey`, `findLast`,
   * `findLastIndex`, `findLastKey`, `first`, `floor`, `forEach`, `forEachRight`,
   * `forIn`, `forInRight`, `forOwn`, `forOwnRight`, `get`, `gt`, `gte`, `has`,
   * `hasIn`, `head`, `identity`, `includes`, `indexOf`, `inRange`, `invoke`,
   * `isArguments`, `isArray`, `isArrayBuffer`, `isArrayLike`, `isArrayLikeObject`,
   * `isBoolean`, `isBuffer`, `isDate`, `isElement`, `isEmpty`, `isEqual`,
   * `isEqualWith`, `isError`, `isFinite`, `isFunction`, `isInteger`, `isLength`,
   * `isMap`, `isMatch`, `isMatchWith`, `isNaN`, `isNative`, `isNil`, `isNull`,
   * `isNumber`, `isObject`, `isObjectLike`, `isPlainObject`, `isRegExp`,
   * `isSafeInteger`, `isSet`, `isString`, `isUndefined`, `isTypedArray`,
   * `isWeakMap`, `isWeakSet`, `join`, `kebabCase`, `last`, `lastIndexOf`,
   * `lowerCase`, `lowerFirst`, `lt`, `lte`, `max`, `maxBy`, `mean`, `meanBy`,
   * `min`, `minBy`, `multiply`, `noConflict`, `noop`, `now`, `nth`, `pad`,
   * `padEnd`, `padStart`, `parseInt`, `pop`, `random`, `reduce`, `reduceRight`,
   * `repeat`, `result`, `round`, `runInContext`, `sample`, `shift`, `size`,
   * `snakeCase`, `some`, `sortedIndex`, `sortedIndexBy`, `sortedLastIndex`,
   * `sortedLastIndexBy`, `startCase`, `startsWith`, `stubArray`, `stubFalse`,
   * `stubObject`, `stubString`, `stubTrue`, `subtract`, `sum`, `sumBy`,
   * `template`, `times`, `toFinite`, `toInteger`, `toJSON`, `toLength`,
   * `toLower`, `toNumber`, `toSafeInteger`, `toString`, `toUpper`, `trim`,
   * `trimEnd`, `trimStart`, `truncate`, `unescape`, `uniqueId`, `upperCase`,
   * `upperFirst`, `value`, and `words`
   *
   * @name _
   * @constructor
   * @category Seq
   * @param {*} value The value to wrap in a `lodash` instance.
   * @returns {Object} Returns the new `lodash` wrapper instance.
   * @example
   *
   * function square(n) {
   *   return n * n;
   * }
   *
   * var wrapped = _([1, 2, 3]);
   *
   * // Returns an unwrapped value.
   * wrapped.reduce(_.add);
   * // => 6
   *
   * // Returns a wrapped value.
   * var squares = wrapped.map(square);
   *
   * _.isArray(squares);
   * // => false
   *
   * _.isArray(squares.value());
   * // => true
   */
  function lodash(value) {
    if (isObjectLike(value) && !isArray(value) && !(value instanceof LazyWrapper)) {
      if (value instanceof LodashWrapper) {
        return value;
      }
      if (hasOwnProperty.call(value, '__wrapped__')) {
        return wrapperClone(value);
      }
    }
    return new LodashWrapper(value);
  }

  /**
   * The base implementation of `_.create` without support for assigning
   * properties to the created object.
   *
   * @private
   * @param {Object} proto The object to inherit from.
   * @returns {Object} Returns the new object.
   */
  var baseCreate = (function() {
    function object() {}
    return function(proto) {
      if (!isObject(proto)) {
        return {};
      }
      if (objectCreate) {
        return objectCreate(proto);
      }
      object.prototype = proto;
      var result = new object;
      object.prototype = undefined;
      return result;
    };
  }());

  /**
   * The function whose prototype chain sequence wrappers inherit from.
   *
   * @private
   */
  function baseLodash() {
    // No operation performed.
  }

  /**
   * The base constructor for creating `lodash` wrapper objects.
   *
   * @private
   * @param {*} value The value to wrap.
   * @param {boolean} [chainAll] Enable explicit method chain sequences.
   */
  function LodashWrapper(value, chainAll) {
    this.__wrapped__ = value;
    this.__actions__ = [];
    this.__chain__ = !!chainAll;
    this.__index__ = 0;
    this.__values__ = undefined;
  }

  // Ensure wrappers are instances of `baseLodash`.
  lodash.prototype = baseLodash.prototype;
  lodash.prototype.constructor = lodash;

  LodashWrapper.prototype = baseCreate(baseLodash.prototype);
  LodashWrapper.prototype.constructor = LodashWrapper;

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

  /**
   * Creates a lazy wrapper object which wraps `value` to enable lazy evaluation.
   *
   * @private
   * @constructor
   * @param {*} value The value to wrap.
   */
  function LazyWrapper(value) {
    this.__wrapped__ = value;
    this.__actions__ = [];
    this.__dir__ = 1;
    this.__filtered__ = false;
    this.__iteratees__ = [];
    this.__takeCount__ = MAX_ARRAY_LENGTH;
    this.__views__ = [];
  }

  /**
   * Creates a clone of the lazy wrapper object.
   *
   * @private
   * @name clone
   * @memberOf LazyWrapper
   * @returns {Object} Returns the cloned `LazyWrapper` object.
   */
  function lazyClone() {
    var result = new LazyWrapper(this.__wrapped__);
    result.__actions__ = copyArray(this.__actions__);
    result.__dir__ = this.__dir__;
    result.__filtered__ = this.__filtered__;
    result.__iteratees__ = copyArray(this.__iteratees__);
    result.__takeCount__ = this.__takeCount__;
    result.__views__ = copyArray(this.__views__);
    return result;
  }

  /**
   * Reverses the direction of lazy iteration.
   *
   * @private
   * @name reverse
   * @memberOf LazyWrapper
   * @returns {Object} Returns the new reversed `LazyWrapper` object.
   */
  function lazyReverse() {
    if (this.__filtered__) {
      var result = new LazyWrapper(this);
      result.__dir__ = -1;
      result.__filtered__ = true;
    } else {
      result = this.clone();
      result.__dir__ *= -1;
    }
    return result;
  }

  /**
   * Extracts the unwrapped value from its lazy wrapper.
   *
   * @private
   * @name value
   * @memberOf LazyWrapper
   * @returns {*} Returns the unwrapped value.
   */
  function lazyValue() {
    var array = this.__wrapped__.value(),
        dir = this.__dir__,
        isArr = isArray(array),
        isRight = dir < 0,
        arrLength = isArr ? array.length : 0,
        view = getView(0, arrLength, this.__views__),
        start = view.start,
        end = view.end,
        length = end - start,
        index = isRight ? end : (start - 1),
        iteratees = this.__iteratees__,
        iterLength = iteratees.length,
        resIndex = 0,
        takeCount = nativeMin(length, this.__takeCount__);

    if (!isArr || (!isRight && arrLength == length && takeCount == length)) {
      return baseWrapperValue(array, this.__actions__);
    }
    var result = [];

    outer:
    while (length-- && resIndex < takeCount) {
      index += dir;

      var iterIndex = -1,
          value = array[index];

      while (++iterIndex < iterLength) {
        var data = iteratees[iterIndex],
            iteratee = data.iteratee,
            type = data.type,
            computed = iteratee(value);

        if (type == LAZY_MAP_FLAG) {
          value = computed;
        } else if (!computed) {
          if (type == LAZY_FILTER_FLAG) {
            continue outer;
          } else {
            break outer;
          }
        }
      }
      result[resIndex++] = value;
    }
    return result;
  }

  // Ensure `LazyWrapper` is an instance of `baseLodash`.
  LazyWrapper.prototype = baseCreate(baseLodash.prototype);
  LazyWrapper.prototype.constructor = LazyWrapper;

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

  /**
   * Creates a hash object.
   *
   * @private
   * @constructor
   * @param {Array} [entries] The key-value pairs to cache.
   */
  function Hash(entries) {
    var index = -1,
        length = entries == null ? 0 : entries.length;

    this.clear();
    while (++index < length) {
      var entry = entries[index];
      this.set(entry[0], entry[1]);
    }
  }

  /**
   * Removes all key-value entries from the hash.
   *
   * @private
   * @name clear
   * @memberOf Hash
   */
  function hashClear() {
    this.__data__ = nativeCreate ? nativeCreate(null) : {};
    this.size = 0;
  }

  /**
   * Removes `key` and its value from the hash.
   *
   * @private
   * @name delete
   * @memberOf Hash
   * @param {Object} hash The hash to modify.
   * @param {string} key The key of the value to remove.
   * @returns {boolean} Returns `true` if the entry was removed, else `false`.
   */
  function hashDelete(key) {
    var result = this.has(key) && delete this.__data__[key];
    this.size -= result ? 1 : 0;
    return result;
  }

  /**
   * Gets the hash value for `key`.
   *
   * @private
   * @name get
   * @memberOf Hash
   * @param {string} key The key of the value to get.
   * @returns {*} Returns the entry value.
   */
  function hashGet(key) {
    var data = this.__data__;
    if (nativeCreate) {
      var result = data[key];
      return result === HASH_UNDEFINED ? undefined : result;
    }
    return hasOwnProperty.call(data, key) ? data[key] : undefined;
  }

  /**
   * Checks if a hash value for `key` exists.
   *
   * @private
   * @name has
   * @memberOf Hash
   * @param {string} key The key of the entry to check.
   * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
   */
  function hashHas(key) {
    var data = this.__data__;
    return nativeCreate ? (data[key] !== undefined) : hasOwnProperty.call(data, key);
  }

  /**
   * Sets the hash `key` to `value`.
   *
   * @private
   * @name set
   * @memberOf Hash
   * @param {string} key The key of the value to set.
   * @param {*} value The value to set.
   * @returns {Object} Returns the hash instance.
   */
  function hashSet(key, value) {
    var data = this.__data__;
    this.size += this.has(key) ? 0 : 1;
    data[key] = (nativeCreate && value === undefined) ? HASH_UNDEFINED : value;
    return this;
  }

  // Add methods to `Hash`.
  Hash.prototype.clear = hashClear;
  Hash.prototype['delete'] = hashDelete;
  Hash.prototype.get = hashGet;
  Hash.prototype.has = hashHas;
  Hash.prototype.set = hashSet;

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

  /**
   * Creates an list cache object.
   *
   * @private
   * @constructor
   * @param {Array} [entries] The key-value pairs to cache.
   */
  function ListCache(entries) {
    var index = -1,
        length = entries == null ? 0 : entries.length;

    this.clear();
    while (++index < length) {
      var entry = entries[index];
      this.set(entry[0], entry[1]);
    }
  }

  /**
   * Removes all key-value entries from the list cache.
   *
   * @private
   * @name clear
   * @memberOf ListCache
   */
  function listCacheClear() {
    this.__data__ = [];
    this.size = 0;
  }

  /**
   * Removes `key` and its value from the list cache.
   *
   * @private
   * @name delete
   * @memberOf ListCache
   * @param {string} key The key of the value to remove.
   * @returns {boolean} Returns `true` if the entry was removed, else `false`.
   */
  function listCacheDelete(key) {
    var data = this.__data__,
        index = assocIndexOf(data, key);

    if (index < 0) {
      return false;
    }
    var lastIndex = data.length - 1;
    if (index == lastIndex) {
      data.pop();
    } else {
      splice.call(data, index, 1);
    }
    --this.size;
    return true;
  }

  /**
   * Gets the list cache value for `key`.
   *
   * @private
   * @name get
   * @memberOf ListCache
   * @param {string} key The key of the value to get.
   * @returns {*} Returns the entry value.
   */
  function listCacheGet(key) {
    var data = this.__data__,
        index = assocIndexOf(data, key);

    return index < 0 ? undefined : data[index][1];
  }

  /**
   * Checks if a list cache value for `key` exists.
   *
   * @private
   * @name has
   * @memberOf ListCache
   * @param {string} key The key of the entry to check.
   * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
   */
  function listCacheHas(key) {
    return assocIndexOf(this.__data__, key) > -1;
  }

  /**
   * Sets the list cache `key` to `value`.
   *
   * @private
   * @name set
   * @memberOf ListCache
   * @param {string} key The key of the value to set.
   * @param {*} value The value to set.
   * @returns {Object} Returns the list cache instance.
   */
  function listCacheSet(key, value) {
    var data = this.__data__,
        index = assocIndexOf(data, key);

    if (index < 0) {
      ++this.size;
      data.push([key, value]);
    } else {
      data[index][1] = value;
    }
    return this;
  }

  // Add methods to `ListCache`.
  ListCache.prototype.clear = listCacheClear;
  ListCache.prototype['delete'] = listCacheDelete;
  ListCache.prototype.get = listCacheGet;
  ListCache.prototype.has = listCacheHas;
  ListCache.prototype.set = listCacheSet;

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

  /**
   * Creates a map cache object to store key-value pairs.
   *
   * @private
   * @constructor
   * @param {Array} [entries] The key-value pairs to cache.
   */
  function MapCache(entries) {
    var index = -1,
        length = entries == null ? 0 : entries.length;

    this.clear();
    while (++index < length) {
      var entry = entries[index];
      this.set(entry[0], entry[1]);
    }
  }

  /**
   * Removes all key-value entries from the map.
   *
   * @private
   * @name clear
   * @memberOf MapCache
   */
  function mapCacheClear() {
    this.size = 0;
    this.__data__ = {
      'hash': new Hash,
      'map': new (Map || ListCache),
      'string': new Hash
    };
  }

  /**
   * Removes `key` and its value from the map.
   *
   * @private
   * @name delete
   * @memberOf MapCache
   * @param {string} key The key of the value to remove.
   * @returns {boolean} Returns `true` if the entry was removed, else `false`.
   */
  function mapCacheDelete(key) {
    var result = getMapData(this, key)['delete'](key);
    this.size -= result ? 1 : 0;
    return result;
  }

  /**
   * Gets the map value for `key`.
   *
   * @private
   * @name get
   * @memberOf MapCache
   * @param {string} key The key of the value to get.
   * @returns {*} Returns the entry value.
   */
  function mapCacheGet(key) {
    return getMapData(this, key).get(key);
  }

  /**
   * Checks if a map value for `key` exists.
   *
   * @private
   * @name has
   * @memberOf MapCache
   * @param {string} key The key of the entry to check.
   * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
   */
  function mapCacheHas(key) {
    return getMapData(this, key).has(key);
  }

  /**
   * Sets the map `key` to `value`.
   *
   * @private
   * @name set
   * @memberOf MapCache
   * @param {string} key The key of the value to set.
   * @param {*} value The value to set.
   * @returns {Object} Returns the map cache instance.
   */
  function mapCacheSet(key, value) {
    var data = getMapData(this, key),
        size = data.size;

    data.set(key, value);
    this.size += data.size == size ? 0 : 1;
    return this;
  }

  // Add methods to `MapCache`.
  MapCache.prototype.clear = mapCacheClear;
  MapCache.prototype['delete'] = mapCacheDelete;
  MapCache.prototype.get = mapCacheGet;
  MapCache.prototype.has = mapCacheHas;
  MapCache.prototype.set = mapCacheSet;

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

  /**
   *
   * Creates an array cache object to store unique values.
   *
   * @private
   * @constructor
   * @param {Array} [values] The values to cache.
   */
  function SetCache(values) {
    var index = -1,
        length = values == null ? 0 : values.length;

    this.__data__ = new MapCache;
    while (++index < length) {
      this.add(values[index]);
    }
  }

  /**
   * Adds `value` to the array cache.
   *
   * @private
   * @name add
   * @memberOf SetCache
   * @alias push
   * @param {*} value The value to cache.
   * @returns {Object} Returns the cache instance.
   */
  function setCacheAdd(value) {
    this.__data__.set(value, HASH_UNDEFINED);
    return this;
  }

  /**
   * Checks if `value` is in the array cache.
   *
   * @private
   * @name has
   * @memberOf SetCache
   * @param {*} value The value to search for.
   * @returns {number} Returns `true` if `value` is found, else `false`.
   */
  function setCacheHas(value) {
    return this.__data__.has(value);
  }

  // Add methods to `SetCache`.
  SetCache.prototype.add = SetCache.prototype.push = setCacheAdd;
  SetCache.prototype.has = setCacheHas;

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

  /**
   * Creates a stack cache object to store key-value pairs.
   *
   * @private
   * @constructor
   * @param {Array} [entries] The key-value pairs to cache.
   */
  function Stack(entries) {
    var data = this.__data__ = new ListCache(entries);
    this.size = data.size;
  }

  /**
   * Removes all key-value entries from the stack.
   *
   * @private
   * @name clear
   * @memberOf Stack
   */
  function stackClear() {
    this.__data__ = new ListCache;
    this.size = 0;
  }

  /**
   * Removes `key` and its value from the stack.
   *
   * @private
   * @name delete
   * @memberOf Stack
   * @param {string} key The key of the value to remove.
   * @returns {boolean} Returns `true` if the entry was removed, else `false`.
   */
  function stackDelete(key) {
    var data = this.__data__,
        result = data['delete'](key);

    this.size = data.size;
    return result;
  }

  /**
   * Gets the stack value for `key`.
   *
   * @private
   * @name get
   * @memberOf Stack
   * @param {string} key The key of the value to get.
   * @returns {*} Returns the entry value.
   */
  function stackGet(key) {
    return this.__data__.get(key);
  }

  /**
   * Checks if a stack value for `key` exists.
   *
   * @private
   * @name has
   * @memberOf Stack
   * @param {string} key The key of the entry to check.
   * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
   */
  function stackHas(key) {
    return this.__data__.has(key);
  }

  /**
   * Sets the stack `key` to `value`.
   *
   * @private
   * @name set
   * @memberOf Stack
   * @param {string} key The key of the value to set.
   * @param {*} value The value to set.
   * @returns {Object} Returns the stack cache instance.
   */
  function stackSet(key, value) {
    var data = this.__data__;
    if (data instanceof ListCache) {
      var pairs = data.__data__;
      if (!Map || (pairs.length < LARGE_ARRAY_SIZE - 1)) {
        pairs.push([key, value]);
        this.size = ++data.size;
        return this;
      }
      data = this.__data__ = new MapCache(pairs);
    }
    data.set(key, value);
    this.size = data.size;
    return this;
  }

  // Add methods to `Stack`.
  Stack.prototype.clear = stackClear;
  Stack.prototype['delete'] = stackDelete;
  Stack.prototype.get = stackGet;
  Stack.prototype.has = stackHas;
  Stack.prototype.set = stackSet;

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

  /**
   * Creates an array of the enumerable property names of the array-like `value`.
   *
   * @private
   * @param {*} value The value to query.
   * @param {boolean} inherited Specify returning inherited property names.
   * @returns {Array} Returns the array of property names.
   */
  function arrayLikeKeys(value, inherited) {
    var isArr = isArray(value),
        isArg = !isArr && isArguments(value),
        isBuff = !isArr && !isArg && isBuffer(value),
        isType = !isArr && !isArg && !isBuff && isTypedArray(value),
        skipIndexes = isArr || isArg || isBuff || isType,
        result = skipIndexes ? baseTimes(value.length, String) : [],
        length = result.length;

    for (var key in value) {
      if ((inherited || hasOwnProperty.call(value, key)) &&
          !(skipIndexes && (
             // Safari 9 has enumerable `arguments.length` in strict mode.
             key == 'length' ||
             // Node.js 0.10 has enumerable non-index properties on buffers.
             (isBuff && (key == 'offset' || key == 'parent')) ||
             // PhantomJS 2 has enumerable non-index properties on typed arrays.
             (isType && (key == 'buffer' || key == 'byteLength' || key == 'byteOffset')) ||
             // Skip index properties.
             isIndex(key, length)
          ))) {
        result.push(key);
      }
    }
    return result;
  }

  /**
   * This function is like `assignValue` except that it doesn't assign
   * `undefined` values.
   *
   * @private
   * @param {Object} object The object to modify.
   * @param {string} key The key of the property to assign.
   * @param {*} value The value to assign.
   */
  function assignMergeValue(object, key, value) {
    if ((value !== undefined && !eq(object[key], value)) ||
        (value === undefined && !(key in object))) {
      baseAssignValue(object, key, value);
    }
  }

  /**
   * Assigns `value` to `key` of `object` if the existing value is not equivalent
   * using [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
   * for equality comparisons.
   *
   * @private
   * @param {Object} object The object to modify.
   * @param {string} key The key of the property to assign.
   * @param {*} value The value to assign.
   */
  function assignValue(object, key, value) {
    var objValue = object[key];
    if (!(hasOwnProperty.call(object, key) && eq(objValue, value)) ||
        (value === undefined && !(key in object))) {
      baseAssignValue(object, key, value);
    }
  }

  /**
   * Gets the index at which the `key` is found in `array` of key-value pairs.
   *
   * @private
   * @param {Array} array The array to inspect.
   * @param {*} key The key to search for.
   * @returns {number} Returns the index of the matched value, else `-1`.
   */
  function assocIndexOf(array, key) {
    var length = array.length;
    while (length--) {
      if (eq(array[length][0], key)) {
        return length;
      }
    }
    return -1;
  }

  /**
   * Aggregates elements of `collection` on `accumulator` with keys transformed
   * by `iteratee` and values set by `setter`.
   *
   * @private
   * @param {Array|Object} collection The collection to iterate over.
   * @param {Function} setter The function to set `accumulator` values.
   * @param {Function} iteratee The iteratee to transform keys.
   * @param {Object} accumulator The initial aggregated object.
   * @returns {Function} Returns `accumulator`.
   */
  function baseAggregator(collection, setter, iteratee, accumulator) {
    baseEach(collection, function(value, key, collection) {
      setter(accumulator, value, iteratee(value), collection);
    });
    return accumulator;
  }

  /**
   * The base implementation of `_.assign` without support for multiple sources
   * or `customizer` functions.
   *
   * @private
   * @param {Object} object The destination object.
   * @param {Object} source The source object.
   * @returns {Object} Returns `object`.
   */
  function baseAssign(object, source) {
    return object && copyObject(source, keys(source), object);
  }

  /**
   * The base implementation of `_.assignIn` without support for multiple sources
   * or `customizer` functions.
   *
   * @private
   * @param {Object} object The destination object.
   * @param {Object} source The source object.
   * @returns {Object} Returns `object`.
   */
  function baseAssignIn(object, source) {
    return object && copyObject(source, keysIn(source), object);
  }

  /**
   * The base implementation of `assignValue` and `assignMergeValue` without
   * value checks.
   *
   * @private
   * @param {Object} object The object to modify.
   * @param {string} key The key of the property to assign.
   * @param {*} value The value to assign.
   */
  function baseAssignValue(object, key, value) {
    if (key == '__proto__' && defineProperty) {
      defineProperty(object, key, {
        'configurable': true,
        'enumerable': true,
        'value': value,
        'writable': true
      });
    } else {
      object[key] = value;
    }
  }

  /**
   * The base implementation of `_.at` without support for individual paths.
   *
   * @private
   * @param {Object} object The object to iterate over.
   * @param {string[]} paths The property paths to pick.
   * @returns {Array} Returns the picked elements.
   */
  function baseAt(object, paths) {
    var index = -1,
        length = paths.length,
        result = Array(length),
        skip = object == null;

    while (++index < length) {
      result[index] = skip ? undefined : get(object, paths[index]);
    }
    return result;
  }

  /**
   * The base implementation of `_.clone` and `_.cloneDeep` which tracks
   * traversed objects.
   *
   * @private
   * @param {*} value The value to clone.
   * @param {boolean} bitmask The bitmask flags.
   *  1 - Deep clone
   *  2 - Flatten inherited properties
   *  4 - Clone symbols
   * @param {Function} [customizer] The function to customize cloning.
   * @param {string} [key] The key of `value`.
   * @param {Object} [object] The parent object of `value`.
   * @param {Object} [stack] Tracks traversed objects and their clone counterparts.
   * @returns {*} Returns the cloned value.
   */
  function baseClone(value, bitmask, customizer, key, object, stack) {
    var result,
        isDeep = bitmask & CLONE_DEEP_FLAG,
        isFlat = bitmask & CLONE_FLAT_FLAG,
        isFull = bitmask & CLONE_SYMBOLS_FLAG;

    if (customizer) {
      result = object ? customizer(value, key, object, stack) : customizer(value);
    }
    if (result !== undefined) {
      return result;
    }
    if (!isObject(value)) {
      return value;
    }
    var isArr = isArray(value);
    if (isArr) {
      result = initCloneArray(value);
      if (!isDeep) {
        return copyArray(value, result);
      }
    } else {
      var tag = getTag(value),
          isFunc = tag == funcTag || tag == genTag;

      if (isBuffer(value)) {
        return cloneBuffer(value, isDeep);
      }
      if (tag == objectTag || tag == argsTag || (isFunc && !object)) {
        result = (isFlat || isFunc) ? {} : initCloneObject(value);
        if (!isDeep) {
          return isFlat
            ? copySymbolsIn(value, baseAssignIn(result, value))
            : copySymbols(value, baseAssign(result, value));
        }
      } else {
        if (!cloneableTags[tag]) {
          return object ? value : {};
        }
        result = initCloneByTag(value, tag, isDeep);
      }
    }
    // Check for circular references and return its corresponding clone.
    stack || (stack = new Stack);
    var stacked = stack.get(value);
    if (stacked) {
      return stacked;
    }
    stack.set(value, result);

    if (isSet(value)) {
      value.forEach(function(subValue) {
        result.add(baseClone(subValue, bitmask, customizer, subValue, value, stack));
      });
    } else if (isMap(value)) {
      value.forEach(function(subValue, key) {
        result.set(key, baseClone(subValue, bitmask, customizer, key, value, stack));
      });
    }

    var keysFunc = isFull
      ? (isFlat ? getAllKeysIn : getAllKeys)
      : (isFlat ? keysIn : keys);

    var props = isArr ? undefined : keysFunc(value);
    arrayEach(props || value, function(subValue, key) {
      if (props) {
        key = subValue;
        subValue = value[key];
      }
      // Recursively populate clone (susceptible to call stack limits).
      assignValue(result, key, baseClone(subValue, bitmask, customizer, key, value, stack));
    });
    return result;
  }

  /**
   * The base implementation of `_.delay` and `_.defer` which accepts `args`
   * to provide to `func`.
   *
   * @private
   * @param {Function} func The function to delay.
   * @param {number} wait The number of milliseconds to delay invocation.
   * @param {Array} args The arguments to provide to `func`.
   * @returns {number|Object} Returns the timer id or timeout object.
   */
  function baseDelay(func, wait, args) {
    if (typeof func != 'function') {
      throw new TypeError(FUNC_ERROR_TEXT);
    }
    return setTimeout(function() { func.apply(undefined, args); }, wait);
  }

  /**
   * The base implementation of methods like `_.difference` without support
   * for excluding multiple arrays or iteratee shorthands.
   *
   * @private
   * @param {Array} array The array to inspect.
   * @param {Array} values The values to exclude.
   * @param {Function} [iteratee] The iteratee invoked per element.
   * @param {Function} [comparator] The comparator invoked per element.
   * @returns {Array} Returns the new array of filtered values.
   */
  function baseDifference(array, values, iteratee, comparator) {
    var index = -1,
        includes = arrayIncludes,
        isCommon = true,
        length = array.length,
        result = [],
        valuesLength = values.length;

    if (!length) {
      return result;
    }
    if (iteratee) {
      values = arrayMap(values, baseUnary(iteratee));
    }
    if (comparator) {
      includes = arrayIncludesWith;
      isCommon = false;
    }
    else if (values.length >= LARGE_ARRAY_SIZE) {
      includes = cacheHas;
      isCommon = false;
      values = new SetCache(values);
    }
    outer:
    while (++index < length) {
      var value = array[index],
          computed = iteratee == null ? value : iteratee(value);

      value = (comparator || value !== 0) ? value : 0;
      if (isCommon && computed === computed) {
        var valuesIndex = valuesLength;
        while (valuesIndex--) {
          if (values[valuesIndex] === computed) {
            continue outer;
          }
        }
        result.push(value);
      }
      else if (!includes(values, computed, comparator)) {
        result.push(value);
      }
    }
    return result;
  }

  /**
   * The base implementation of `_.forEach` without support for iteratee shorthands.
   *
   * @private
   * @param {Array|Object} collection The collection to iterate over.
   * @param {Function} iteratee The function invoked per iteration.
   * @returns {Array|Object} Returns `collection`.
   */
  var baseEach = createBaseEach(baseForOwn);

  /**
   * The base implementation of `_.every` without support for iteratee shorthands.
   *
   * @private
   * @param {Array|Object} collection The collection to iterate over.
   * @param {Function} predicate The function invoked per iteration.
   * @returns {boolean} Returns `true` if all elements pass the predicate check,
   *  else `false`
   */
  function baseEvery(collection, predicate) {
    var result = true;
    baseEach(collection, function(value, index, collection) {
      result = !!predicate(value, index, collection);
      return result;
    });
    return result;
  }

  /**
   * The base implementation of methods like `_.max` and `_.min` which accepts a
   * `comparator` to determine the extremum value.
   *
   * @private
   * @param {Array} array The array to iterate over.
   * @param {Function} iteratee The iteratee invoked per iteration.
   * @param {Function} comparator The comparator used to compare values.
   * @returns {*} Returns the extremum value.
   */
  function baseExtremum(array, iteratee, comparator) {
    var index = -1,
        length = array.length;

    while (++index < length) {
      var value = array[index],
          current = iteratee(value);

      if (current != null && (computed === undefined
            ? (current === current && !isSymbol(current))
            : comparator(current, computed)
          )) {
        var computed = current,
            result = value;
      }
    }
    return result;
  }

  /**
   * The base implementation of `_.filter` without support for iteratee shorthands.
   *
   * @private
   * @param {Array|Object} collection The collection to iterate over.
   * @param {Function} predicate The function invoked per iteration.
   * @returns {Array} Returns the new filtered array.
   */
  function baseFilter(collection, predicate) {
    var result = [];
    baseEach(collection, function(value, index, collection) {
      if (predicate(value, index, collection)) {
        result.push(value);
      }
    });
    return result;
  }

  /**
   * The base implementation of `_.flatten` with support for restricting flattening.
   *
   * @private
   * @param {Array} array The array to flatten.
   * @param {number} depth The maximum recursion depth.
   * @param {boolean} [predicate=isFlattenable] The function invoked per iteration.
   * @param {boolean} [isStrict] Restrict to values that pass `predicate` checks.
   * @param {Array} [result=[]] The initial result value.
   * @returns {Array} Returns the new flattened array.
   */
  function baseFlatten(array, depth, predicate, isStrict, result) {
    var index = -1,
        length = array.length;

    predicate || (predicate = isFlattenable);
    result || (result = []);

    while (++index < length) {
      var value = array[index];
      if (depth > 0 && predicate(value)) {
        if (depth > 1) {
          // Recursively flatten arrays (susceptible to call stack limits).
          baseFlatten(value, depth - 1, predicate, isStrict, result);
        } else {
          arrayPush(result, value);
        }
      } else if (!isStrict) {
        result[result.length] = value;
      }
    }
    return result;
  }

  /**
   * The base implementation of `baseForOwn` which iterates over `object`
   * properties returned by `keysFunc` and invokes `iteratee` for each property.
   * Iteratee functions may exit iteration early by explicitly returning `false`.
   *
   * @private
   * @param {Object} object The object to iterate over.
   * @param {Function} iteratee The function invoked per iteration.
   * @param {Function} keysFunc The function to get the keys of `object`.
   * @returns {Object} Returns `object`.
   */
  var baseFor = createBaseFor();

  /**
   * The base implementation of `_.forOwn` without support for iteratee shorthands.
   *
   * @private
   * @param {Object} object The object to iterate over.
   * @param {Function} iteratee The function invoked per iteration.
   * @returns {Object} Returns `object`.
   */
  function baseForOwn(object, iteratee) {
    return object && baseFor(object, iteratee, keys);
  }

  /**
   * The base implementation of `_.functions` which creates an array of
   * `object` function property names filtered from `props`.
   *
   * @private
   * @param {Object} object The object to inspect.
   * @param {Array} props The property names to filter.
   * @returns {Array} Returns the function names.
   */
  function baseFunctions(object, props) {
    return arrayFilter(props, function(key) {
      return isFunction(object[key]);
    });
  }

  /**
   * The base implementation of `_.get` without support for default values.
   *
   * @private
   * @param {Object} object The object to query.
   * @param {Array|string} path The path of the property to get.
   * @returns {*} Returns the resolved value.
   */
  function baseGet(object, path) {
    path = castPath(path, object);

    var index = 0,
        length = path.length;

    while (object != null && index < length) {
      object = object[toKey(path[index++])];
    }
    return (index && index == length) ? object : undefined;
  }

  /**
   * The base implementation of `getAllKeys` and `getAllKeysIn` which uses
   * `keysFunc` and `symbolsFunc` to get the enumerable property names and
   * symbols of `object`.
   *
   * @private
   * @param {Object} object The object to query.
   * @param {Function} keysFunc The function to get the keys of `object`.
   * @param {Function} symbolsFunc The function to get the symbols of `object`.
   * @returns {Array} Returns the array of property names and symbols.
   */
  function baseGetAllKeys(object, keysFunc, symbolsFunc) {
    var result = keysFunc(object);
    return isArray(object) ? result : arrayPush(result, symbolsFunc(object));
  }

  /**
   * The base implementation of `getTag` without fallbacks for buggy environments.
   *
   * @private
   * @param {*} value The value to query.
   * @returns {string} Returns the `toStringTag`.
   */
  function baseGetTag(value) {
    if (value == null) {
      return value === undefined ? undefinedTag : nullTag;
    }
    return (symToStringTag && symToStringTag in Object(value))
      ? getRawTag(value)
      : objectToString(value);
  }

  /**
   * The base implementation of `_.gt` which doesn't coerce arguments.
   *
   * @private
   * @param {*} value The value to compare.
   * @param {*} other The other value to compare.
   * @returns {boolean} Returns `true` if `value` is greater than `other`,
   *  else `false`.
   */
  function baseGt(value, other) {
    return value > other;
  }

  /**
   * The base implementation of `_.hasIn` without support for deep paths.
   *
   * @private
   * @param {Object} [object] The object to query.
   * @param {Array|string} key The key to check.
   * @returns {boolean} Returns `true` if `key` exists, else `false`.
   */
  function baseHasIn(object, key) {
    return object != null && key in Object(object);
  }

  /**
   * The base implementation of methods like `_.intersection`, without support
   * for iteratee shorthands, that accepts an array of arrays to inspect.
   *
   * @private
   * @param {Array} arrays The arrays to inspect.
   * @param {Function} [iteratee] The iteratee invoked per element.
   * @param {Function} [comparator] The comparator invoked per element.
   * @returns {Array} Returns the new array of shared values.
   */
  function baseIntersection(arrays, iteratee, comparator) {
    var includes = comparator ? arrayIncludesWith : arrayIncludes,
        length = arrays[0].length,
        othLength = arrays.length,
        othIndex = othLength,
        caches = Array(othLength),
        maxLength = Infinity,
        result = [];

    while (othIndex--) {
      var array = arrays[othIndex];
      if (othIndex && iteratee) {
        array = arrayMap(array, baseUnary(iteratee));
      }
      maxLength = nativeMin(array.length, maxLength);
      caches[othIndex] = !comparator && (iteratee || (length >= 120 && array.length >= 120))
        ? new SetCache(othIndex && array)
        : undefined;
    }
    array = arrays[0];

    var index = -1,
        seen = caches[0];

    outer:
    while (++index < length && result.length < maxLength) {
      var value = array[index],
          computed = iteratee ? iteratee(value) : value;

      value = (comparator || value !== 0) ? value : 0;
      if (!(seen
            ? cacheHas(seen, computed)
            : includes(result, computed, comparator)
          )) {
        othIndex = othLength;
        while (--othIndex) {
          var cache = caches[othIndex];
          if (!(cache
                ? cacheHas(cache, computed)
                : includes(arrays[othIndex], computed, comparator))
              ) {
            continue outer;
          }
        }
        if (seen) {
          seen.push(computed);
        }
        result.push(value);
      }
    }
    return result;
  }

  /**
   * The base implementation of `_.invoke` without support for individual
   * method arguments.
   *
   * @private
   * @param {Object} object The object to query.
   * @param {Array|string} path The path of the method to invoke.
   * @param {Array} args The arguments to invoke the method with.
   * @returns {*} Returns the result of the invoked method.
   */
  function baseInvoke(object, path, args) {
    path = castPath(path, object);
    object = parent(object, path);
    var func = object == null ? object : object[toKey(last(path))];
    return func == null ? undefined : apply(func, object, args);
  }

  /**
   * The base implementation of `_.isArguments`.
   *
   * @private
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is an `arguments` object,
   */
  function baseIsArguments(value) {
    return isObjectLike(value) && baseGetTag(value) == argsTag;
  }

  /**
   * The base implementation of `_.isEqual` which supports partial comparisons
   * and tracks traversed objects.
   *
   * @private
   * @param {*} value The value to compare.
   * @param {*} other The other value to compare.
   * @param {boolean} bitmask The bitmask flags.
   *  1 - Unordered comparison
   *  2 - Partial comparison
   * @param {Function} [customizer] The function to customize comparisons.
   * @param {Object} [stack] Tracks traversed `value` and `other` objects.
   * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
   */
  function baseIsEqual(value, other, bitmask, customizer, stack) {
    if (value === other) {
      return true;
    }
    if (value == null || other == null || (!isObjectLike(value) && !isObjectLike(other))) {
      return value !== value && other !== other;
    }
    return baseIsEqualDeep(value, other, bitmask, customizer, baseIsEqual, stack);
  }

  /**
   * A specialized version of `baseIsEqual` for arrays and objects which performs
   * deep comparisons and tracks traversed objects enabling objects with circular
   * references to be compared.
   *
   * @private
   * @param {Object} object The object to compare.
   * @param {Object} other The other object to compare.
   * @param {number} bitmask The bitmask flags. See `baseIsEqual` for more details.
   * @param {Function} customizer The function to customize comparisons.
   * @param {Function} equalFunc The function to determine equivalents of values.
   * @param {Object} [stack] Tracks traversed `object` and `other` objects.
   * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
   */
  function baseIsEqualDeep(object, other, bitmask, customizer, equalFunc, stack) {
    var objIsArr = isArray(object),
        othIsArr = isArray(other),
        objTag = objIsArr ? arrayTag : getTag(object),
        othTag = othIsArr ? arrayTag : getTag(other);

    objTag = objTag == argsTag ? objectTag : objTag;
    othTag = othTag == argsTag ? objectTag : othTag;

    var objIsObj = objTag == objectTag,
        othIsObj = othTag == objectTag,
        isSameTag = objTag == othTag;

    if (isSameTag && isBuffer(object)) {
      if (!isBuffer(other)) {
        return false;
      }
      objIsArr = true;
      objIsObj = false;
    }
    if (isSameTag && !objIsObj) {
      stack || (stack = new Stack);
      return (objIsArr || isTypedArray(object))
        ? equalArrays(object, other, bitmask, customizer, equalFunc, stack)
        : equalByTag(object, other, objTag, bitmask, customizer, equalFunc, stack);
    }
    if (!(bitmask & COMPARE_PARTIAL_FLAG)) {
      var objIsWrapped = objIsObj && hasOwnProperty.call(object, '__wrapped__'),
          othIsWrapped = othIsObj && hasOwnProperty.call(other, '__wrapped__');

      if (objIsWrapped || othIsWrapped) {
        var objUnwrapped = objIsWrapped ? object.value() : object,
            othUnwrapped = othIsWrapped ? other.value() : other;

        stack || (stack = new Stack);
        return equalFunc(objUnwrapped, othUnwrapped, bitmask, customizer, stack);
      }
    }
    if (!isSameTag) {
      return false;
    }
    stack || (stack = new Stack);
    return equalObjects(object, other, bitmask, customizer, equalFunc, stack);
  }

  /**
   * The base implementation of `_.isMap` without Node.js optimizations.
   *
   * @private
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is a map, else `false`.
   */
  function baseIsMap(value) {
    return isObjectLike(value) && getTag(value) == mapTag;
  }

  /**
   * The base implementation of `_.isMatch` without support for iteratee shorthands.
   *
   * @private
   * @param {Object} object The object to inspect.
   * @param {Object} source The object of property values to match.
   * @param {Array} matchData The property names, values, and compare flags to match.
   * @param {Function} [customizer] The function to customize comparisons.
   * @returns {boolean} Returns `true` if `object` is a match, else `false`.
   */
  function baseIsMatch(object, source, matchData, customizer) {
    var index = matchData.length,
        length = index,
        noCustomizer = !customizer;

    if (object == null) {
      return !length;
    }
    object = Object(object);
    while (index--) {
      var data = matchData[index];
      if ((noCustomizer && data[2])
            ? data[1] !== object[data[0]]
            : !(data[0] in object)
          ) {
        return false;
      }
    }
    while (++index < length) {
      data = matchData[index];
      var key = data[0],
          objValue = object[key],
          srcValue = data[1];

      if (noCustomizer && data[2]) {
        if (objValue === undefined && !(key in object)) {
          return false;
        }
      } else {
        var stack = new Stack;
        if (customizer) {
          var result = customizer(objValue, srcValue, key, object, source, stack);
        }
        if (!(result === undefined
              ? baseIsEqual(srcValue, objValue, COMPARE_PARTIAL_FLAG | COMPARE_UNORDERED_FLAG, customizer, stack)
              : result
            )) {
          return false;
        }
      }
    }
    return true;
  }

  /**
   * The base implementation of `_.isNative` without bad shim checks.
   *
   * @private
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is a native function,
   *  else `false`.
   */
  function baseIsNative(value) {
    if (!isObject(value) || isMasked(value)) {
      return false;
    }
    var pattern = isFunction(value) ? reIsNative : reIsHostCtor;
    return pattern.test(toSource(value));
  }

  /**
   * The base implementation of `_.isSet` without Node.js optimizations.
   *
   * @private
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is a set, else `false`.
   */
  function baseIsSet(value) {
    return isObjectLike(value) && getTag(value) == setTag;
  }

  /**
   * The base implementation of `_.isTypedArray` without Node.js optimizations.
   *
   * @private
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is a typed array, else `false`.
   */
  function baseIsTypedArray(value) {
    return isObjectLike(value) &&
      isLength(value.length) && !!typedArrayTags[baseGetTag(value)];
  }

  /**
   * The base implementation of `_.iteratee`.
   *
   * @private
   * @param {*} [value=_.identity] The value to convert to an iteratee.
   * @returns {Function} Returns the iteratee.
   */
  function baseIteratee(value) {
    // Don't store the `typeof` result in a variable to avoid a JIT bug in Safari 9.
    // See https://bugs.webkit.org/show_bug.cgi?id=156034 for more details.
    if (typeof value == 'function') {
      return value;
    }
    if (value == null) {
      return identity;
    }
    if (typeof value == 'object') {
      return isArray(value)
        ? baseMatchesProperty(value[0], value[1])
        : baseMatches(value);
    }
    return property(value);
  }

  /**
   * The base implementation of `_.keys` which doesn't treat sparse arrays as dense.
   *
   * @private
   * @param {Object} object The object to query.
   * @returns {Array} Returns the array of property names.
   */
  function baseKeys(object) {
    if (!isPrototype(object)) {
      return nativeKeys(object);
    }
    var result = [];
    for (var key in Object(object)) {
      if (hasOwnProperty.call(object, key) && key != 'constructor') {
        result.push(key);
      }
    }
    return result;
  }

  /**
   * The base implementation of `_.keysIn` which doesn't treat sparse arrays as dense.
   *
   * @private
   * @param {Object} object The object to query.
   * @returns {Array} Returns the array of property names.
   */
  function baseKeysIn(object) {
    if (!isObject(object)) {
      return nativeKeysIn(object);
    }
    var isProto = isPrototype(object),
        result = [];

    for (var key in object) {
      if (!(key == 'constructor' && (isProto || !hasOwnProperty.call(object, key)))) {
        result.push(key);
      }
    }
    return result;
  }

  /**
   * The base implementation of `_.lt` which doesn't coerce arguments.
   *
   * @private
   * @param {*} value The value to compare.
   * @param {*} other The other value to compare.
   * @returns {boolean} Returns `true` if `value` is less than `other`,
   *  else `false`.
   */
  function baseLt(value, other) {
    return value < other;
  }

  /**
   * The base implementation of `_.map` without support for iteratee shorthands.
   *
   * @private
   * @param {Array|Object} collection The collection to iterate over.
   * @param {Function} iteratee The function invoked per iteration.
   * @returns {Array} Returns the new mapped array.
   */
  function baseMap(collection, iteratee) {
    var index = -1,
        result = isArrayLike(collection) ? Array(collection.length) : [];

    baseEach(collection, function(value, key, collection) {
      result[++index] = iteratee(value, key, collection);
    });
    return result;
  }

  /**
   * The base implementation of `_.matches` which doesn't clone `source`.
   *
   * @private
   * @param {Object} source The object of property values to match.
   * @returns {Function} Returns the new spec function.
   */
  function baseMatches(source) {
    var matchData = getMatchData(source);
    if (matchData.length == 1 && matchData[0][2]) {
      return matchesStrictComparable(matchData[0][0], matchData[0][1]);
    }
    return function(object) {
      return object === source || baseIsMatch(object, source, matchData);
    };
  }

  /**
   * The base implementation of `_.matchesProperty` which doesn't clone `srcValue`.
   *
   * @private
   * @param {string} path The path of the property to get.
   * @param {*} srcValue The value to match.
   * @returns {Function} Returns the new spec function.
   */
  function baseMatchesProperty(path, srcValue) {
    if (isKey(path) && isStrictComparable(srcValue)) {
      return matchesStrictComparable(toKey(path), srcValue);
    }
    return function(object) {
      var objValue = get(object, path);
      return (objValue === undefined && objValue === srcValue)
        ? hasIn(object, path)
        : baseIsEqual(srcValue, objValue, COMPARE_PARTIAL_FLAG | COMPARE_UNORDERED_FLAG);
    };
  }

  /**
   * The base implementation of `_.merge` without support for multiple sources.
   *
   * @private
   * @param {Object} object The destination object.
   * @param {Object} source The source object.
   * @param {number} srcIndex The index of `source`.
   * @param {Function} [customizer] The function to customize merged values.
   * @param {Object} [stack] Tracks traversed source values and their merged
   *  counterparts.
   */
  function baseMerge(object, source, srcIndex, customizer, stack) {
    if (object === source) {
      return;
    }
    baseFor(source, function(srcValue, key) {
      stack || (stack = new Stack);
      if (isObject(srcValue)) {
        baseMergeDeep(object, source, key, srcIndex, baseMerge, customizer, stack);
      }
      else {
        var newValue = customizer
          ? customizer(safeGet(object, key), srcValue, (key + ''), object, source, stack)
          : undefined;

        if (newValue === undefined) {
          newValue = srcValue;
        }
        assignMergeValue(object, key, newValue);
      }
    }, keysIn);
  }

  /**
   * A specialized version of `baseMerge` for arrays and objects which performs
   * deep merges and tracks traversed objects enabling objects with circular
   * references to be merged.
   *
   * @private
   * @param {Object} object The destination object.
   * @param {Object} source The source object.
   * @param {string} key The key of the value to merge.
   * @param {number} srcIndex The index of `source`.
   * @param {Function} mergeFunc The function to merge values.
   * @param {Function} [customizer] The function to customize assigned values.
   * @param {Object} [stack] Tracks traversed source values and their merged
   *  counterparts.
   */
  function baseMergeDeep(object, source, key, srcIndex, mergeFunc, customizer, stack) {
    var objValue = safeGet(object, key),
        srcValue = safeGet(source, key),
        stacked = stack.get(srcValue);

    if (stacked) {
      assignMergeValue(object, key, stacked);
      return;
    }
    var newValue = customizer
      ? customizer(objValue, srcValue, (key + ''), object, source, stack)
      : undefined;

    var isCommon = newValue === undefined;

    if (isCommon) {
      var isArr = isArray(srcValue),
          isBuff = !isArr && isBuffer(srcValue),
          isTyped = !isArr && !isBuff && isTypedArray(srcValue);

      newValue = srcValue;
      if (isArr || isBuff || isTyped) {
        if (isArray(objValue)) {
          newValue = objValue;
        }
        else if (isArrayLikeObject(objValue)) {
          newValue = copyArray(objValue);
        }
        else if (isBuff) {
          isCommon = false;
          newValue = cloneBuffer(srcValue, true);
        }
        else if (isTyped) {
          isCommon = false;
          newValue = cloneTypedArray(srcValue, true);
        }
        else {
          newValue = [];
        }
      }
      else if (isPlainObject(srcValue) || isArguments(srcValue)) {
        newValue = objValue;
        if (isArguments(objValue)) {
          newValue = toPlainObject(objValue);
        }
        else if (!isObject(objValue) || isFunction(objValue)) {
          newValue = initCloneObject(srcValue);
        }
      }
      else {
        isCommon = false;
      }
    }
    if (isCommon) {
      // Recursively merge objects and arrays (susceptible to call stack limits).
      stack.set(srcValue, newValue);
      mergeFunc(newValue, srcValue, srcIndex, customizer, stack);
      stack['delete'](srcValue);
    }
    assignMergeValue(object, key, newValue);
  }

  /**
   * The base implementation of `_.orderBy` without param guards.
   *
   * @private
   * @param {Array|Object} collection The collection to iterate over.
   * @param {Function[]|Object[]|string[]} iteratees The iteratees to sort by.
   * @param {string[]} orders The sort orders of `iteratees`.
   * @returns {Array} Returns the new sorted array.
   */
  function baseOrderBy(collection, iteratees, orders) {
    var index = -1;
    iteratees = arrayMap(iteratees.length ? iteratees : [identity], baseUnary(getIteratee()));

    var result = baseMap(collection, function(value, key, collection) {
      var criteria = arrayMap(iteratees, function(iteratee) {
        return iteratee(value);
      });
      return { 'criteria': criteria, 'index': ++index, 'value': value };
    });

    return baseSortBy(result, function(object, other) {
      return compareMultiple(object, other, orders);
    });
  }

  /**
   * The base implementation of `_.pick` without support for individual
   * property identifiers.
   *
   * @private
   * @param {Object} object The source object.
   * @param {string[]} paths The property paths to pick.
   * @returns {Object} Returns the new object.
   */
  function basePick(object, paths) {
    return basePickBy(object, paths, function(value, path) {
      return hasIn(object, path);
    });
  }

  /**
   * The base implementation of  `_.pickBy` without support for iteratee shorthands.
   *
   * @private
   * @param {Object} object The source object.
   * @param {string[]} paths The property paths to pick.
   * @param {Function} predicate The function invoked per property.
   * @returns {Object} Returns the new object.
   */
  function basePickBy(object, paths, predicate) {
    var index = -1,
        length = paths.length,
        result = {};

    while (++index < length) {
      var path = paths[index],
          value = baseGet(object, path);

      if (predicate(value, path)) {
        baseSet(result, castPath(path, object), value);
      }
    }
    return result;
  }

  /**
   * A specialized version of `baseProperty` which supports deep paths.
   *
   * @private
   * @param {Array|string} path The path of the property to get.
   * @returns {Function} Returns the new accessor function.
   */
  function basePropertyDeep(path) {
    return function(object) {
      return baseGet(object, path);
    };
  }

  /**
   * The base implementation of `_.range` and `_.rangeRight` which doesn't
   * coerce arguments.
   *
   * @private
   * @param {number} start The start of the range.
   * @param {number} end The end of the range.
   * @param {number} step The value to increment or decrement by.
   * @param {boolean} [fromRight] Specify iterating from right to left.
   * @returns {Array} Returns the range of numbers.
   */
  function baseRange(start, end, step, fromRight) {
    var index = -1,
        length = nativeMax(nativeCeil((end - start) / (step || 1)), 0),
        result = Array(length);

    while (length--) {
      result[fromRight ? length : ++index] = start;
      start += step;
    }
    return result;
  }

  /**
   * The base implementation of `_.rest` which doesn't validate or coerce arguments.
   *
   * @private
   * @param {Function} func The function to apply a rest parameter to.
   * @param {number} [start=func.length-1] The start position of the rest parameter.
   * @returns {Function} Returns the new function.
   */
  function baseRest(func, start) {
    return setToString(overRest(func, start, identity), func + '');
  }

  /**
   * The base implementation of `_.set`.
   *
   * @private
   * @param {Object} object The object to modify.
   * @param {Array|string} path The path of the property to set.
   * @param {*} value The value to set.
   * @param {Function} [customizer] The function to customize path creation.
   * @returns {Object} Returns `object`.
   */
  function baseSet(object, path, value, customizer) {
    if (!isObject(object)) {
      return object;
    }
    path = castPath(path, object);

    var index = -1,
        length = path.length,
        lastIndex = length - 1,
        nested = object;

    while (nested != null && ++index < length) {
      var key = toKey(path[index]),
          newValue = value;

      if (index != lastIndex) {
        var objValue = nested[key];
        newValue = customizer ? customizer(objValue, key, nested) : undefined;
        if (newValue === undefined) {
          newValue = isObject(objValue)
            ? objValue
            : (isIndex(path[index + 1]) ? [] : {});
        }
      }
      assignValue(nested, key, newValue);
      nested = nested[key];
    }
    return object;
  }

  /**
   * The base implementation of `setData` without support for hot loop shorting.
   *
   * @private
   * @param {Function} func The function to associate metadata with.
   * @param {*} data The metadata.
   * @returns {Function} Returns `func`.
   */
  var baseSetData = !metaMap ? identity : function(func, data) {
    metaMap.set(func, data);
    return func;
  };

  /**
   * The base implementation of `setToString` without support for hot loop shorting.
   *
   * @private
   * @param {Function} func The function to modify.
   * @param {Function} string The `toString` result.
   * @returns {Function} Returns `func`.
   */
  var baseSetToString = !defineProperty ? identity : function(func, string) {
    return defineProperty(func, 'toString', {
      'configurable': true,
      'enumerable': false,
      'value': constant(string),
      'writable': true
    });
  };

  /**
   * The base implementation of `_.slice` without an iteratee call guard.
   *
   * @private
   * @param {Array} array The array to slice.
   * @param {number} [start=0] The start position.
   * @param {number} [end=array.length] The end position.
   * @returns {Array} Returns the slice of `array`.
   */
  function baseSlice(array, start, end) {
    var index = -1,
        length = array.length;

    if (start < 0) {
      start = -start > length ? 0 : (length + start);
    }
    end = end > length ? length : end;
    if (end < 0) {
      end += length;
    }
    length = start > end ? 0 : ((end - start) >>> 0);
    start >>>= 0;

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

  /**
   * The base implementation of `_.toString` which doesn't convert nullish
   * values to empty strings.
   *
   * @private
   * @param {*} value The value to process.
   * @returns {string} Returns the string.
   */
  function baseToString(value) {
    // Exit early for strings to avoid a performance hit in some environments.
    if (typeof value == 'string') {
      return value;
    }
    if (isArray(value)) {
      // Recursively convert values (susceptible to call stack limits).
      return arrayMap(value, baseToString) + '';
    }
    if (isSymbol(value)) {
      return symbolToString ? symbolToString.call(value) : '';
    }
    var result = (value + '');
    return (result == '0' && (1 / value) == -INFINITY) ? '-0' : result;
  }

  /**
   * The base implementation of `_.uniqBy` without support for iteratee shorthands.
   *
   * @private
   * @param {Array} array The array to inspect.
   * @param {Function} [iteratee] The iteratee invoked per element.
   * @param {Function} [comparator] The comparator invoked per element.
   * @returns {Array} Returns the new duplicate free array.
   */
  function baseUniq(array, iteratee, comparator) {
    var index = -1,
        includes = arrayIncludes,
        length = array.length,
        isCommon = true,
        result = [],
        seen = result;

    if (comparator) {
      isCommon = false;
      includes = arrayIncludesWith;
    }
    else if (length >= LARGE_ARRAY_SIZE) {
      var set = iteratee ? null : createSet(array);
      if (set) {
        return setToArray(set);
      }
      isCommon = false;
      includes = cacheHas;
      seen = new SetCache;
    }
    else {
      seen = iteratee ? [] : result;
    }
    outer:
    while (++index < length) {
      var value = array[index],
          computed = iteratee ? iteratee(value) : value;

      value = (comparator || value !== 0) ? value : 0;
      if (isCommon && computed === computed) {
        var seenIndex = seen.length;
        while (seenIndex--) {
          if (seen[seenIndex] === computed) {
            continue outer;
          }
        }
        if (iteratee) {
          seen.push(computed);
        }
        result.push(value);
      }
      else if (!includes(seen, computed, comparator)) {
        if (seen !== result) {
          seen.push(computed);
        }
        result.push(value);
      }
    }
    return result;
  }

  /**
   * The base implementation of `_.unset`.
   *
   * @private
   * @param {Object} object The object to modify.
   * @param {Array|string} path The property path to unset.
   * @returns {boolean} Returns `true` if the property is deleted, else `false`.
   */
  function baseUnset(object, path) {
    path = castPath(path, object);
    object = parent(object, path);
    return object == null || delete object[toKey(last(path))];
  }

  /**
   * The base implementation of `wrapperValue` which returns the result of
   * performing a sequence of actions on the unwrapped `value`, where each
   * successive action is supplied the return value of the previous.
   *
   * @private
   * @param {*} value The unwrapped value.
   * @param {Array} actions Actions to perform to resolve the unwrapped value.
   * @returns {*} Returns the resolved value.
   */
  function baseWrapperValue(value, actions) {
    var result = value;
    if (result instanceof LazyWrapper) {
      result = result.value();
    }
    return arrayReduce(actions, function(result, action) {
      return action.func.apply(action.thisArg, arrayPush([result], action.args));
    }, result);
  }

  /**
   * Casts `value` to an empty array if it's not an array like object.
   *
   * @private
   * @param {*} value The value to inspect.
   * @returns {Array|Object} Returns the cast array-like object.
   */
  function castArrayLikeObject(value) {
    return isArrayLikeObject(value) ? value : [];
  }

  /**
   * Casts `value` to a path array if it's not one.
   *
   * @private
   * @param {*} value The value to inspect.
   * @param {Object} [object] The object to query keys on.
   * @returns {Array} Returns the cast property path array.
   */
  function castPath(value, object) {
    if (isArray(value)) {
      return value;
    }
    return isKey(value, object) ? [value] : stringToPath(toString(value));
  }

  /**
   * Creates a clone of  `buffer`.
   *
   * @private
   * @param {Buffer} buffer The buffer to clone.
   * @param {boolean} [isDeep] Specify a deep clone.
   * @returns {Buffer} Returns the cloned buffer.
   */
  function cloneBuffer(buffer, isDeep) {
    if (isDeep) {
      return buffer.slice();
    }
    var length = buffer.length,
        result = allocUnsafe ? allocUnsafe(length) : new buffer.constructor(length);

    buffer.copy(result);
    return result;
  }

  /**
   * Creates a clone of `arrayBuffer`.
   *
   * @private
   * @param {ArrayBuffer} arrayBuffer The array buffer to clone.
   * @returns {ArrayBuffer} Returns the cloned array buffer.
   */
  function cloneArrayBuffer(arrayBuffer) {
    var result = new arrayBuffer.constructor(arrayBuffer.byteLength);
    new Uint8Array(result).set(new Uint8Array(arrayBuffer));
    return result;
  }

  /**
   * Creates a clone of `dataView`.
   *
   * @private
   * @param {Object} dataView The data view to clone.
   * @param {boolean} [isDeep] Specify a deep clone.
   * @returns {Object} Returns the cloned data view.
   */
  function cloneDataView(dataView, isDeep) {
    var buffer = isDeep ? cloneArrayBuffer(dataView.buffer) : dataView.buffer;
    return new dataView.constructor(buffer, dataView.byteOffset, dataView.byteLength);
  }

  /**
   * Creates a clone of `regexp`.
   *
   * @private
   * @param {Object} regexp The regexp to clone.
   * @returns {Object} Returns the cloned regexp.
   */
  function cloneRegExp(regexp) {
    var result = new regexp.constructor(regexp.source, reFlags.exec(regexp));
    result.lastIndex = regexp.lastIndex;
    return result;
  }

  /**
   * Creates a clone of the `symbol` object.
   *
   * @private
   * @param {Object} symbol The symbol object to clone.
   * @returns {Object} Returns the cloned symbol object.
   */
  function cloneSymbol(symbol) {
    return symbolValueOf ? Object(symbolValueOf.call(symbol)) : {};
  }

  /**
   * Creates a clone of `typedArray`.
   *
   * @private
   * @param {Object} typedArray The typed array to clone.
   * @param {boolean} [isDeep] Specify a deep clone.
   * @returns {Object} Returns the cloned typed array.
   */
  function cloneTypedArray(typedArray, isDeep) {
    var buffer = isDeep ? cloneArrayBuffer(typedArray.buffer) : typedArray.buffer;
    return new typedArray.constructor(buffer, typedArray.byteOffset, typedArray.length);
  }

  /**
   * Compares values to sort them in ascending order.
   *
   * @private
   * @param {*} value The value to compare.
   * @param {*} other The other value to compare.
   * @returns {number} Returns the sort order indicator for `value`.
   */
  function compareAscending(value, other) {
    if (value !== other) {
      var valIsDefined = value !== undefined,
          valIsNull = value === null,
          valIsReflexive = value === value,
          valIsSymbol = isSymbol(value);

      var othIsDefined = other !== undefined,
          othIsNull = other === null,
          othIsReflexive = other === other,
          othIsSymbol = isSymbol(other);

      if ((!othIsNull && !othIsSymbol && !valIsSymbol && value > other) ||
          (valIsSymbol && othIsDefined && othIsReflexive && !othIsNull && !othIsSymbol) ||
          (valIsNull && othIsDefined && othIsReflexive) ||
          (!valIsDefined && othIsReflexive) ||
          !valIsReflexive) {
        return 1;
      }
      if ((!valIsNull && !valIsSymbol && !othIsSymbol && value < other) ||
          (othIsSymbol && valIsDefined && valIsReflexive && !valIsNull && !valIsSymbol) ||
          (othIsNull && valIsDefined && valIsReflexive) ||
          (!othIsDefined && valIsReflexive) ||
          !othIsReflexive) {
        return -1;
      }
    }
    return 0;
  }

  /**
   * Used by `_.orderBy` to compare multiple properties of a value to another
   * and stable sort them.
   *
   * If `orders` is unspecified, all values are sorted in ascending order. Otherwise,
   * specify an order of "desc" for descending or "asc" for ascending sort order
   * of corresponding values.
   *
   * @private
   * @param {Object} object The object to compare.
   * @param {Object} other The other object to compare.
   * @param {boolean[]|string[]} orders The order to sort by for each property.
   * @returns {number} Returns the sort order indicator for `object`.
   */
  function compareMultiple(object, other, orders) {
    var index = -1,
        objCriteria = object.criteria,
        othCriteria = other.criteria,
        length = objCriteria.length,
        ordersLength = orders.length;

    while (++index < length) {
      var result = compareAscending(objCriteria[index], othCriteria[index]);
      if (result) {
        if (index >= ordersLength) {
          return result;
        }
        var order = orders[index];
        return result * (order == 'desc' ? -1 : 1);
      }
    }
    // Fixes an `Array#sort` bug in the JS engine embedded in Adobe applications
    // that causes it, under certain circumstances, to provide the same value for
    // `object` and `other`. See https://github.com/jashkenas/underscore/pull/1247
    // for more details.
    //
    // This also ensures a stable sort in V8 and other engines.
    // See https://bugs.chromium.org/p/v8/issues/detail?id=90 for more details.
    return object.index - other.index;
  }

  /**
   * Creates an array that is the composition of partially applied arguments,
   * placeholders, and provided arguments into a single array of arguments.
   *
   * @private
   * @param {Array} args The provided arguments.
   * @param {Array} partials The arguments to prepend to those provided.
   * @param {Array} holders The `partials` placeholder indexes.
   * @params {boolean} [isCurried] Specify composing for a curried function.
   * @returns {Array} Returns the new array of composed arguments.
   */
  function composeArgs(args, partials, holders, isCurried) {
    var argsIndex = -1,
        argsLength = args.length,
        holdersLength = holders.length,
        leftIndex = -1,
        leftLength = partials.length,
        rangeLength = nativeMax(argsLength - holdersLength, 0),
        result = Array(leftLength + rangeLength),
        isUncurried = !isCurried;

    while (++leftIndex < leftLength) {
      result[leftIndex] = partials[leftIndex];
    }
    while (++argsIndex < holdersLength) {
      if (isUncurried || argsIndex < argsLength) {
        result[holders[argsIndex]] = args[argsIndex];
      }
    }
    while (rangeLength--) {
      result[leftIndex++] = args[argsIndex++];
    }
    return result;
  }

  /**
   * This function is like `composeArgs` except that the arguments composition
   * is tailored for `_.partialRight`.
   *
   * @private
   * @param {Array} args The provided arguments.
   * @param {Array} partials The arguments to append to those provided.
   * @param {Array} holders The `partials` placeholder indexes.
   * @params {boolean} [isCurried] Specify composing for a curried function.
   * @returns {Array} Returns the new array of composed arguments.
   */
  function composeArgsRight(args, partials, holders, isCurried) {
    var argsIndex = -1,
        argsLength = args.length,
        holdersIndex = -1,
        holdersLength = holders.length,
        rightIndex = -1,
        rightLength = partials.length,
        rangeLength = nativeMax(argsLength - holdersLength, 0),
        result = Array(rangeLength + rightLength),
        isUncurried = !isCurried;

    while (++argsIndex < rangeLength) {
      result[argsIndex] = args[argsIndex];
    }
    var offset = argsIndex;
    while (++rightIndex < rightLength) {
      result[offset + rightIndex] = partials[rightIndex];
    }
    while (++holdersIndex < holdersLength) {
      if (isUncurried || argsIndex < argsLength) {
        result[offset + holders[holdersIndex]] = args[argsIndex++];
      }
    }
    return result;
  }

  /**
   * Copies the values of `source` to `array`.
   *
   * @private
   * @param {Array} source The array to copy values from.
   * @param {Array} [array=[]] The array to copy values to.
   * @returns {Array} Returns `array`.
   */
  function copyArray(source, array) {
    var index = -1,
        length = source.length;

    array || (array = Array(length));
    while (++index < length) {
      array[index] = source[index];
    }
    return array;
  }

  /**
   * Copies properties of `source` to `object`.
   *
   * @private
   * @param {Object} source The object to copy properties from.
   * @param {Array} props The property identifiers to copy.
   * @param {Object} [object={}] The object to copy properties to.
   * @param {Function} [customizer] The function to customize copied values.
   * @returns {Object} Returns `object`.
   */
  function copyObject(source, props, object, customizer) {
    var isNew = !object;
    object || (object = {});

    var index = -1,
        length = props.length;

    while (++index < length) {
      var key = props[index];

      var newValue = customizer
        ? customizer(object[key], source[key], key, object, source)
        : undefined;

      if (newValue === undefined) {
        newValue = source[key];
      }
      if (isNew) {
        baseAssignValue(object, key, newValue);
      } else {
        assignValue(object, key, newValue);
      }
    }
    return object;
  }

  /**
   * Copies own symbols of `source` to `object`.
   *
   * @private
   * @param {Object} source The object to copy symbols from.
   * @param {Object} [object={}] The object to copy symbols to.
   * @returns {Object} Returns `object`.
   */
  function copySymbols(source, object) {
    return copyObject(source, getSymbols(source), object);
  }

  /**
   * Copies own and inherited symbols of `source` to `object`.
   *
   * @private
   * @param {Object} source The object to copy symbols from.
   * @param {Object} [object={}] The object to copy symbols to.
   * @returns {Object} Returns `object`.
   */
  function copySymbolsIn(source, object) {
    return copyObject(source, getSymbolsIn(source), object);
  }

  /**
   * Creates a function like `_.groupBy`.
   *
   * @private
   * @param {Function} setter The function to set accumulator values.
   * @param {Function} [initializer] The accumulator object initializer.
   * @returns {Function} Returns the new aggregator function.
   */
  function createAggregator(setter, initializer) {
    return function(collection, iteratee) {
      var func = isArray(collection) ? arrayAggregator : baseAggregator,
          accumulator = initializer ? initializer() : {};

      return func(collection, setter, getIteratee(iteratee, 2), accumulator);
    };
  }

  /**
   * Creates a function like `_.assign`.
   *
   * @private
   * @param {Function} assigner The function to assign values.
   * @returns {Function} Returns the new assigner function.
   */
  function createAssigner(assigner) {
    return baseRest(function(object, sources) {
      var index = -1,
          length = sources.length,
          customizer = length > 1 ? sources[length - 1] : undefined,
          guard = length > 2 ? sources[2] : undefined;

      customizer = (assigner.length > 3 && typeof customizer == 'function')
        ? (length--, customizer)
        : undefined;

      if (guard && isIterateeCall(sources[0], sources[1], guard)) {
        customizer = length < 3 ? undefined : customizer;
        length = 1;
      }
      object = Object(object);
      while (++index < length) {
        var source = sources[index];
        if (source) {
          assigner(object, source, index, customizer);
        }
      }
      return object;
    });
  }

  /**
   * Creates a `baseEach` or `baseEachRight` function.
   *
   * @private
   * @param {Function} eachFunc The function to iterate over a collection.
   * @param {boolean} [fromRight] Specify iterating from right to left.
   * @returns {Function} Returns the new base function.
   */
  function createBaseEach(eachFunc, fromRight) {
    return function(collection, iteratee) {
      if (collection == null) {
        return collection;
      }
      if (!isArrayLike(collection)) {
        return eachFunc(collection, iteratee);
      }
      var length = collection.length,
          index = fromRight ? length : -1,
          iterable = Object(collection);

      while ((fromRight ? index-- : ++index < length)) {
        if (iteratee(iterable[index], index, iterable) === false) {
          break;
        }
      }
      return collection;
    };
  }

  /**
   * Creates a base function for methods like `_.forIn` and `_.forOwn`.
   *
   * @private
   * @param {boolean} [fromRight] Specify iterating from right to left.
   * @returns {Function} Returns the new base function.
   */
  function createBaseFor(fromRight) {
    return function(object, iteratee, keysFunc) {
      var index = -1,
          iterable = Object(object),
          props = keysFunc(object),
          length = props.length;

      while (length--) {
        var key = props[fromRight ? length : ++index];
        if (iteratee(iterable[key], key, iterable) === false) {
          break;
        }
      }
      return object;
    };
  }

  /**
   * Creates a function that produces an instance of `Ctor` regardless of
   * whether it was invoked as part of a `new` expression or by `call` or `apply`.
   *
   * @private
   * @param {Function} Ctor The constructor to wrap.
   * @returns {Function} Returns the new wrapped function.
   */
  function createCtor(Ctor) {
    return function() {
      // Use a `switch` statement to work with class constructors. See
      // http://ecma-international.org/ecma-262/7.0/#sec-ecmascript-function-objects-call-thisargument-argumentslist
      // for more details.
      var args = arguments;
      switch (args.length) {
        case 0: return new Ctor;
        case 1: return new Ctor(args[0]);
        case 2: return new Ctor(args[0], args[1]);
        case 3: return new Ctor(args[0], args[1], args[2]);
        case 4: return new Ctor(args[0], args[1], args[2], args[3]);
        case 5: return new Ctor(args[0], args[1], args[2], args[3], args[4]);
        case 6: return new Ctor(args[0], args[1], args[2], args[3], args[4], args[5]);
        case 7: return new Ctor(args[0], args[1], args[2], args[3], args[4], args[5], args[6]);
      }
      var thisBinding = baseCreate(Ctor.prototype),
          result = Ctor.apply(thisBinding, args);

      // Mimic the constructor's `return` behavior.
      // See https://es5.github.io/#x13.2.2 for more details.
      return isObject(result) ? result : thisBinding;
    };
  }

  /**
   * Creates a `_.find` or `_.findLast` function.
   *
   * @private
   * @param {Function} findIndexFunc The function to find the collection index.
   * @returns {Function} Returns the new find function.
   */
  function createFind(findIndexFunc) {
    return function(collection, predicate, fromIndex) {
      var iterable = Object(collection);
      if (!isArrayLike(collection)) {
        var iteratee = getIteratee(predicate, 3);
        collection = keys(collection);
        predicate = function(key) { return iteratee(iterable[key], key, iterable); };
      }
      var index = findIndexFunc(collection, predicate, fromIndex);
      return index > -1 ? iterable[iteratee ? collection[index] : index] : undefined;
    };
  }

  /**
   * Creates a function that wraps `func` to invoke it with optional `this`
   * binding of `thisArg`, partial application, and currying.
   *
   * @private
   * @param {Function|string} func The function or method name to wrap.
   * @param {number} bitmask The bitmask flags. See `createWrap` for more details.
   * @param {*} [thisArg] The `this` binding of `func`.
   * @param {Array} [partials] The arguments to prepend to those provided to
   *  the new function.
   * @param {Array} [holders] The `partials` placeholder indexes.
   * @param {Array} [partialsRight] The arguments to append to those provided
   *  to the new function.
   * @param {Array} [holdersRight] The `partialsRight` placeholder indexes.
   * @param {Array} [argPos] The argument positions of the new function.
   * @param {number} [ary] The arity cap of `func`.
   * @param {number} [arity] The arity of `func`.
   * @returns {Function} Returns the new wrapped function.
   */
  function createHybrid(func, bitmask, thisArg, partials, holders, partialsRight, holdersRight, argPos, ary, arity) {
    var isAry = bitmask & WRAP_ARY_FLAG,
        isBind = bitmask & WRAP_BIND_FLAG,
        isBindKey = bitmask & WRAP_BIND_KEY_FLAG,
        isCurried = bitmask & (WRAP_CURRY_FLAG | WRAP_CURRY_RIGHT_FLAG),
        isFlip = bitmask & WRAP_FLIP_FLAG,
        Ctor = isBindKey ? undefined : createCtor(func);

    function wrapper() {
      var length = arguments.length,
          args = Array(length),
          index = length;

      while (index--) {
        args[index] = arguments[index];
      }
      if (isCurried) {
        var placeholder = getHolder(wrapper),
            holdersCount = countHolders(args, placeholder);
      }
      if (partials) {
        args = composeArgs(args, partials, holders, isCurried);
      }
      if (partialsRight) {
        args = composeArgsRight(args, partialsRight, holdersRight, isCurried);
      }
      length -= holdersCount;
      if (isCurried && length < arity) {
        var newHolders = replaceHolders(args, placeholder);
        return createRecurry(
          func, bitmask, createHybrid, wrapper.placeholder, thisArg,
          args, newHolders, argPos, ary, arity - length
        );
      }
      var thisBinding = isBind ? thisArg : this,
          fn = isBindKey ? thisBinding[func] : func;

      length = args.length;
      if (argPos) {
        args = reorder(args, argPos);
      } else if (isFlip && length > 1) {
        args.reverse();
      }
      if (isAry && ary < length) {
        args.length = ary;
      }
      if (this && this !== root && this instanceof wrapper) {
        fn = Ctor || createCtor(fn);
      }
      return fn.apply(thisBinding, args);
    }
    return wrapper;
  }

  /**
   * Creates a `_.range` or `_.rangeRight` function.
   *
   * @private
   * @param {boolean} [fromRight] Specify iterating from right to left.
   * @returns {Function} Returns the new range function.
   */
  function createRange(fromRight) {
    return function(start, end, step) {
      if (step && typeof step != 'number' && isIterateeCall(start, end, step)) {
        end = step = undefined;
      }
      // Ensure the sign of `-0` is preserved.
      start = toFinite(start);
      if (end === undefined) {
        end = start;
        start = 0;
      } else {
        end = toFinite(end);
      }
      step = step === undefined ? (start < end ? 1 : -1) : toFinite(step);
      return baseRange(start, end, step, fromRight);
    };
  }

  /**
   * Creates a function that wraps `func` to continue currying.
   *
   * @private
   * @param {Function} func The function to wrap.
   * @param {number} bitmask The bitmask flags. See `createWrap` for more details.
   * @param {Function} wrapFunc The function to create the `func` wrapper.
   * @param {*} placeholder The placeholder value.
   * @param {*} [thisArg] The `this` binding of `func`.
   * @param {Array} [partials] The arguments to prepend to those provided to
   *  the new function.
   * @param {Array} [holders] The `partials` placeholder indexes.
   * @param {Array} [argPos] The argument positions of the new function.
   * @param {number} [ary] The arity cap of `func`.
   * @param {number} [arity] The arity of `func`.
   * @returns {Function} Returns the new wrapped function.
   */
  function createRecurry(func, bitmask, wrapFunc, placeholder, thisArg, partials, holders, argPos, ary, arity) {
    var isCurry = bitmask & WRAP_CURRY_FLAG,
        newHolders = isCurry ? holders : undefined,
        newHoldersRight = isCurry ? undefined : holders,
        newPartials = isCurry ? partials : undefined,
        newPartialsRight = isCurry ? undefined : partials;

    bitmask |= (isCurry ? WRAP_PARTIAL_FLAG : WRAP_PARTIAL_RIGHT_FLAG);
    bitmask &= ~(isCurry ? WRAP_PARTIAL_RIGHT_FLAG : WRAP_PARTIAL_FLAG);

    if (!(bitmask & WRAP_CURRY_BOUND_FLAG)) {
      bitmask &= ~(WRAP_BIND_FLAG | WRAP_BIND_KEY_FLAG);
    }
    var newData = [
      func, bitmask, thisArg, newPartials, newHolders, newPartialsRight,
      newHoldersRight, argPos, ary, arity
    ];

    var result = wrapFunc.apply(undefined, newData);
    if (isLaziable(func)) {
      setData(result, newData);
    }
    result.placeholder = placeholder;
    return setWrapToString(result, func, bitmask);
  }

  /**
   * Creates a set object of `values`.
   *
   * @private
   * @param {Array} values The values to add to the set.
   * @returns {Object} Returns the new set.
   */
  var createSet = !(Set && (1 / setToArray(new Set([,-0]))[1]) == INFINITY) ? noop : function(values) {
    return new Set(values);
  };

  /**
   * Used by `_.omit` to customize its `_.cloneDeep` use to only clone plain
   * objects.
   *
   * @private
   * @param {*} value The value to inspect.
   * @param {string} key The key of the property to inspect.
   * @returns {*} Returns the uncloned value or `undefined` to defer cloning to `_.cloneDeep`.
   */
  function customOmitClone(value) {
    return isPlainObject(value) ? undefined : value;
  }

  /**
   * A specialized version of `baseIsEqualDeep` for arrays with support for
   * partial deep comparisons.
   *
   * @private
   * @param {Array} array The array to compare.
   * @param {Array} other The other array to compare.
   * @param {number} bitmask The bitmask flags. See `baseIsEqual` for more details.
   * @param {Function} customizer The function to customize comparisons.
   * @param {Function} equalFunc The function to determine equivalents of values.
   * @param {Object} stack Tracks traversed `array` and `other` objects.
   * @returns {boolean} Returns `true` if the arrays are equivalent, else `false`.
   */
  function equalArrays(array, other, bitmask, customizer, equalFunc, stack) {
    var isPartial = bitmask & COMPARE_PARTIAL_FLAG,
        arrLength = array.length,
        othLength = other.length;

    if (arrLength != othLength && !(isPartial && othLength > arrLength)) {
      return false;
    }
    // Assume cyclic values are equal.
    var stacked = stack.get(array);
    if (stacked && stack.get(other)) {
      return stacked == other;
    }
    var index = -1,
        result = true,
        seen = (bitmask & COMPARE_UNORDERED_FLAG) ? new SetCache : undefined;

    stack.set(array, other);
    stack.set(other, array);

    // Ignore non-index properties.
    while (++index < arrLength) {
      var arrValue = array[index],
          othValue = other[index];

      if (customizer) {
        var compared = isPartial
          ? customizer(othValue, arrValue, index, other, array, stack)
          : customizer(arrValue, othValue, index, array, other, stack);
      }
      if (compared !== undefined) {
        if (compared) {
          continue;
        }
        result = false;
        break;
      }
      // Recursively compare arrays (susceptible to call stack limits).
      if (seen) {
        if (!arraySome(other, function(othValue, othIndex) {
              if (!cacheHas(seen, othIndex) &&
                  (arrValue === othValue || equalFunc(arrValue, othValue, bitmask, customizer, stack))) {
                return seen.push(othIndex);
              }
            })) {
          result = false;
          break;
        }
      } else if (!(
            arrValue === othValue ||
              equalFunc(arrValue, othValue, bitmask, customizer, stack)
          )) {
        result = false;
        break;
      }
    }
    stack['delete'](array);
    stack['delete'](other);
    return result;
  }

  /**
   * A specialized version of `baseIsEqualDeep` for comparing objects of
   * the same `toStringTag`.
   *
   * **Note:** This function only supports comparing values with tags of
   * `Boolean`, `Date`, `Error`, `Number`, `RegExp`, or `String`.
   *
   * @private
   * @param {Object} object The object to compare.
   * @param {Object} other The other object to compare.
   * @param {string} tag The `toStringTag` of the objects to compare.
   * @param {number} bitmask The bitmask flags. See `baseIsEqual` for more details.
   * @param {Function} customizer The function to customize comparisons.
   * @param {Function} equalFunc The function to determine equivalents of values.
   * @param {Object} stack Tracks traversed `object` and `other` objects.
   * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
   */
  function equalByTag(object, other, tag, bitmask, customizer, equalFunc, stack) {
    switch (tag) {
      case dataViewTag:
        if ((object.byteLength != other.byteLength) ||
            (object.byteOffset != other.byteOffset)) {
          return false;
        }
        object = object.buffer;
        other = other.buffer;

      case arrayBufferTag:
        if ((object.byteLength != other.byteLength) ||
            !equalFunc(new Uint8Array(object), new Uint8Array(other))) {
          return false;
        }
        return true;

      case boolTag:
      case dateTag:
      case numberTag:
        // Coerce booleans to `1` or `0` and dates to milliseconds.
        // Invalid dates are coerced to `NaN`.
        return eq(+object, +other);

      case errorTag:
        return object.name == other.name && object.message == other.message;

      case regexpTag:
      case stringTag:
        // Coerce regexes to strings and treat strings, primitives and objects,
        // as equal. See http://www.ecma-international.org/ecma-262/7.0/#sec-regexp.prototype.tostring
        // for more details.
        return object == (other + '');

      case mapTag:
        var convert = mapToArray;

      case setTag:
        var isPartial = bitmask & COMPARE_PARTIAL_FLAG;
        convert || (convert = setToArray);

        if (object.size != other.size && !isPartial) {
          return false;
        }
        // Assume cyclic values are equal.
        var stacked = stack.get(object);
        if (stacked) {
          return stacked == other;
        }
        bitmask |= COMPARE_UNORDERED_FLAG;

        // Recursively compare objects (susceptible to call stack limits).
        stack.set(object, other);
        var result = equalArrays(convert(object), convert(other), bitmask, customizer, equalFunc, stack);
        stack['delete'](object);
        return result;

      case symbolTag:
        if (symbolValueOf) {
          return symbolValueOf.call(object) == symbolValueOf.call(other);
        }
    }
    return false;
  }

  /**
   * A specialized version of `baseIsEqualDeep` for objects with support for
   * partial deep comparisons.
   *
   * @private
   * @param {Object} object The object to compare.
   * @param {Object} other The other object to compare.
   * @param {number} bitmask The bitmask flags. See `baseIsEqual` for more details.
   * @param {Function} customizer The function to customize comparisons.
   * @param {Function} equalFunc The function to determine equivalents of values.
   * @param {Object} stack Tracks traversed `object` and `other` objects.
   * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
   */
  function equalObjects(object, other, bitmask, customizer, equalFunc, stack) {
    var isPartial = bitmask & COMPARE_PARTIAL_FLAG,
        objProps = getAllKeys(object),
        objLength = objProps.length,
        othProps = getAllKeys(other),
        othLength = othProps.length;

    if (objLength != othLength && !isPartial) {
      return false;
    }
    var index = objLength;
    while (index--) {
      var key = objProps[index];
      if (!(isPartial ? key in other : hasOwnProperty.call(other, key))) {
        return false;
      }
    }
    // Assume cyclic values are equal.
    var stacked = stack.get(object);
    if (stacked && stack.get(other)) {
      return stacked == other;
    }
    var result = true;
    stack.set(object, other);
    stack.set(other, object);

    var skipCtor = isPartial;
    while (++index < objLength) {
      key = objProps[index];
      var objValue = object[key],
          othValue = other[key];

      if (customizer) {
        var compared = isPartial
          ? customizer(othValue, objValue, key, other, object, stack)
          : customizer(objValue, othValue, key, object, other, stack);
      }
      // Recursively compare objects (susceptible to call stack limits).
      if (!(compared === undefined
            ? (objValue === othValue || equalFunc(objValue, othValue, bitmask, customizer, stack))
            : compared
          )) {
        result = false;
        break;
      }
      skipCtor || (skipCtor = key == 'constructor');
    }
    if (result && !skipCtor) {
      var objCtor = object.constructor,
          othCtor = other.constructor;

      // Non `Object` object instances with different constructors are not equal.
      if (objCtor != othCtor &&
          ('constructor' in object && 'constructor' in other) &&
          !(typeof objCtor == 'function' && objCtor instanceof objCtor &&
            typeof othCtor == 'function' && othCtor instanceof othCtor)) {
        result = false;
      }
    }
    stack['delete'](object);
    stack['delete'](other);
    return result;
  }

  /**
   * A specialized version of `baseRest` which flattens the rest array.
   *
   * @private
   * @param {Function} func The function to apply a rest parameter to.
   * @returns {Function} Returns the new function.
   */
  function flatRest(func) {
    return setToString(overRest(func, undefined, flatten), func + '');
  }

  /**
   * Creates an array of own enumerable property names and symbols of `object`.
   *
   * @private
   * @param {Object} object The object to query.
   * @returns {Array} Returns the array of property names and symbols.
   */
  function getAllKeys(object) {
    return baseGetAllKeys(object, keys, getSymbols);
  }

  /**
   * Creates an array of own and inherited enumerable property names and
   * symbols of `object`.
   *
   * @private
   * @param {Object} object The object to query.
   * @returns {Array} Returns the array of property names and symbols.
   */
  function getAllKeysIn(object) {
    return baseGetAllKeys(object, keysIn, getSymbolsIn);
  }

  /**
   * Gets metadata for `func`.
   *
   * @private
   * @param {Function} func The function to query.
   * @returns {*} Returns the metadata for `func`.
   */
  var getData = !metaMap ? noop : function(func) {
    return metaMap.get(func);
  };

  /**
   * Gets the name of `func`.
   *
   * @private
   * @param {Function} func The function to query.
   * @returns {string} Returns the function name.
   */
  function getFuncName(func) {
    var result = (func.name + ''),
        array = realNames[result],
        length = hasOwnProperty.call(realNames, result) ? array.length : 0;

    while (length--) {
      var data = array[length],
          otherFunc = data.func;
      if (otherFunc == null || otherFunc == func) {
        return data.name;
      }
    }
    return result;
  }

  /**
   * Gets the argument placeholder value for `func`.
   *
   * @private
   * @param {Function} func The function to inspect.
   * @returns {*} Returns the placeholder value.
   */
  function getHolder(func) {
    var object = hasOwnProperty.call(lodash, 'placeholder') ? lodash : func;
    return object.placeholder;
  }

  /**
   * Gets the appropriate "iteratee" function. If `_.iteratee` is customized,
   * this function returns the custom method, otherwise it returns `baseIteratee`.
   * If arguments are provided, the chosen function is invoked with them and
   * its result is returned.
   *
   * @private
   * @param {*} [value] The value to convert to an iteratee.
   * @param {number} [arity] The arity of the created iteratee.
   * @returns {Function} Returns the chosen function or its result.
   */
  function getIteratee() {
    var result = lodash.iteratee || iteratee;
    result = result === iteratee ? baseIteratee : result;
    return arguments.length ? result(arguments[0], arguments[1]) : result;
  }

  /**
   * Gets the data for `map`.
   *
   * @private
   * @param {Object} map The map to query.
   * @param {string} key The reference key.
   * @returns {*} Returns the map data.
   */
  function getMapData(map, key) {
    var data = map.__data__;
    return isKeyable(key)
      ? data[typeof key == 'string' ? 'string' : 'hash']
      : data.map;
  }

  /**
   * Gets the property names, values, and compare flags of `object`.
   *
   * @private
   * @param {Object} object The object to query.
   * @returns {Array} Returns the match data of `object`.
   */
  function getMatchData(object) {
    var result = keys(object),
        length = result.length;

    while (length--) {
      var key = result[length],
          value = object[key];

      result[length] = [key, value, isStrictComparable(value)];
    }
    return result;
  }

  /**
   * Gets the native function at `key` of `object`.
   *
   * @private
   * @param {Object} object The object to query.
   * @param {string} key The key of the method to get.
   * @returns {*} Returns the function if it's native, else `undefined`.
   */
  function getNative(object, key) {
    var value = getValue(object, key);
    return baseIsNative(value) ? value : undefined;
  }

  /**
   * A specialized version of `baseGetTag` which ignores `Symbol.toStringTag` values.
   *
   * @private
   * @param {*} value The value to query.
   * @returns {string} Returns the raw `toStringTag`.
   */
  function getRawTag(value) {
    var isOwn = hasOwnProperty.call(value, symToStringTag),
        tag = value[symToStringTag];

    try {
      value[symToStringTag] = undefined;
      var unmasked = true;
    } catch (e) {}

    var result = nativeObjectToString.call(value);
    if (unmasked) {
      if (isOwn) {
        value[symToStringTag] = tag;
      } else {
        delete value[symToStringTag];
      }
    }
    return result;
  }

  /**
   * Creates an array of the own enumerable symbols of `object`.
   *
   * @private
   * @param {Object} object The object to query.
   * @returns {Array} Returns the array of symbols.
   */
  var getSymbols = !nativeGetSymbols ? stubArray : function(object) {
    if (object == null) {
      return [];
    }
    object = Object(object);
    return arrayFilter(nativeGetSymbols(object), function(symbol) {
      return propertyIsEnumerable.call(object, symbol);
    });
  };

  /**
   * Creates an array of the own and inherited enumerable symbols of `object`.
   *
   * @private
   * @param {Object} object The object to query.
   * @returns {Array} Returns the array of symbols.
   */
  var getSymbolsIn = !nativeGetSymbols ? stubArray : function(object) {
    var result = [];
    while (object) {
      arrayPush(result, getSymbols(object));
      object = getPrototype(object);
    }
    return result;
  };

  /**
   * Gets the `toStringTag` of `value`.
   *
   * @private
   * @param {*} value The value to query.
   * @returns {string} Returns the `toStringTag`.
   */
  var getTag = baseGetTag;

  // Fallback for data views, maps, sets, and weak maps in IE 11 and promises in Node.js < 6.
  if ((DataView && getTag(new DataView(new ArrayBuffer(1))) != dataViewTag) ||
      (Map && getTag(new Map) != mapTag) ||
      (Promise && getTag(Promise.resolve()) != promiseTag) ||
      (Set && getTag(new Set) != setTag) ||
      (WeakMap && getTag(new WeakMap) != weakMapTag)) {
    getTag = function(value) {
      var result = baseGetTag(value),
          Ctor = result == objectTag ? value.constructor : undefined,
          ctorString = Ctor ? toSource(Ctor) : '';

      if (ctorString) {
        switch (ctorString) {
          case dataViewCtorString: return dataViewTag;
          case mapCtorString: return mapTag;
          case promiseCtorString: return promiseTag;
          case setCtorString: return setTag;
          case weakMapCtorString: return weakMapTag;
        }
      }
      return result;
    };
  }

  /**
   * Gets the view, applying any `transforms` to the `start` and `end` positions.
   *
   * @private
   * @param {number} start The start of the view.
   * @param {number} end The end of the view.
   * @param {Array} transforms The transformations to apply to the view.
   * @returns {Object} Returns an object containing the `start` and `end`
   *  positions of the view.
   */
  function getView(start, end, transforms) {
    var index = -1,
        length = transforms.length;

    while (++index < length) {
      var data = transforms[index],
          size = data.size;

      switch (data.type) {
        case 'drop':      start += size; break;
        case 'dropRight': end -= size; break;
        case 'take':      end = nativeMin(end, start + size); break;
        case 'takeRight': start = nativeMax(start, end - size); break;
      }
    }
    return { 'start': start, 'end': end };
  }

  /**
   * Extracts wrapper details from the `source` body comment.
   *
   * @private
   * @param {string} source The source to inspect.
   * @returns {Array} Returns the wrapper details.
   */
  function getWrapDetails(source) {
    var match = source.match(reWrapDetails);
    return match ? match[1].split(reSplitDetails) : [];
  }

  /**
   * Checks if `path` exists on `object`.
   *
   * @private
   * @param {Object} object The object to query.
   * @param {Array|string} path The path to check.
   * @param {Function} hasFunc The function to check properties.
   * @returns {boolean} Returns `true` if `path` exists, else `false`.
   */
  function hasPath(object, path, hasFunc) {
    path = castPath(path, object);

    var index = -1,
        length = path.length,
        result = false;

    while (++index < length) {
      var key = toKey(path[index]);
      if (!(result = object != null && hasFunc(object, key))) {
        break;
      }
      object = object[key];
    }
    if (result || ++index != length) {
      return result;
    }
    length = object == null ? 0 : object.length;
    return !!length && isLength(length) && isIndex(key, length) &&
      (isArray(object) || isArguments(object));
  }

  /**
   * Initializes an array clone.
   *
   * @private
   * @param {Array} array The array to clone.
   * @returns {Array} Returns the initialized clone.
   */
  function initCloneArray(array) {
    var length = array.length,
        result = new array.constructor(length);

    // Add properties assigned by `RegExp#exec`.
    if (length && typeof array[0] == 'string' && hasOwnProperty.call(array, 'index')) {
      result.index = array.index;
      result.input = array.input;
    }
    return result;
  }

  /**
   * Initializes an object clone.
   *
   * @private
   * @param {Object} object The object to clone.
   * @returns {Object} Returns the initialized clone.
   */
  function initCloneObject(object) {
    return (typeof object.constructor == 'function' && !isPrototype(object))
      ? baseCreate(getPrototype(object))
      : {};
  }

  /**
   * Initializes an object clone based on its `toStringTag`.
   *
   * **Note:** This function only supports cloning values with tags of
   * `Boolean`, `Date`, `Error`, `Map`, `Number`, `RegExp`, `Set`, or `String`.
   *
   * @private
   * @param {Object} object The object to clone.
   * @param {string} tag The `toStringTag` of the object to clone.
   * @param {boolean} [isDeep] Specify a deep clone.
   * @returns {Object} Returns the initialized clone.
   */
  function initCloneByTag(object, tag, isDeep) {
    var Ctor = object.constructor;
    switch (tag) {
      case arrayBufferTag:
        return cloneArrayBuffer(object);

      case boolTag:
      case dateTag:
        return new Ctor(+object);

      case dataViewTag:
        return cloneDataView(object, isDeep);

      case float32Tag: case float64Tag:
      case int8Tag: case int16Tag: case int32Tag:
      case uint8Tag: case uint8ClampedTag: case uint16Tag: case uint32Tag:
        return cloneTypedArray(object, isDeep);

      case mapTag:
        return new Ctor;

      case numberTag:
      case stringTag:
        return new Ctor(object);

      case regexpTag:
        return cloneRegExp(object);

      case setTag:
        return new Ctor;

      case symbolTag:
        return cloneSymbol(object);
    }
  }

  /**
   * Inserts wrapper `details` in a comment at the top of the `source` body.
   *
   * @private
   * @param {string} source The source to modify.
   * @returns {Array} details The details to insert.
   * @returns {string} Returns the modified source.
   */
  function insertWrapDetails(source, details) {
    var length = details.length;
    if (!length) {
      return source;
    }
    var lastIndex = length - 1;
    details[lastIndex] = (length > 1 ? '& ' : '') + details[lastIndex];
    details = details.join(length > 2 ? ', ' : ' ');
    return source.replace(reWrapComment, '{\n/* [wrapped with ' + details + '] */\n');
  }

  /**
   * Checks if `value` is a flattenable `arguments` object or array.
   *
   * @private
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is flattenable, else `false`.
   */
  function isFlattenable(value) {
    return isArray(value) || isArguments(value) ||
      !!(spreadableSymbol && value && value[spreadableSymbol]);
  }

  /**
   * Checks if `value` is a valid array-like index.
   *
   * @private
   * @param {*} value The value to check.
   * @param {number} [length=MAX_SAFE_INTEGER] The upper bounds of a valid index.
   * @returns {boolean} Returns `true` if `value` is a valid index, else `false`.
   */
  function isIndex(value, length) {
    var type = typeof value;
    length = length == null ? MAX_SAFE_INTEGER : length;

    return !!length &&
      (type == 'number' ||
        (type != 'symbol' && reIsUint.test(value))) &&
          (value > -1 && value % 1 == 0 && value < length);
  }

  /**
   * Checks if the given arguments are from an iteratee call.
   *
   * @private
   * @param {*} value The potential iteratee value argument.
   * @param {*} index The potential iteratee index or key argument.
   * @param {*} object The potential iteratee object argument.
   * @returns {boolean} Returns `true` if the arguments are from an iteratee call,
   *  else `false`.
   */
  function isIterateeCall(value, index, object) {
    if (!isObject(object)) {
      return false;
    }
    var type = typeof index;
    if (type == 'number'
          ? (isArrayLike(object) && isIndex(index, object.length))
          : (type == 'string' && index in object)
        ) {
      return eq(object[index], value);
    }
    return false;
  }

  /**
   * Checks if `value` is a property name and not a property path.
   *
   * @private
   * @param {*} value The value to check.
   * @param {Object} [object] The object to query keys on.
   * @returns {boolean} Returns `true` if `value` is a property name, else `false`.
   */
  function isKey(value, object) {
    if (isArray(value)) {
      return false;
    }
    var type = typeof value;
    if (type == 'number' || type == 'symbol' || type == 'boolean' ||
        value == null || isSymbol(value)) {
      return true;
    }
    return reIsPlainProp.test(value) || !reIsDeepProp.test(value) ||
      (object != null && value in Object(object));
  }

  /**
   * Checks if `value` is suitable for use as unique object key.
   *
   * @private
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is suitable, else `false`.
   */
  function isKeyable(value) {
    var type = typeof value;
    return (type == 'string' || type == 'number' || type == 'symbol' || type == 'boolean')
      ? (value !== '__proto__')
      : (value === null);
  }

  /**
   * Checks if `func` has a lazy counterpart.
   *
   * @private
   * @param {Function} func The function to check.
   * @returns {boolean} Returns `true` if `func` has a lazy counterpart,
   *  else `false`.
   */
  function isLaziable(func) {
    var funcName = getFuncName(func),
        other = lodash[funcName];

    if (typeof other != 'function' || !(funcName in LazyWrapper.prototype)) {
      return false;
    }
    if (func === other) {
      return true;
    }
    var data = getData(other);
    return !!data && func === data[0];
  }

  /**
   * Checks if `func` has its source masked.
   *
   * @private
   * @param {Function} func The function to check.
   * @returns {boolean} Returns `true` if `func` is masked, else `false`.
   */
  function isMasked(func) {
    return !!maskSrcKey && (maskSrcKey in func);
  }

  /**
   * Checks if `value` is likely a prototype object.
   *
   * @private
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is a prototype, else `false`.
   */
  function isPrototype(value) {
    var Ctor = value && value.constructor,
        proto = (typeof Ctor == 'function' && Ctor.prototype) || objectProto;

    return value === proto;
  }

  /**
   * Checks if `value` is suitable for strict equality comparisons, i.e. `===`.
   *
   * @private
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` if suitable for strict
   *  equality comparisons, else `false`.
   */
  function isStrictComparable(value) {
    return value === value && !isObject(value);
  }

  /**
   * A specialized version of `matchesProperty` for source values suitable
   * for strict equality comparisons, i.e. `===`.
   *
   * @private
   * @param {string} key The key of the property to get.
   * @param {*} srcValue The value to match.
   * @returns {Function} Returns the new spec function.
   */
  function matchesStrictComparable(key, srcValue) {
    return function(object) {
      if (object == null) {
        return false;
      }
      return object[key] === srcValue &&
        (srcValue !== undefined || (key in Object(object)));
    };
  }

  /**
   * A specialized version of `_.memoize` which clears the memoized function's
   * cache when it exceeds `MAX_MEMOIZE_SIZE`.
   *
   * @private
   * @param {Function} func The function to have its output memoized.
   * @returns {Function} Returns the new memoized function.
   */
  function memoizeCapped(func) {
    var result = memoize(func, function(key) {
      if (cache.size === MAX_MEMOIZE_SIZE) {
        cache.clear();
      }
      return key;
    });

    var cache = result.cache;
    return result;
  }

  /**
   * This function is like
   * [`Object.keys`](http://ecma-international.org/ecma-262/7.0/#sec-object.keys)
   * except that it includes inherited enumerable properties.
   *
   * @private
   * @param {Object} object The object to query.
   * @returns {Array} Returns the array of property names.
   */
  function nativeKeysIn(object) {
    var result = [];
    if (object != null) {
      for (var key in Object(object)) {
        result.push(key);
      }
    }
    return result;
  }

  /**
   * Converts `value` to a string using `Object.prototype.toString`.
   *
   * @private
   * @param {*} value The value to convert.
   * @returns {string} Returns the converted string.
   */
  function objectToString(value) {
    return nativeObjectToString.call(value);
  }

  /**
   * A specialized version of `baseRest` which transforms the rest array.
   *
   * @private
   * @param {Function} func The function to apply a rest parameter to.
   * @param {number} [start=func.length-1] The start position of the rest parameter.
   * @param {Function} transform The rest array transform.
   * @returns {Function} Returns the new function.
   */
  function overRest(func, start, transform) {
    start = nativeMax(start === undefined ? (func.length - 1) : start, 0);
    return function() {
      var args = arguments,
          index = -1,
          length = nativeMax(args.length - start, 0),
          array = Array(length);

      while (++index < length) {
        array[index] = args[start + index];
      }
      index = -1;
      var otherArgs = Array(start + 1);
      while (++index < start) {
        otherArgs[index] = args[index];
      }
      otherArgs[start] = transform(array);
      return apply(func, this, otherArgs);
    };
  }

  /**
   * Gets the parent value at `path` of `object`.
   *
   * @private
   * @param {Object} object The object to query.
   * @param {Array} path The path to get the parent value of.
   * @returns {*} Returns the parent value.
   */
  function parent(object, path) {
    return path.length < 2 ? object : baseGet(object, baseSlice(path, 0, -1));
  }

  /**
   * Reorder `array` according to the specified indexes where the element at
   * the first index is assigned as the first element, the element at
   * the second index is assigned as the second element, and so on.
   *
   * @private
   * @param {Array} array The array to reorder.
   * @param {Array} indexes The arranged array indexes.
   * @returns {Array} Returns `array`.
   */
  function reorder(array, indexes) {
    var arrLength = array.length,
        length = nativeMin(indexes.length, arrLength),
        oldArray = copyArray(array);

    while (length--) {
      var index = indexes[length];
      array[length] = isIndex(index, arrLength) ? oldArray[index] : undefined;
    }
    return array;
  }

  /**
   * Gets the value at `key`, unless `key` is "__proto__" or "constructor".
   *
   * @private
   * @param {Object} object The object to query.
   * @param {string} key The key of the property to get.
   * @returns {*} Returns the property value.
   */
  function safeGet(object, key) {
    if (key === 'constructor' && typeof object[key] === 'function') {
      return;
    }

    if (key == '__proto__') {
      return;
    }

    return object[key];
  }

  /**
   * Sets metadata for `func`.
   *
   * **Note:** If this function becomes hot, i.e. is invoked a lot in a short
   * period of time, it will trip its breaker and transition to an identity
   * function to avoid garbage collection pauses in V8. See
   * [V8 issue 2070](https://bugs.chromium.org/p/v8/issues/detail?id=2070)
   * for more details.
   *
   * @private
   * @param {Function} func The function to associate metadata with.
   * @param {*} data The metadata.
   * @returns {Function} Returns `func`.
   */
  var setData = shortOut(baseSetData);

  /**
   * Sets the `toString` method of `func` to return `string`.
   *
   * @private
   * @param {Function} func The function to modify.
   * @param {Function} string The `toString` result.
   * @returns {Function} Returns `func`.
   */
  var setToString = shortOut(baseSetToString);

  /**
   * Sets the `toString` method of `wrapper` to mimic the source of `reference`
   * with wrapper details in a comment at the top of the source body.
   *
   * @private
   * @param {Function} wrapper The function to modify.
   * @param {Function} reference The reference function.
   * @param {number} bitmask The bitmask flags. See `createWrap` for more details.
   * @returns {Function} Returns `wrapper`.
   */
  function setWrapToString(wrapper, reference, bitmask) {
    var source = (reference + '');
    return setToString(wrapper, insertWrapDetails(source, updateWrapDetails(getWrapDetails(source), bitmask)));
  }

  /**
   * Creates a function that'll short out and invoke `identity` instead
   * of `func` when it's called `HOT_COUNT` or more times in `HOT_SPAN`
   * milliseconds.
   *
   * @private
   * @param {Function} func The function to restrict.
   * @returns {Function} Returns the new shortable function.
   */
  function shortOut(func) {
    var count = 0,
        lastCalled = 0;

    return function() {
      var stamp = nativeNow(),
          remaining = HOT_SPAN - (stamp - lastCalled);

      lastCalled = stamp;
      if (remaining > 0) {
        if (++count >= HOT_COUNT) {
          return arguments[0];
        }
      } else {
        count = 0;
      }
      return func.apply(undefined, arguments);
    };
  }

  /**
   * Converts `string` to a property path array.
   *
   * @private
   * @param {string} string The string to convert.
   * @returns {Array} Returns the property path array.
   */
  var stringToPath = memoizeCapped(function(string) {
    var result = [];
    if (string.charCodeAt(0) === 46 /* . */) {
      result.push('');
    }
    string.replace(rePropName, function(match, number, quote, subString) {
      result.push(quote ? subString.replace(reEscapeChar, '$1') : (number || match));
    });
    return result;
  });

  /**
   * Converts `value` to a string key if it's not a string or symbol.
   *
   * @private
   * @param {*} value The value to inspect.
   * @returns {string|symbol} Returns the key.
   */
  function toKey(value) {
    if (typeof value == 'string' || isSymbol(value)) {
      return value;
    }
    var result = (value + '');
    return (result == '0' && (1 / value) == -INFINITY) ? '-0' : result;
  }

  /**
   * Converts `func` to its source code.
   *
   * @private
   * @param {Function} func The function to convert.
   * @returns {string} Returns the source code.
   */
  function toSource(func) {
    if (func != null) {
      try {
        return funcToString.call(func);
      } catch (e) {}
      try {
        return (func + '');
      } catch (e) {}
    }
    return '';
  }

  /**
   * Updates wrapper `details` based on `bitmask` flags.
   *
   * @private
   * @returns {Array} details The details to modify.
   * @param {number} bitmask The bitmask flags. See `createWrap` for more details.
   * @returns {Array} Returns `details`.
   */
  function updateWrapDetails(details, bitmask) {
    arrayEach(wrapFlags, function(pair) {
      var value = '_.' + pair[0];
      if ((bitmask & pair[1]) && !arrayIncludes(details, value)) {
        details.push(value);
      }
    });
    return details.sort();
  }

  /**
   * Creates a clone of `wrapper`.
   *
   * @private
   * @param {Object} wrapper The wrapper to clone.
   * @returns {Object} Returns the cloned wrapper.
   */
  function wrapperClone(wrapper) {
    if (wrapper instanceof LazyWrapper) {
      return wrapper.clone();
    }
    var result = new LodashWrapper(wrapper.__wrapped__, wrapper.__chain__);
    result.__actions__ = copyArray(wrapper.__actions__);
    result.__index__  = wrapper.__index__;
    result.__values__ = wrapper.__values__;
    return result;
  }

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

  /**
   * Creates an array with all falsey values removed. The values `false`, `null`,
   * `0`, `""`, `undefined`, and `NaN` are falsey.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Array
   * @param {Array} array The array to compact.
   * @returns {Array} Returns the new array of filtered values.
   * @example
   *
   * _.compact([0, 1, false, 2, '', 3]);
   * // => [1, 2, 3]
   */
  function compact(array) {
    var index = -1,
        length = array == null ? 0 : array.length,
        resIndex = 0,
        result = [];

    while (++index < length) {
      var value = array[index];
      if (value) {
        result[resIndex++] = value;
      }
    }
    return result;
  }

  /**
   * This method is like `_.find` except that it returns the index of the first
   * element `predicate` returns truthy for instead of the element itself.
   *
   * @static
   * @memberOf _
   * @since 1.1.0
   * @category Array
   * @param {Array} array The array to inspect.
   * @param {Function} [predicate=_.identity] The function invoked per iteration.
   * @param {number} [fromIndex=0] The index to search from.
   * @returns {number} Returns the index of the found element, else `-1`.
   * @example
   *
   * var users = [
   *   { 'user': 'barney',  'active': false },
   *   { 'user': 'fred',    'active': false },
   *   { 'user': 'pebbles', 'active': true }
   * ];
   *
   * _.findIndex(users, function(o) { return o.user == 'barney'; });
   * // => 0
   *
   * // The `_.matches` iteratee shorthand.
   * _.findIndex(users, { 'user': 'fred', 'active': false });
   * // => 1
   *
   * // The `_.matchesProperty` iteratee shorthand.
   * _.findIndex(users, ['active', false]);
   * // => 0
   *
   * // The `_.property` iteratee shorthand.
   * _.findIndex(users, 'active');
   * // => 2
   */
  function findIndex(array, predicate, fromIndex) {
    var length = array == null ? 0 : array.length;
    if (!length) {
      return -1;
    }
    var index = fromIndex == null ? 0 : toInteger(fromIndex);
    if (index < 0) {
      index = nativeMax(length + index, 0);
    }
    return baseFindIndex(array, getIteratee(predicate, 3), index);
  }

  /**
   * Flattens `array` a single level deep.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Array
   * @param {Array} array The array to flatten.
   * @returns {Array} Returns the new flattened array.
   * @example
   *
   * _.flatten([1, [2, [3, [4]], 5]]);
   * // => [1, 2, [3, [4]], 5]
   */
  function flatten(array) {
    var length = array == null ? 0 : array.length;
    return length ? baseFlatten(array, 1) : [];
  }

  /**
   * Gets the first element of `array`.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @alias first
   * @category Array
   * @param {Array} array The array to query.
   * @returns {*} Returns the first element of `array`.
   * @example
   *
   * _.head([1, 2, 3]);
   * // => 1
   *
   * _.head([]);
   * // => undefined
   */
  function head(array) {
    return (array && array.length) ? array[0] : undefined;
  }

  /**
   * Creates an array of unique values that are included in all given arrays
   * using [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
   * for equality comparisons. The order and references of result values are
   * determined by the first array.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Array
   * @param {...Array} [arrays] The arrays to inspect.
   * @returns {Array} Returns the new array of intersecting values.
   * @example
   *
   * _.intersection([2, 1], [2, 3]);
   * // => [2]
   */
  var intersection = baseRest(function(arrays) {
    var mapped = arrayMap(arrays, castArrayLikeObject);
    return (mapped.length && mapped[0] === arrays[0])
      ? baseIntersection(mapped)
      : [];
  });

  /**
   * Gets the last element of `array`.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Array
   * @param {Array} array The array to query.
   * @returns {*} Returns the last element of `array`.
   * @example
   *
   * _.last([1, 2, 3]);
   * // => 3
   */
  function last(array) {
    var length = array == null ? 0 : array.length;
    return length ? array[length - 1] : undefined;
  }

  /**
   * Reverses `array` so that the first element becomes the last, the second
   * element becomes the second to last, and so on.
   *
   * **Note:** This method mutates `array` and is based on
   * [`Array#reverse`](https://mdn.io/Array/reverse).
   *
   * @static
   * @memberOf _
   * @since 4.0.0
   * @category Array
   * @param {Array} array The array to modify.
   * @returns {Array} Returns `array`.
   * @example
   *
   * var array = [1, 2, 3];
   *
   * _.reverse(array);
   * // => [3, 2, 1]
   *
   * console.log(array);
   * // => [3, 2, 1]
   */
  function reverse(array) {
    return array == null ? array : nativeReverse.call(array);
  }

  /**
   * Creates an array of unique values, in order, from all given arrays using
   * [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
   * for equality comparisons.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Array
   * @param {...Array} [arrays] The arrays to inspect.
   * @returns {Array} Returns the new array of combined values.
   * @example
   *
   * _.union([2], [1, 2]);
   * // => [2, 1]
   */
  var union = baseRest(function(arrays) {
    return baseUniq(baseFlatten(arrays, 1, isArrayLikeObject, true));
  });

  /**
   * Creates a duplicate-free version of an array, using
   * [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
   * for equality comparisons, in which only the first occurrence of each element
   * is kept. The order of result values is determined by the order they occur
   * in the array.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Array
   * @param {Array} array The array to inspect.
   * @returns {Array} Returns the new duplicate free array.
   * @example
   *
   * _.uniq([2, 1, 2]);
   * // => [2, 1]
   */
  function uniq(array) {
    return (array && array.length) ? baseUniq(array) : [];
  }

  /**
   * Creates an array excluding all given values using
   * [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
   * for equality comparisons.
   *
   * **Note:** Unlike `_.pull`, this method returns a new array.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Array
   * @param {Array} array The array to inspect.
   * @param {...*} [values] The values to exclude.
   * @returns {Array} Returns the new array of filtered values.
   * @see _.difference, _.xor
   * @example
   *
   * _.without([2, 1, 2, 3], 1, 2);
   * // => [3]
   */
  var without = baseRest(function(array, values) {
    return isArrayLikeObject(array)
      ? baseDifference(array, values)
      : [];
  });

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

  /**
   * Creates a `lodash` wrapper instance that wraps `value` with explicit method
   * chain sequences enabled. The result of such sequences must be unwrapped
   * with `_#value`.
   *
   * @static
   * @memberOf _
   * @since 1.3.0
   * @category Seq
   * @param {*} value The value to wrap.
   * @returns {Object} Returns the new `lodash` wrapper instance.
   * @example
   *
   * var users = [
   *   { 'user': 'barney',  'age': 36 },
   *   { 'user': 'fred',    'age': 40 },
   *   { 'user': 'pebbles', 'age': 1 }
   * ];
   *
   * var youngest = _
   *   .chain(users)
   *   .sortBy('age')
   *   .map(function(o) {
   *     return o.user + ' is ' + o.age;
   *   })
   *   .head()
   *   .value();
   * // => 'pebbles is 1'
   */
  function chain(value) {
    var result = lodash(value);
    result.__chain__ = true;
    return result;
  }

  /**
   * This method invokes `interceptor` and returns `value`. The interceptor
   * is invoked with one argument; (value). The purpose of this method is to
   * "tap into" a method chain sequence in order to modify intermediate results.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Seq
   * @param {*} value The value to provide to `interceptor`.
   * @param {Function} interceptor The function to invoke.
   * @returns {*} Returns `value`.
   * @example
   *
   * _([1, 2, 3])
   *  .tap(function(array) {
   *    // Mutate input array.
   *    array.pop();
   *  })
   *  .reverse()
   *  .value();
   * // => [2, 1]
   */
  function tap(value, interceptor) {
    interceptor(value);
    return value;
  }

  /**
   * This method is like `_.tap` except that it returns the result of `interceptor`.
   * The purpose of this method is to "pass thru" values replacing intermediate
   * results in a method chain sequence.
   *
   * @static
   * @memberOf _
   * @since 3.0.0
   * @category Seq
   * @param {*} value The value to provide to `interceptor`.
   * @param {Function} interceptor The function to invoke.
   * @returns {*} Returns the result of `interceptor`.
   * @example
   *
   * _('  abc  ')
   *  .chain()
   *  .trim()
   *  .thru(function(value) {
   *    return [value];
   *  })
   *  .value();
   * // => ['abc']
   */
  function thru(value, interceptor) {
    return interceptor(value);
  }

  /**
   * This method is the wrapper version of `_.at`.
   *
   * @name at
   * @memberOf _
   * @since 1.0.0
   * @category Seq
   * @param {...(string|string[])} [paths] The property paths to pick.
   * @returns {Object} Returns the new `lodash` wrapper instance.
   * @example
   *
   * var object = { 'a': [{ 'b': { 'c': 3 } }, 4] };
   *
   * _(object).at(['a[0].b.c', 'a[1]']).value();
   * // => [3, 4]
   */
  var wrapperAt = flatRest(function(paths) {
    var length = paths.length,
        start = length ? paths[0] : 0,
        value = this.__wrapped__,
        interceptor = function(object) { return baseAt(object, paths); };

    if (length > 1 || this.__actions__.length ||
        !(value instanceof LazyWrapper) || !isIndex(start)) {
      return this.thru(interceptor);
    }
    value = value.slice(start, +start + (length ? 1 : 0));
    value.__actions__.push({
      'func': thru,
      'args': [interceptor],
      'thisArg': undefined
    });
    return new LodashWrapper(value, this.__chain__).thru(function(array) {
      if (length && !array.length) {
        array.push(undefined);
      }
      return array;
    });
  });

  /**
   * Creates a `lodash` wrapper instance with explicit method chain sequences enabled.
   *
   * @name chain
   * @memberOf _
   * @since 0.1.0
   * @category Seq
   * @returns {Object} Returns the new `lodash` wrapper instance.
   * @example
   *
   * var users = [
   *   { 'user': 'barney', 'age': 36 },
   *   { 'user': 'fred',   'age': 40 }
   * ];
   *
   * // A sequence without explicit chaining.
   * _(users).head();
   * // => { 'user': 'barney', 'age': 36 }
   *
   * // A sequence with explicit chaining.
   * _(users)
   *   .chain()
   *   .head()
   *   .pick('user')
   *   .value();
   * // => { 'user': 'barney' }
   */
  function wrapperChain() {
    return chain(this);
  }

  /**
   * Executes the chain sequence and returns the wrapped result.
   *
   * @name commit
   * @memberOf _
   * @since 3.2.0
   * @category Seq
   * @returns {Object} Returns the new `lodash` wrapper instance.
   * @example
   *
   * var array = [1, 2];
   * var wrapped = _(array).push(3);
   *
   * console.log(array);
   * // => [1, 2]
   *
   * wrapped = wrapped.commit();
   * console.log(array);
   * // => [1, 2, 3]
   *
   * wrapped.last();
   * // => 3
   *
   * console.log(array);
   * // => [1, 2, 3]
   */
  function wrapperCommit() {
    return new LodashWrapper(this.value(), this.__chain__);
  }

  /**
   * Gets the next value on a wrapped object following the
   * [iterator protocol](https://mdn.io/iteration_protocols#iterator).
   *
   * @name next
   * @memberOf _
   * @since 4.0.0
   * @category Seq
   * @returns {Object} Returns the next iterator value.
   * @example
   *
   * var wrapped = _([1, 2]);
   *
   * wrapped.next();
   * // => { 'done': false, 'value': 1 }
   *
   * wrapped.next();
   * // => { 'done': false, 'value': 2 }
   *
   * wrapped.next();
   * // => { 'done': true, 'value': undefined }
   */
  function wrapperNext() {
    if (this.__values__ === undefined) {
      this.__values__ = toArray(this.value());
    }
    var done = this.__index__ >= this.__values__.length,
        value = done ? undefined : this.__values__[this.__index__++];

    return { 'done': done, 'value': value };
  }

  /**
   * Enables the wrapper to be iterable.
   *
   * @name Symbol.iterator
   * @memberOf _
   * @since 4.0.0
   * @category Seq
   * @returns {Object} Returns the wrapper object.
   * @example
   *
   * var wrapped = _([1, 2]);
   *
   * wrapped[Symbol.iterator]() === wrapped;
   * // => true
   *
   * Array.from(wrapped);
   * // => [1, 2]
   */
  function wrapperToIterator() {
    return this;
  }

  /**
   * Creates a clone of the chain sequence planting `value` as the wrapped value.
   *
   * @name plant
   * @memberOf _
   * @since 3.2.0
   * @category Seq
   * @param {*} value The value to plant.
   * @returns {Object} Returns the new `lodash` wrapper instance.
   * @example
   *
   * function square(n) {
   *   return n * n;
   * }
   *
   * var wrapped = _([1, 2]).map(square);
   * var other = wrapped.plant([3, 4]);
   *
   * other.value();
   * // => [9, 16]
   *
   * wrapped.value();
   * // => [1, 4]
   */
  function wrapperPlant(value) {
    var result,
        parent = this;

    while (parent instanceof baseLodash) {
      var clone = wrapperClone(parent);
      clone.__index__ = 0;
      clone.__values__ = undefined;
      if (result) {
        previous.__wrapped__ = clone;
      } else {
        result = clone;
      }
      var previous = clone;
      parent = parent.__wrapped__;
    }
    previous.__wrapped__ = value;
    return result;
  }

  /**
   * This method is the wrapper version of `_.reverse`.
   *
   * **Note:** This method mutates the wrapped array.
   *
   * @name reverse
   * @memberOf _
   * @since 0.1.0
   * @category Seq
   * @returns {Object} Returns the new `lodash` wrapper instance.
   * @example
   *
   * var array = [1, 2, 3];
   *
   * _(array).reverse().value()
   * // => [3, 2, 1]
   *
   * console.log(array);
   * // => [3, 2, 1]
   */
  function wrapperReverse() {
    var value = this.__wrapped__;
    if (value instanceof LazyWrapper) {
      var wrapped = value;
      if (this.__actions__.length) {
        wrapped = new LazyWrapper(this);
      }
      wrapped = wrapped.reverse();
      wrapped.__actions__.push({
        'func': thru,
        'args': [reverse],
        'thisArg': undefined
      });
      return new LodashWrapper(wrapped, this.__chain__);
    }
    return this.thru(reverse);
  }

  /**
   * Executes the chain sequence to resolve the unwrapped value.
   *
   * @name value
   * @memberOf _
   * @since 0.1.0
   * @alias toJSON, valueOf
   * @category Seq
   * @returns {*} Returns the resolved unwrapped value.
   * @example
   *
   * _([1, 2, 3]).value();
   * // => [1, 2, 3]
   */
  function wrapperValue() {
    return baseWrapperValue(this.__wrapped__, this.__actions__);
  }

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

  /**
   * Checks if `predicate` returns truthy for **all** elements of `collection`.
   * Iteration is stopped once `predicate` returns falsey. The predicate is
   * invoked with three arguments: (value, index|key, collection).
   *
   * **Note:** This method returns `true` for
   * [empty collections](https://en.wikipedia.org/wiki/Empty_set) because
   * [everything is true](https://en.wikipedia.org/wiki/Vacuous_truth) of
   * elements of empty collections.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Collection
   * @param {Array|Object} collection The collection to iterate over.
   * @param {Function} [predicate=_.identity] The function invoked per iteration.
   * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
   * @returns {boolean} Returns `true` if all elements pass the predicate check,
   *  else `false`.
   * @example
   *
   * _.every([true, 1, null, 'yes'], Boolean);
   * // => false
   *
   * var users = [
   *   { 'user': 'barney', 'age': 36, 'active': false },
   *   { 'user': 'fred',   'age': 40, 'active': false }
   * ];
   *
   * // The `_.matches` iteratee shorthand.
   * _.every(users, { 'user': 'barney', 'active': false });
   * // => false
   *
   * // The `_.matchesProperty` iteratee shorthand.
   * _.every(users, ['active', false]);
   * // => true
   *
   * // The `_.property` iteratee shorthand.
   * _.every(users, 'active');
   * // => false
   */
  function every(collection, predicate, guard) {
    var func = isArray(collection) ? arrayEvery : baseEvery;
    if (guard && isIterateeCall(collection, predicate, guard)) {
      predicate = undefined;
    }
    return func(collection, getIteratee(predicate, 3));
  }

  /**
   * Iterates over elements of `collection`, returning an array of all elements
   * `predicate` returns truthy for. The predicate is invoked with three
   * arguments: (value, index|key, collection).
   *
   * **Note:** Unlike `_.remove`, this method returns a new array.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Collection
   * @param {Array|Object} collection The collection to iterate over.
   * @param {Function} [predicate=_.identity] The function invoked per iteration.
   * @returns {Array} Returns the new filtered array.
   * @see _.reject
   * @example
   *
   * var users = [
   *   { 'user': 'barney', 'age': 36, 'active': true },
   *   { 'user': 'fred',   'age': 40, 'active': false }
   * ];
   *
   * _.filter(users, function(o) { return !o.active; });
   * // => objects for ['fred']
   *
   * // The `_.matches` iteratee shorthand.
   * _.filter(users, { 'age': 36, 'active': true });
   * // => objects for ['barney']
   *
   * // The `_.matchesProperty` iteratee shorthand.
   * _.filter(users, ['active', false]);
   * // => objects for ['fred']
   *
   * // The `_.property` iteratee shorthand.
   * _.filter(users, 'active');
   * // => objects for ['barney']
   */
  function filter(collection, predicate) {
    var func = isArray(collection) ? arrayFilter : baseFilter;
    return func(collection, getIteratee(predicate, 3));
  }

  /**
   * Iterates over elements of `collection`, returning the first element
   * `predicate` returns truthy for. The predicate is invoked with three
   * arguments: (value, index|key, collection).
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Collection
   * @param {Array|Object} collection The collection to inspect.
   * @param {Function} [predicate=_.identity] The function invoked per iteration.
   * @param {number} [fromIndex=0] The index to search from.
   * @returns {*} Returns the matched element, else `undefined`.
   * @example
   *
   * var users = [
   *   { 'user': 'barney',  'age': 36, 'active': true },
   *   { 'user': 'fred',    'age': 40, 'active': false },
   *   { 'user': 'pebbles', 'age': 1,  'active': true }
   * ];
   *
   * _.find(users, function(o) { return o.age < 40; });
   * // => object for 'barney'
   *
   * // The `_.matches` iteratee shorthand.
   * _.find(users, { 'age': 1, 'active': true });
   * // => object for 'pebbles'
   *
   * // The `_.matchesProperty` iteratee shorthand.
   * _.find(users, ['active', false]);
   * // => object for 'fred'
   *
   * // The `_.property` iteratee shorthand.
   * _.find(users, 'active');
   * // => object for 'barney'
   */
  var find = createFind(findIndex);

  /**
   * Iterates over elements of `collection` and invokes `iteratee` for each element.
   * The iteratee is invoked with three arguments: (value, index|key, collection).
   * Iteratee functions may exit iteration early by explicitly returning `false`.
   *
   * **Note:** As with other "Collections" methods, objects with a "length"
   * property are iterated like arrays. To avoid this behavior use `_.forIn`
   * or `_.forOwn` for object iteration.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @alias each
   * @category Collection
   * @param {Array|Object} collection The collection to iterate over.
   * @param {Function} [iteratee=_.identity] The function invoked per iteration.
   * @returns {Array|Object} Returns `collection`.
   * @see _.forEachRight
   * @example
   *
   * _.forEach([1, 2], function(value) {
   *   console.log(value);
   * });
   * // => Logs `1` then `2`.
   *
   * _.forEach({ 'a': 1, 'b': 2 }, function(value, key) {
   *   console.log(key);
   * });
   * // => Logs 'a' then 'b' (iteration order is not guaranteed).
   */
  function forEach(collection, iteratee) {
    var func = isArray(collection) ? arrayEach : baseEach;
    return func(collection, getIteratee(iteratee, 3));
  }

  /**
   * Creates an object composed of keys generated from the results of running
   * each element of `collection` thru `iteratee`. The order of grouped values
   * is determined by the order they occur in `collection`. The corresponding
   * value of each key is an array of elements responsible for generating the
   * key. The iteratee is invoked with one argument: (value).
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Collection
   * @param {Array|Object} collection The collection to iterate over.
   * @param {Function} [iteratee=_.identity] The iteratee to transform keys.
   * @returns {Object} Returns the composed aggregate object.
   * @example
   *
   * _.groupBy([6.1, 4.2, 6.3], Math.floor);
   * // => { '4': [4.2], '6': [6.1, 6.3] }
   *
   * // The `_.property` iteratee shorthand.
   * _.groupBy(['one', 'two', 'three'], 'length');
   * // => { '3': ['one', 'two'], '5': ['three'] }
   */
  var groupBy = createAggregator(function(result, value, key) {
    if (hasOwnProperty.call(result, key)) {
      result[key].push(value);
    } else {
      baseAssignValue(result, key, [value]);
    }
  });

  /**
   * Creates an array of values by running each element in `collection` thru
   * `iteratee`. The iteratee is invoked with three arguments:
   * (value, index|key, collection).
   *
   * Many lodash methods are guarded to work as iteratees for methods like
   * `_.every`, `_.filter`, `_.map`, `_.mapValues`, `_.reject`, and `_.some`.
   *
   * The guarded methods are:
   * `ary`, `chunk`, `curry`, `curryRight`, `drop`, `dropRight`, `every`,
   * `fill`, `invert`, `parseInt`, `random`, `range`, `rangeRight`, `repeat`,
   * `sampleSize`, `slice`, `some`, `sortBy`, `split`, `take`, `takeRight`,
   * `template`, `trim`, `trimEnd`, `trimStart`, and `words`
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Collection
   * @param {Array|Object} collection The collection to iterate over.
   * @param {Function} [iteratee=_.identity] The function invoked per iteration.
   * @returns {Array} Returns the new mapped array.
   * @example
   *
   * function square(n) {
   *   return n * n;
   * }
   *
   * _.map([4, 8], square);
   * // => [16, 64]
   *
   * _.map({ 'a': 4, 'b': 8 }, square);
   * // => [16, 64] (iteration order is not guaranteed)
   *
   * var users = [
   *   { 'user': 'barney' },
   *   { 'user': 'fred' }
   * ];
   *
   * // The `_.property` iteratee shorthand.
   * _.map(users, 'user');
   * // => ['barney', 'fred']
   */
  function map(collection, iteratee) {
    var func = isArray(collection) ? arrayMap : baseMap;
    return func(collection, getIteratee(iteratee, 3));
  }

  /**
   * Reduces `collection` to a value which is the accumulated result of running
   * each element in `collection` thru `iteratee`, where each successive
   * invocation is supplied the return value of the previous. If `accumulator`
   * is not given, the first element of `collection` is used as the initial
   * value. The iteratee is invoked with four arguments:
   * (accumulator, value, index|key, collection).
   *
   * Many lodash methods are guarded to work as iteratees for methods like
   * `_.reduce`, `_.reduceRight`, and `_.transform`.
   *
   * The guarded methods are:
   * `assign`, `defaults`, `defaultsDeep`, `includes`, `merge`, `orderBy`,
   * and `sortBy`
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Collection
   * @param {Array|Object} collection The collection to iterate over.
   * @param {Function} [iteratee=_.identity] The function invoked per iteration.
   * @param {*} [accumulator] The initial value.
   * @returns {*} Returns the accumulated value.
   * @see _.reduceRight
   * @example
   *
   * _.reduce([1, 2], function(sum, n) {
   *   return sum + n;
   * }, 0);
   * // => 3
   *
   * _.reduce({ 'a': 1, 'b': 2, 'c': 1 }, function(result, value, key) {
   *   (result[value] || (result[value] = [])).push(key);
   *   return result;
   * }, {});
   * // => { '1': ['a', 'c'], '2': ['b'] } (iteration order is not guaranteed)
   */
  function reduce(collection, iteratee, accumulator) {
    var func = isArray(collection) ? arrayReduce : baseReduce,
        initAccum = arguments.length < 3;

    return func(collection, getIteratee(iteratee, 4), accumulator, initAccum, baseEach);
  }

  /**
   * The opposite of `_.filter`; this method returns the elements of `collection`
   * that `predicate` does **not** return truthy for.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Collection
   * @param {Array|Object} collection The collection to iterate over.
   * @param {Function} [predicate=_.identity] The function invoked per iteration.
   * @returns {Array} Returns the new filtered array.
   * @see _.filter
   * @example
   *
   * var users = [
   *   { 'user': 'barney', 'age': 36, 'active': false },
   *   { 'user': 'fred',   'age': 40, 'active': true }
   * ];
   *
   * _.reject(users, function(o) { return !o.active; });
   * // => objects for ['fred']
   *
   * // The `_.matches` iteratee shorthand.
   * _.reject(users, { 'age': 40, 'active': true });
   * // => objects for ['barney']
   *
   * // The `_.matchesProperty` iteratee shorthand.
   * _.reject(users, ['active', false]);
   * // => objects for ['fred']
   *
   * // The `_.property` iteratee shorthand.
   * _.reject(users, 'active');
   * // => objects for ['barney']
   */
  function reject(collection, predicate) {
    var func = isArray(collection) ? arrayFilter : baseFilter;
    return func(collection, negate(getIteratee(predicate, 3)));
  }

  /**
   * Creates an array of elements, sorted in ascending order by the results of
   * running each element in a collection thru each iteratee. This method
   * performs a stable sort, that is, it preserves the original sort order of
   * equal elements. The iteratees are invoked with one argument: (value).
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Collection
   * @param {Array|Object} collection The collection to iterate over.
   * @param {...(Function|Function[])} [iteratees=[_.identity]]
   *  The iteratees to sort by.
   * @returns {Array} Returns the new sorted array.
   * @example
   *
   * var users = [
   *   { 'user': 'fred',   'age': 48 },
   *   { 'user': 'barney', 'age': 36 },
   *   { 'user': 'fred',   'age': 40 },
   *   { 'user': 'barney', 'age': 34 }
   * ];
   *
   * _.sortBy(users, [function(o) { return o.user; }]);
   * // => objects for [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 40]]
   *
   * _.sortBy(users, ['user', 'age']);
   * // => objects for [['barney', 34], ['barney', 36], ['fred', 40], ['fred', 48]]
   */
  var sortBy = baseRest(function(collection, iteratees) {
    if (collection == null) {
      return [];
    }
    var length = iteratees.length;
    if (length > 1 && isIterateeCall(collection, iteratees[0], iteratees[1])) {
      iteratees = [];
    } else if (length > 2 && isIterateeCall(iteratees[0], iteratees[1], iteratees[2])) {
      iteratees = [iteratees[0]];
    }
    return baseOrderBy(collection, baseFlatten(iteratees, 1), []);
  });

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

  /**
   * Gets the timestamp of the number of milliseconds that have elapsed since
   * the Unix epoch (1 January 1970 00:00:00 UTC).
   *
   * @static
   * @memberOf _
   * @since 2.4.0
   * @category Date
   * @returns {number} Returns the timestamp.
   * @example
   *
   * _.defer(function(stamp) {
   *   console.log(_.now() - stamp);
   * }, _.now());
   * // => Logs the number of milliseconds it took for the deferred invocation.
   */
  var now = function() {
    return root.Date.now();
  };

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

  /**
   * Creates a debounced function that delays invoking `func` until after `wait`
   * milliseconds have elapsed since the last time the debounced function was
   * invoked. The debounced function comes with a `cancel` method to cancel
   * delayed `func` invocations and a `flush` method to immediately invoke them.
   * Provide `options` to indicate whether `func` should be invoked on the
   * leading and/or trailing edge of the `wait` timeout. The `func` is invoked
   * with the last arguments provided to the debounced function. Subsequent
   * calls to the debounced function return the result of the last `func`
   * invocation.
   *
   * **Note:** If `leading` and `trailing` options are `true`, `func` is
   * invoked on the trailing edge of the timeout only if the debounced function
   * is invoked more than once during the `wait` timeout.
   *
   * If `wait` is `0` and `leading` is `false`, `func` invocation is deferred
   * until to the next tick, similar to `setTimeout` with a timeout of `0`.
   *
   * See [David Corbacho's article](https://css-tricks.com/debouncing-throttling-explained-examples/)
   * for details over the differences between `_.debounce` and `_.throttle`.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Function
   * @param {Function} func The function to debounce.
   * @param {number} [wait=0] The number of milliseconds to delay.
   * @param {Object} [options={}] The options object.
   * @param {boolean} [options.leading=false]
   *  Specify invoking on the leading edge of the timeout.
   * @param {number} [options.maxWait]
   *  The maximum time `func` is allowed to be delayed before it's invoked.
   * @param {boolean} [options.trailing=true]
   *  Specify invoking on the trailing edge of the timeout.
   * @returns {Function} Returns the new debounced function.
   * @example
   *
   * // Avoid costly calculations while the window size is in flux.
   * jQuery(window).on('resize', _.debounce(calculateLayout, 150));
   *
   * // Invoke `sendMail` when clicked, debouncing subsequent calls.
   * jQuery(element).on('click', _.debounce(sendMail, 300, {
   *   'leading': true,
   *   'trailing': false
   * }));
   *
   * // Ensure `batchLog` is invoked once after 1 second of debounced calls.
   * var debounced = _.debounce(batchLog, 250, { 'maxWait': 1000 });
   * var source = new EventSource('/stream');
   * jQuery(source).on('message', debounced);
   *
   * // Cancel the trailing debounced invocation.
   * jQuery(window).on('popstate', debounced.cancel);
   */
  function debounce(func, wait, options) {
    var lastArgs,
        lastThis,
        maxWait,
        result,
        timerId,
        lastCallTime,
        lastInvokeTime = 0,
        leading = false,
        maxing = false,
        trailing = true;

    if (typeof func != 'function') {
      throw new TypeError(FUNC_ERROR_TEXT);
    }
    wait = toNumber(wait) || 0;
    if (isObject(options)) {
      leading = !!options.leading;
      maxing = 'maxWait' in options;
      maxWait = maxing ? nativeMax(toNumber(options.maxWait) || 0, wait) : maxWait;
      trailing = 'trailing' in options ? !!options.trailing : trailing;
    }

    function invokeFunc(time) {
      var args = lastArgs,
          thisArg = lastThis;

      lastArgs = lastThis = undefined;
      lastInvokeTime = time;
      result = func.apply(thisArg, args);
      return result;
    }

    function leadingEdge(time) {
      // Reset any `maxWait` timer.
      lastInvokeTime = time;
      // Start the timer for the trailing edge.
      timerId = setTimeout(timerExpired, wait);
      // Invoke the leading edge.
      return leading ? invokeFunc(time) : result;
    }

    function remainingWait(time) {
      var timeSinceLastCall = time - lastCallTime,
          timeSinceLastInvoke = time - lastInvokeTime,
          timeWaiting = wait - timeSinceLastCall;

      return maxing
        ? nativeMin(timeWaiting, maxWait - timeSinceLastInvoke)
        : timeWaiting;
    }

    function shouldInvoke(time) {
      var timeSinceLastCall = time - lastCallTime,
          timeSinceLastInvoke = time - lastInvokeTime;

      // Either this is the first call, activity has stopped and we're at the
      // trailing edge, the system time has gone backwards and we're treating
      // it as the trailing edge, or we've hit the `maxWait` limit.
      return (lastCallTime === undefined || (timeSinceLastCall >= wait) ||
        (timeSinceLastCall < 0) || (maxing && timeSinceLastInvoke >= maxWait));
    }

    function timerExpired() {
      var time = now();
      if (shouldInvoke(time)) {
        return trailingEdge(time);
      }
      // Restart the timer.
      timerId = setTimeout(timerExpired, remainingWait(time));
    }

    function trailingEdge(time) {
      timerId = undefined;

      // Only invoke if we have `lastArgs` which means `func` has been
      // debounced at least once.
      if (trailing && lastArgs) {
        return invokeFunc(time);
      }
      lastArgs = lastThis = undefined;
      return result;
    }

    function cancel() {
      if (timerId !== undefined) {
        clearTimeout(timerId);
      }
      lastInvokeTime = 0;
      lastArgs = lastCallTime = lastThis = timerId = undefined;
    }

    function flush() {
      return timerId === undefined ? result : trailingEdge(now());
    }

    function debounced() {
      var time = now(),
          isInvoking = shouldInvoke(time);

      lastArgs = arguments;
      lastThis = this;
      lastCallTime = time;

      if (isInvoking) {
        if (timerId === undefined) {
          return leadingEdge(lastCallTime);
        }
        if (maxing) {
          // Handle invocations in a tight loop.
          clearTimeout(timerId);
          timerId = setTimeout(timerExpired, wait);
          return invokeFunc(lastCallTime);
        }
      }
      if (timerId === undefined) {
        timerId = setTimeout(timerExpired, wait);
      }
      return result;
    }
    debounced.cancel = cancel;
    debounced.flush = flush;
    return debounced;
  }

  /**
   * Invokes `func` after `wait` milliseconds. Any additional arguments are
   * provided to `func` when it's invoked.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Function
   * @param {Function} func The function to delay.
   * @param {number} wait The number of milliseconds to delay invocation.
   * @param {...*} [args] The arguments to invoke `func` with.
   * @returns {number} Returns the timer id.
   * @example
   *
   * _.delay(function(text) {
   *   console.log(text);
   * }, 1000, 'later');
   * // => Logs 'later' after one second.
   */
  var delay = baseRest(function(func, wait, args) {
    return baseDelay(func, toNumber(wait) || 0, args);
  });

  /**
   * Creates a function that memoizes the result of `func`. If `resolver` is
   * provided, it determines the cache key for storing the result based on the
   * arguments provided to the memoized function. By default, the first argument
   * provided to the memoized function is used as the map cache key. The `func`
   * is invoked with the `this` binding of the memoized function.
   *
   * **Note:** The cache is exposed as the `cache` property on the memoized
   * function. Its creation may be customized by replacing the `_.memoize.Cache`
   * constructor with one whose instances implement the
   * [`Map`](http://ecma-international.org/ecma-262/7.0/#sec-properties-of-the-map-prototype-object)
   * method interface of `clear`, `delete`, `get`, `has`, and `set`.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Function
   * @param {Function} func The function to have its output memoized.
   * @param {Function} [resolver] The function to resolve the cache key.
   * @returns {Function} Returns the new memoized function.
   * @example
   *
   * var object = { 'a': 1, 'b': 2 };
   * var other = { 'c': 3, 'd': 4 };
   *
   * var values = _.memoize(_.values);
   * values(object);
   * // => [1, 2]
   *
   * values(other);
   * // => [3, 4]
   *
   * object.a = 2;
   * values(object);
   * // => [1, 2]
   *
   * // Modify the result cache.
   * values.cache.set(object, ['a', 'b']);
   * values(object);
   * // => ['a', 'b']
   *
   * // Replace `_.memoize.Cache`.
   * _.memoize.Cache = WeakMap;
   */
  function memoize(func, resolver) {
    if (typeof func != 'function' || (resolver != null && typeof resolver != 'function')) {
      throw new TypeError(FUNC_ERROR_TEXT);
    }
    var memoized = function() {
      var args = arguments,
          key = resolver ? resolver.apply(this, args) : args[0],
          cache = memoized.cache;

      if (cache.has(key)) {
        return cache.get(key);
      }
      var result = func.apply(this, args);
      memoized.cache = cache.set(key, result) || cache;
      return result;
    };
    memoized.cache = new (memoize.Cache || MapCache);
    return memoized;
  }

  // Expose `MapCache`.
  memoize.Cache = MapCache;

  /**
   * Creates a function that negates the result of the predicate `func`. The
   * `func` predicate is invoked with the `this` binding and arguments of the
   * created function.
   *
   * @static
   * @memberOf _
   * @since 3.0.0
   * @category Function
   * @param {Function} predicate The predicate to negate.
   * @returns {Function} Returns the new negated function.
   * @example
   *
   * function isEven(n) {
   *   return n % 2 == 0;
   * }
   *
   * _.filter([1, 2, 3, 4, 5, 6], _.negate(isEven));
   * // => [1, 3, 5]
   */
  function negate(predicate) {
    if (typeof predicate != 'function') {
      throw new TypeError(FUNC_ERROR_TEXT);
    }
    return function() {
      var args = arguments;
      switch (args.length) {
        case 0: return !predicate.call(this);
        case 1: return !predicate.call(this, args[0]);
        case 2: return !predicate.call(this, args[0], args[1]);
        case 3: return !predicate.call(this, args[0], args[1], args[2]);
      }
      return !predicate.apply(this, args);
    };
  }

  /**
   * Creates a throttled function that only invokes `func` at most once per
   * every `wait` milliseconds. The throttled function comes with a `cancel`
   * method to cancel delayed `func` invocations and a `flush` method to
   * immediately invoke them. Provide `options` to indicate whether `func`
   * should be invoked on the leading and/or trailing edge of the `wait`
   * timeout. The `func` is invoked with the last arguments provided to the
   * throttled function. Subsequent calls to the throttled function return the
   * result of the last `func` invocation.
   *
   * **Note:** If `leading` and `trailing` options are `true`, `func` is
   * invoked on the trailing edge of the timeout only if the throttled function
   * is invoked more than once during the `wait` timeout.
   *
   * If `wait` is `0` and `leading` is `false`, `func` invocation is deferred
   * until to the next tick, similar to `setTimeout` with a timeout of `0`.
   *
   * See [David Corbacho's article](https://css-tricks.com/debouncing-throttling-explained-examples/)
   * for details over the differences between `_.throttle` and `_.debounce`.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Function
   * @param {Function} func The function to throttle.
   * @param {number} [wait=0] The number of milliseconds to throttle invocations to.
   * @param {Object} [options={}] The options object.
   * @param {boolean} [options.leading=true]
   *  Specify invoking on the leading edge of the timeout.
   * @param {boolean} [options.trailing=true]
   *  Specify invoking on the trailing edge of the timeout.
   * @returns {Function} Returns the new throttled function.
   * @example
   *
   * // Avoid excessively updating the position while scrolling.
   * jQuery(window).on('scroll', _.throttle(updatePosition, 100));
   *
   * // Invoke `renewToken` when the click event is fired, but not more than once every 5 minutes.
   * var throttled = _.throttle(renewToken, 300000, { 'trailing': false });
   * jQuery(element).on('click', throttled);
   *
   * // Cancel the trailing throttled invocation.
   * jQuery(window).on('popstate', throttled.cancel);
   */
  function throttle(func, wait, options) {
    var leading = true,
        trailing = true;

    if (typeof func != 'function') {
      throw new TypeError(FUNC_ERROR_TEXT);
    }
    if (isObject(options)) {
      leading = 'leading' in options ? !!options.leading : leading;
      trailing = 'trailing' in options ? !!options.trailing : trailing;
    }
    return debounce(func, wait, {
      'leading': leading,
      'maxWait': wait,
      'trailing': trailing
    });
  }

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

  /**
   * Creates a shallow clone of `value`.
   *
   * **Note:** This method is loosely based on the
   * [structured clone algorithm](https://mdn.io/Structured_clone_algorithm)
   * and supports cloning arrays, array buffers, booleans, date objects, maps,
   * numbers, `Object` objects, regexes, sets, strings, symbols, and typed
   * arrays. The own enumerable properties of `arguments` objects are cloned
   * as plain objects. An empty object is returned for uncloneable values such
   * as error objects, functions, DOM nodes, and WeakMaps.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Lang
   * @param {*} value The value to clone.
   * @returns {*} Returns the cloned value.
   * @see _.cloneDeep
   * @example
   *
   * var objects = [{ 'a': 1 }, { 'b': 2 }];
   *
   * var shallow = _.clone(objects);
   * console.log(shallow[0] === objects[0]);
   * // => true
   */
  function clone(value) {
    return baseClone(value, CLONE_SYMBOLS_FLAG);
  }

  /**
   * Performs a
   * [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
   * comparison between two values to determine if they are equivalent.
   *
   * @static
   * @memberOf _
   * @since 4.0.0
   * @category Lang
   * @param {*} value The value to compare.
   * @param {*} other The other value to compare.
   * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
   * @example
   *
   * var object = { 'a': 1 };
   * var other = { 'a': 1 };
   *
   * _.eq(object, object);
   * // => true
   *
   * _.eq(object, other);
   * // => false
   *
   * _.eq('a', 'a');
   * // => true
   *
   * _.eq('a', Object('a'));
   * // => false
   *
   * _.eq(NaN, NaN);
   * // => true
   */
  function eq(value, other) {
    return value === other || (value !== value && other !== other);
  }

  /**
   * Checks if `value` is likely an `arguments` object.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Lang
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is an `arguments` object,
   *  else `false`.
   * @example
   *
   * _.isArguments(function() { return arguments; }());
   * // => true
   *
   * _.isArguments([1, 2, 3]);
   * // => false
   */
  var isArguments = baseIsArguments(function() { return arguments; }()) ? baseIsArguments : function(value) {
    return isObjectLike(value) && hasOwnProperty.call(value, 'callee') &&
      !propertyIsEnumerable.call(value, 'callee');
  };

  /**
   * Checks if `value` is classified as an `Array` object.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Lang
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is an array, else `false`.
   * @example
   *
   * _.isArray([1, 2, 3]);
   * // => true
   *
   * _.isArray(document.body.children);
   * // => false
   *
   * _.isArray('abc');
   * // => false
   *
   * _.isArray(_.noop);
   * // => false
   */
  var isArray = Array.isArray;

  /**
   * Checks if `value` is array-like. A value is considered array-like if it's
   * not a function and has a `value.length` that's an integer greater than or
   * equal to `0` and less than or equal to `Number.MAX_SAFE_INTEGER`.
   *
   * @static
   * @memberOf _
   * @since 4.0.0
   * @category Lang
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is array-like, else `false`.
   * @example
   *
   * _.isArrayLike([1, 2, 3]);
   * // => true
   *
   * _.isArrayLike(document.body.children);
   * // => true
   *
   * _.isArrayLike('abc');
   * // => true
   *
   * _.isArrayLike(_.noop);
   * // => false
   */
  function isArrayLike(value) {
    return value != null && isLength(value.length) && !isFunction(value);
  }

  /**
   * This method is like `_.isArrayLike` except that it also checks if `value`
   * is an object.
   *
   * @static
   * @memberOf _
   * @since 4.0.0
   * @category Lang
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is an array-like object,
   *  else `false`.
   * @example
   *
   * _.isArrayLikeObject([1, 2, 3]);
   * // => true
   *
   * _.isArrayLikeObject(document.body.children);
   * // => true
   *
   * _.isArrayLikeObject('abc');
   * // => false
   *
   * _.isArrayLikeObject(_.noop);
   * // => false
   */
  function isArrayLikeObject(value) {
    return isObjectLike(value) && isArrayLike(value);
  }

  /**
   * Checks if `value` is a buffer.
   *
   * @static
   * @memberOf _
   * @since 4.3.0
   * @category Lang
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is a buffer, else `false`.
   * @example
   *
   * _.isBuffer(new Buffer(2));
   * // => true
   *
   * _.isBuffer(new Uint8Array(2));
   * // => false
   */
  var isBuffer = nativeIsBuffer || stubFalse;

  /**
   * Checks if `value` is an empty object, collection, map, or set.
   *
   * Objects are considered empty if they have no own enumerable string keyed
   * properties.
   *
   * Array-like values such as `arguments` objects, arrays, buffers, strings, or
   * jQuery-like collections are considered empty if they have a `length` of `0`.
   * Similarly, maps and sets are considered empty if they have a `size` of `0`.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Lang
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is empty, else `false`.
   * @example
   *
   * _.isEmpty(null);
   * // => true
   *
   * _.isEmpty(true);
   * // => true
   *
   * _.isEmpty(1);
   * // => true
   *
   * _.isEmpty([1, 2, 3]);
   * // => false
   *
   * _.isEmpty({ 'a': 1 });
   * // => false
   */
  function isEmpty(value) {
    if (value == null) {
      return true;
    }
    if (isArrayLike(value) &&
        (isArray(value) || typeof value == 'string' || typeof value.splice == 'function' ||
          isBuffer(value) || isTypedArray(value) || isArguments(value))) {
      return !value.length;
    }
    var tag = getTag(value);
    if (tag == mapTag || tag == setTag) {
      return !value.size;
    }
    if (isPrototype(value)) {
      return !baseKeys(value).length;
    }
    for (var key in value) {
      if (hasOwnProperty.call(value, key)) {
        return false;
      }
    }
    return true;
  }

  /**
   * Performs a deep comparison between two values to determine if they are
   * equivalent.
   *
   * **Note:** This method supports comparing arrays, array buffers, booleans,
   * date objects, error objects, maps, numbers, `Object` objects, regexes,
   * sets, strings, symbols, and typed arrays. `Object` objects are compared
   * by their own, not inherited, enumerable properties. Functions and DOM
   * nodes are compared by strict equality, i.e. `===`.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Lang
   * @param {*} value The value to compare.
   * @param {*} other The other value to compare.
   * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
   * @example
   *
   * var object = { 'a': 1 };
   * var other = { 'a': 1 };
   *
   * _.isEqual(object, other);
   * // => true
   *
   * object === other;
   * // => false
   */
  function isEqual(value, other) {
    return baseIsEqual(value, other);
  }

  /**
   * Checks if `value` is classified as a `Function` object.
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Lang
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is a function, else `false`.
   * @example
   *
   * _.isFunction(_);
   * // => true
   *
   * _.isFunction(/abc/);
   * // => false
   */
  function isFunction(value) {
    if (!isObject(value)) {
      return false;
    }
    // The use of `Object#toString` avoids issues with the `typeof` operator
    // in Safari 9 which returns 'object' for typed arrays and other constructors.
    var tag = baseGetTag(value);
    return tag == funcTag || tag == genTag || tag == asyncTag || tag == proxyTag;
  }

  /**
   * Checks if `value` is a valid array-like length.
   *
   * **Note:** This method is loosely based on
   * [`ToLength`](http://ecma-international.org/ecma-262/7.0/#sec-tolength).
   *
   * @static
   * @memberOf _
   * @since 4.0.0
   * @category Lang
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is a valid length, else `false`.
   * @example
   *
   * _.isLength(3);
   * // => true
   *
   * _.isLength(Number.MIN_VALUE);
   * // => false
   *
   * _.isLength(Infinity);
   * // => false
   *
   * _.isLength('3');
   * // => false
   */
  function isLength(value) {
    return typeof value == 'number' &&
      value > -1 && value % 1 == 0 && value <= MAX_SAFE_INTEGER;
  }

  /**
   * Checks if `value` is the
   * [language type](http://www.ecma-international.org/ecma-262/7.0/#sec-ecmascript-language-types)
   * of `Object`. (e.g. arrays, functions, objects, regexes, `new Number(0)`, and `new String('')`)
   *
   * @static
   * @memberOf _
   * @since 0.1.0
   * @category Lang
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is an object, else `false`.
   * @example
   *
   * _.isObject({});
   * // => true
   *
   * _.isObject([1, 2, 3]);
   * // => true
   *
   * _.isObject(_.noop);
   * // => true
   *
   * _.isObject(null);
   * // => false
   */
  function isObject(value) {
    var type = typeof value;
    return value != null && (type == 'object' || type == 'function');
  }

  /**
   * Checks if `value` is object-like. A value is object-like if it's not `null`
   * and has a `typeof` result of "object".
   *
   * @static
   * @memberOf _
   * @since 4.0.0
   * @category Lang
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is object-like, else `false`.
   * @example
   *
   * _.isObjectLike({});
   * // => true
   *
   * _.isObjectLike([1, 2, 3]);
   * // => true
   *
   * _.isObjectLike(_.noop);
   * // => false
   *
   * _.isObjectLike(null);
   * // => false
   */
  function isObjectLike(value) {
    return value != null && typeof value == 'object';
  }

  /**
   * Checks if `value` is classified as a `Map` object.
   *
   * @static
   * @memberOf _
   * @since 4.3.0
   * @category Lang
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is a map, else `false`.
   * @example
   *
   * _.isMap(new Map);
   * // => true
   *
   * _.isMap(new WeakMap);
   * // => false
   */
  var isMap = nodeIsMap ? baseUnary(nodeIsMap) : baseIsMap;

  /**
   * Checks if `value` is a plain object, that is, an object created by the
   * `Object` constructor or one with a `[[Prototype]]` of `null`.
   *
   * @static
   * @memberOf _
   * @since 0.8.0
   * @category Lang
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is a plain object, else `false`.
   * @example
   *
   * function Foo() {
   *   this.a = 1;
   * }
   *
   * _.isPlainObject(new Foo);
   * // => false
   *
   * _.isPlainObject([1, 2, 3]);
   * // => false
   *
   * _.isPlainObject({ 'x': 0, 'y': 0 });
   * // => true
   *
   * _.isPlainObject(Object.create(null));
   * // => true
   */
  function isPlainObject(value) {
    if (!isObjectLike(value) || baseGetTag(value) != objectTag) {
      return false;
    }
    var proto = getPrototype(value);
    if (proto === null) {
      return true;
    }
    var Ctor = hasOwnProperty.call(proto, 'constructor') && proto.constructor;
    return typeof Ctor == 'function' && Ctor instanceof Ctor &&
      funcToString.call(Ctor) == objectCtorString;
  }

  /**
   * Checks if `value` is classified as a `Set` object.
   *
   * @static
   * @memberOf _
   * @since 4.3.0
   * @category Lang
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is a set, else `false`.
   * @example
   *
   * _.isSet(new Set);
   * // => true
   *
   * _.isSet(new WeakSet);
   * // => false
   */
  var isSet = nodeIsSet ? baseUnary(nodeIsSet) : baseIsSet;

  /**
   * Checks if `value` is classified as a `String` primitive or object.
   *
   * @static
   * @since 0.1.0
   * @memberOf _
   * @category Lang
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is a string, else `false`.
   * @example
   *
   * _.isString('abc');
   * // => true
   *
   * _.isString(1);
   * // => false
   */
  function isString(value) {
    return typeof value == 'string' ||
      (!isArray(value) && isObjectLike(value) && baseGetTag(value) == stringTag);
  }

  /**
   * Checks if `value` is classified as a `Symbol` primitive or object.
   *
   * @static
   * @memberOf _
   * @since 4.0.0
   * @category Lang
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is a symbol, else `false`.
   * @example
   *
   * _.isSymbol(Symbol.iterator);
   * // => true
   *
   * _.isSymbol('abc');
   * // => false
   */
  function isSymbol(value) {
    return typeof value == 'symbol' ||
      (isObjectLike(value) && baseGetTag(value) == symbolTag);
  }

  /**
   * Checks if `value` is classified as a typed array.
   *
   * @static
   * @memberOf _
   * @since 3.0.0
   * @category Lang
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is a typed array, else `false`.
   * @example
   *
   * _.isTypedArray(new Uint8Array);
   * // => true
   *
   * _.isTypedArray([]);
   * // => false
   */
  var isTypedArray = nodeIsTypedArray ? baseUnary(nodeIsTypedArray) : baseIsTypedArray;

  /**
   * Converts `value` to an array.
   *
   * @static
   * @since 0.1.0
   * @memberOf _
   * @category Lang
   * @param {*} value The value to convert.
   * @returns {Array} Returns the converted array.
   * @example
   *
   * _.toArray({ 'a': 1, 'b': 2 });
   * // => [1, 2]
   *
   * _.toArray('abc');
   * // => ['a', 'b', 'c']
   *
   * _.toArray(1);
   * // => []
   *
   * _.toArray(null);
   * // => []
   */
  function toArray(value) {
    if (!value) {
      return [];
    }
    if (isArrayLike(value)) {
      return isString(value) ? stringToArray(value) : copyArray(value);
    }
    if (symIterator && value[symIterator]) {
      return iteratorToArray(value[symIterator]());
    }
    var tag = getTag(value),
        func = tag == mapTag ? mapToArray : (tag == setTag ? setToArray : values);

    return func(value);
  }

  /**
   * Converts `value` to a finite number.
   *
   * @static
   * @memberOf _
   * @since 4.12.0
   * @category Lang
   * @param {*} value The value to convert.
   * @returns {number} Returns the converted number.
   * @example
   *
   * _.toFinite(3.2);
   * // => 3.2
   *
   * _.toFinite(Number.MIN_VALUE);
   * // => 5e-324
   *
   * _.toFinite(Infinity);
   * // => 1.7976931348623157e+308
   *
   * _.toFinite('3.2');
   * // => 3.2
   */
  function toFinite(value) {
    if (!value) {
      return value === 0 ? value : 0;
    }
    value = toNumber(value);
    if (value === INFINITY || value === -INFINITY) {
      var sign = (value < 0 ? -1 : 1);
      return sign * MAX_INTEGER;
    }
    return value === value ? value : 0;
  }

  /**
   * Converts `value` to an integer.
   *
   * **Note:** This method is loosely based on
   * [`ToInteger`](http://www.ecma-international.org/ecma-262/7.0/#sec-tointeger).
   *
   * @static
   * @memberOf _
   * @since 4.0.0
   * @category Lang
   * @param {*} value The value to convert.
   * @returns {number} Returns the converted integer.
   * @example
   *
   * _.toInteger(3.2);
   * // => 3
   *
   * _.toInteger(Number.MIN_VALUE);
   * // => 0
   *
   * _.toInteger(Infinity);
   * // => 1.7976931348623157e+308
   *
   * _.toInteger('3.2');
   * // => 3
   */
  function toInteger(value) {
    var result = toFinite(value),
        remainder = result % 1;

    return result === result ? (remainder ? result - remainder : result) : 0;
  }

  /**
   * Converts `value` to a number.
   *
   * @static
   * @memberOf _
   * @since 4.0.0
   * @category Lang
   * @param {*} value The value to process.
   * @returns {number} Returns the number.
   * @example
   *
   * _.toNumber(3.2);
   * // => 3.2
   *
   * _.toNumber(Number.MIN_VALUE);
   * // => 5e-324
   *
   * _.toNumber(Infinity);
   * // => Infinity
   *
   * _.toNumber('3.2');
   * // => 3.2
   */
  function toNumber(value) {
    if (typeof value == 'number') {
      return value;
    }
    if (isSymbol(value)) {
      return NAN;
    }
    if (isObject(value)) {
      var other = typeof value.valueOf == 'function' ? value.valueOf() : value;
      value = isObject(other) ? (other + '') : other;
    }
    if (typeof value != 'string') {
      return value === 0 ? value : +value;
    }
    value = value.replace(reTrim, '');
    var isBinary = reIsBinary.test(value);
    return (isBinary || reIsOctal.test(value))
      ? freeParseInt(value.slice(2), isBinary ? 2 : 8)
      : (reIsBadHex.test(value) ? NAN : +value);
  }

  /**
   * Converts `value` to a plain object flattening inherited enumerable string
   * keyed properties of `value` to own properties of the plain object.
   *
   * @static
   * @memberOf _
   * @since 3.0.0
   * @category Lang
   * @param {*} value The value to convert.
   * @returns {Object} Returns the converted plain object.
   * @example
   *
   * function Foo() {
   *   this.b = 2;
   * }
   *
   * Foo.prototype.c = 3;
   *
   * _.assign({ 'a': 1 }, new Foo);
   * // => { 'a': 1, 'b': 2 }
   *
   * _.assign({ 'a': 1 }, _.toPlainObject(new Foo));
   * // => { 'a': 1, 'b': 2, 'c': 3 }
   */
  function toPlainObject(value) {
    return copyObject(value, keysIn(value));
  }

  /**
   * Converts `value` to a string. An empty string is returned for `null`
   * and `undefined` values. The sign of `-0` is preserved.
   *
   * @static
   * @memberOf _
   * @since 4.0.0
   * @category Lang
   * @param {*} value The value to convert.
   * @returns {string} Returns the converted string.
   * @example
   *
   * _.toString(null);
   * // => ''
   *
   * _.toString(-0);
   * // => '-0'
   *
   * _.toString([1, 2, 3]);
   * // => '1,2,3'
   */
  function toString(value) {
    return value == null ? '' : baseToString(value);
  }

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

  /**
   * This method is like `_.assign` except that it iterates over own and
   * inherited source properties.
   *
   * **Note:** This method mutates `object`.
   *
   * @static
   * @memberOf _
   * @since 4.0.0
   * @alias extend
   * @category Object
   * @param {Object} object The destination object.
   * @param {...Object} [sources] The source objects.
   * @returns {Object} Returns `object`.
   * @see _.assign
   * @example
   *
   * function Foo() {
   *   this.a = 1;
   * }
   *
   * function Bar() {
   *   this.c = 3;
   * }
   *
   * Foo.prototype.b = 2;
   * Bar.prototype.d = 4;
   *
   * _.assignIn({ 'a': 0 }, new Foo, new Bar);
   * // => { 'a': 1, 'b': 2, 'c': 3, 'd': 4 }
   */
  var assignIn = createAssigner(function(object, source) {
    copyObject(source, keysIn(source), object);
  });

  /**
   * Gets the value at `path` of `object`. If the resolved value is
   * `undefined`, the `defaultValue` is returned in its place.
   *
   * @static
   * @memberOf _
   * @since 3.7.0
   * @category Object
   * @param {Object} object The object to query.
   * @param {Array|string} path The path of the property to get.
   * @param {*} [defaultValue] The value returned for `undefined` resolved values.
   * @returns {*} Returns the resolved value.
   * @example
   *
   * var object = { 'a': [{ 'b': { 'c': 3 } }] };
   *
   * _.get(object, 'a[0].b.c');
   * // => 3
   *
   * _.get(object, ['a', '0', 'b', 'c']);
   * // => 3
   *
   * _.get(object, 'a.b.c', 'default');
   * // => 'default'
   */
  function get(object, path, defaultValue) {
    var result = object == null ? undefined : baseGet(object, path);
    return result === undefined ? defaultValue : result;
  }

  /**
   * Checks if `path` is a direct or inherited property of `object`.
   *
   * @static
   * @memberOf _
   * @since 4.0.0
   * @category Object
   * @param {Object} object The object to query.
   * @param {Array|string} path The path to check.
   * @returns {boolean} Returns `true` if `path` exists, else `false`.
   * @example
   *
   * var object = _.create({ 'a': _.create({ 'b': 2 }) });
   *
   * _.hasIn(object, 'a');
   * // => true
   *
   * _.hasIn(object, 'a.b');
   * // => true
   *
   * _.hasIn(object, ['a', 'b']);
   * // => true
   *
   * _.hasIn(object, 'b');
   * // => false
   */
  function hasIn(object, path) {
    return object != null && hasPath(object, path, baseHasIn);
  }

  /**
   * Invokes the method at `path` of `object`.
   *
   * @static
   * @memberOf _
   * @since 4.0.0
   * @category Object
   * @param {Object} object The object to query.
   * @param {Array|string} path The path of the method to invoke.
   * @param {...*} [args] The arguments to invoke the method with.
   * @returns {*} Returns the result of the invoked method.
   * @example
   *
   * var object = { 'a': [{ 'b': { 'c': [1, 2, 3, 4] } }] };
   *
   * _.invoke(object, 'a[0].b.c.slice', 1, 3);
   * // => [2, 3]
   */
  var invoke = baseRest(baseInvoke);

  /**
   * Creates an array of the own enumerable property names of `object`.
   *
   * **Note:** Non-object values are coerced to objects. See the
   * [ES spec](http://ecma-international.org/ecma-262/7.0/#sec-object.keys)
   * for more details.
   *
   * @static
   * @since 0.1.0
   * @memberOf _
   * @category Object
   * @param {Object} object The object to query.
   * @returns {Array} Returns the array of property names.
   * @example
   *
   * function Foo() {
   *   this.a = 1;
   *   this.b = 2;
   * }
   *
   * Foo.prototype.c = 3;
   *
   * _.keys(new Foo);
   * // => ['a', 'b'] (iteration order is not guaranteed)
   *
   * _.keys('hi');
   * // => ['0', '1']
   */
  function keys(object) {
    return isArrayLike(object) ? arrayLikeKeys(object) : baseKeys(object);
  }

  /**
   * Creates an array of the own and inherited enumerable property names of `object`.
   *
   * **Note:** Non-object values are coerced to objects.
   *
   * @static
   * @memberOf _
   * @since 3.0.0
   * @category Object
   * @param {Object} object The object to query.
   * @returns {Array} Returns the array of property names.
   * @example
   *
   * function Foo() {
   *   this.a = 1;
   *   this.b = 2;
   * }
   *
   * Foo.prototype.c = 3;
   *
   * _.keysIn(new Foo);
   * // => ['a', 'b', 'c'] (iteration order is not guaranteed)
   */
  function keysIn(object) {
    return isArrayLike(object) ? arrayLikeKeys(object, true) : baseKeysIn(object);
  }

  /**
   * This method is like `_.assign` except that it recursively merges own and
   * inherited enumerable string keyed properties of source objects into the
   * destination object. Source properties that resolve to `undefined` are
   * skipped if a destination value exists. Array and plain object properties
   * are merged recursively. Other objects and value types are overridden by
   * assignment. Source objects are applied from left to right. Subsequent
   * sources overwrite property assignments of previous sources.
   *
   * **Note:** This method mutates `object`.
   *
   * @static
   * @memberOf _
   * @since 0.5.0
   * @category Object
   * @param {Object} object The destination object.
   * @param {...Object} [sources] The source objects.
   * @returns {Object} Returns `object`.
   * @example
   *
   * var object = {
   *   'a': [{ 'b': 2 }, { 'd': 4 }]
   * };
   *
   * var other = {
   *   'a': [{ 'c': 3 }, { 'e': 5 }]
   * };
   *
   * _.merge(object, other);
   * // => { 'a': [{ 'b': 2, 'c': 3 }, { 'd': 4, 'e': 5 }] }
   */
  var merge = createAssigner(function(object, source, srcIndex) {
    baseMerge(object, source, srcIndex);
  });

  /**
   * The opposite of `_.pick`; this method creates an object composed of the
   * own and inherited enumerable property paths of `object` that are not omitted.
   *
   * **Note:** This method is considerably slower than `_.pick`.
   *
   * @static
   * @since 0.1.0
   * @memberOf _
   * @category Object
   * @param {Object} object The source object.
   * @param {...(string|string[])} [paths] The property paths to omit.
   * @returns {Object} Returns the new object.
   * @example
   *
   * var object = { 'a': 1, 'b': '2', 'c': 3 };
   *
   * _.omit(object, ['a', 'c']);
   * // => { 'b': '2' }
   */
  var omit = flatRest(function(object, paths) {
    var result = {};
    if (object == null) {
      return result;
    }
    var isDeep = false;
    paths = arrayMap(paths, function(path) {
      path = castPath(path, object);
      isDeep || (isDeep = path.length > 1);
      return path;
    });
    copyObject(object, getAllKeysIn(object), result);
    if (isDeep) {
      result = baseClone(result, CLONE_DEEP_FLAG | CLONE_FLAT_FLAG | CLONE_SYMBOLS_FLAG, customOmitClone);
    }
    var length = paths.length;
    while (length--) {
      baseUnset(result, paths[length]);
    }
    return result;
  });

  /**
   * Creates an object composed of the picked `object` properties.
   *
   * @static
   * @since 0.1.0
   * @memberOf _
   * @category Object
   * @param {Object} object The source object.
   * @param {...(string|string[])} [paths] The property paths to pick.
   * @returns {Object} Returns the new object.
   * @example
   *
   * var object = { 'a': 1, 'b': '2', 'c': 3 };
   *
   * _.pick(object, ['a', 'c']);
   * // => { 'a': 1, 'c': 3 }
   */
  var pick = flatRest(function(object, paths) {
    return object == null ? {} : basePick(object, paths);
  });

  /**
   * Creates an array of the own enumerable string keyed property values of `object`.
   *
   * **Note:** Non-object values are coerced to objects.
   *
   * @static
   * @since 0.1.0
   * @memberOf _
   * @category Object
   * @param {Object} object The object to query.
   * @returns {Array} Returns the array of property values.
   * @example
   *
   * function Foo() {
   *   this.a = 1;
   *   this.b = 2;
   * }
   *
   * Foo.prototype.c = 3;
   *
   * _.values(new Foo);
   * // => [1, 2] (iteration order is not guaranteed)
   *
   * _.values('hi');
   * // => ['h', 'i']
   */
  function values(object) {
    return object == null ? [] : baseValues(object, keys(object));
  }

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

  /**
   * Creates a function that returns `value`.
   *
   * @static
   * @memberOf _
   * @since 2.4.0
   * @category Util
   * @param {*} value The value to return from the new function.
   * @returns {Function} Returns the new constant function.
   * @example
   *
   * var objects = _.times(2, _.constant({ 'a': 1 }));
   *
   * console.log(objects);
   * // => [{ 'a': 1 }, { 'a': 1 }]
   *
   * console.log(objects[0] === objects[1]);
   * // => true
   */
  function constant(value) {
    return function() {
      return value;
    };
  }

  /**
   * This method returns the first argument it receives.
   *
   * @static
   * @since 0.1.0
   * @memberOf _
   * @category Util
   * @param {*} value Any value.
   * @returns {*} Returns `value`.
   * @example
   *
   * var object = { 'a': 1 };
   *
   * console.log(_.identity(object) === object);
   * // => true
   */
  function identity(value) {
    return value;
  }

  /**
   * Creates a function that invokes `func` with the arguments of the created
   * function. If `func` is a property name, the created function returns the
   * property value for a given element. If `func` is an array or object, the
   * created function returns `true` for elements that contain the equivalent
   * source properties, otherwise it returns `false`.
   *
   * @static
   * @since 4.0.0
   * @memberOf _
   * @category Util
   * @param {*} [func=_.identity] The value to convert to a callback.
   * @returns {Function} Returns the callback.
   * @example
   *
   * var users = [
   *   { 'user': 'barney', 'age': 36, 'active': true },
   *   { 'user': 'fred',   'age': 40, 'active': false }
   * ];
   *
   * // The `_.matches` iteratee shorthand.
   * _.filter(users, _.iteratee({ 'user': 'barney', 'active': true }));
   * // => [{ 'user': 'barney', 'age': 36, 'active': true }]
   *
   * // The `_.matchesProperty` iteratee shorthand.
   * _.filter(users, _.iteratee(['user', 'fred']));
   * // => [{ 'user': 'fred', 'age': 40 }]
   *
   * // The `_.property` iteratee shorthand.
   * _.map(users, _.iteratee('user'));
   * // => ['barney', 'fred']
   *
   * // Create custom iteratee shorthands.
   * _.iteratee = _.wrap(_.iteratee, function(iteratee, func) {
   *   return !_.isRegExp(func) ? iteratee(func) : function(string) {
   *     return func.test(string);
   *   };
   * });
   *
   * _.filter(['abc', 'def'], /ef/);
   * // => ['def']
   */
  function iteratee(func) {
    return baseIteratee(typeof func == 'function' ? func : baseClone(func, CLONE_DEEP_FLAG));
  }

  /**
   * Adds all own enumerable string keyed function properties of a source
   * object to the destination object. If `object` is a function, then methods
   * are added to its prototype as well.
   *
   * **Note:** Use `_.runInContext` to create a pristine `lodash` function to
   * avoid conflicts caused by modifying the original.
   *
   * @static
   * @since 0.1.0
   * @memberOf _
   * @category Util
   * @param {Function|Object} [object=lodash] The destination object.
   * @param {Object} source The object of functions to add.
   * @param {Object} [options={}] The options object.
   * @param {boolean} [options.chain=true] Specify whether mixins are chainable.
   * @returns {Function|Object} Returns `object`.
   * @example
   *
   * function vowels(string) {
   *   return _.filter(string, function(v) {
   *     return /[aeiou]/i.test(v);
   *   });
   * }
   *
   * _.mixin({ 'vowels': vowels });
   * _.vowels('fred');
   * // => ['e']
   *
   * _('fred').vowels().value();
   * // => ['e']
   *
   * _.mixin({ 'vowels': vowels }, { 'chain': false });
   * _('fred').vowels();
   * // => ['e']
   */
  function mixin(object, source, options) {
    var props = keys(source),
        methodNames = baseFunctions(source, props);

    if (options == null &&
        !(isObject(source) && (methodNames.length || !props.length))) {
      options = source;
      source = object;
      object = this;
      methodNames = baseFunctions(source, keys(source));
    }
    var chain = !(isObject(options) && 'chain' in options) || !!options.chain,
        isFunc = isFunction(object);

    arrayEach(methodNames, function(methodName) {
      var func = source[methodName];
      object[methodName] = func;
      if (isFunc) {
        object.prototype[methodName] = function() {
          var chainAll = this.__chain__;
          if (chain || chainAll) {
            var result = object(this.__wrapped__),
                actions = result.__actions__ = copyArray(this.__actions__);

            actions.push({ 'func': func, 'args': arguments, 'thisArg': object });
            result.__chain__ = chainAll;
            return result;
          }
          return func.apply(object, arrayPush([this.value()], arguments));
        };
      }
    });

    return object;
  }

  /**
   * This method returns `undefined`.
   *
   * @static
   * @memberOf _
   * @since 2.3.0
   * @category Util
   * @example
   *
   * _.times(2, _.noop);
   * // => [undefined, undefined]
   */
  function noop() {
    // No operation performed.
  }

  /**
   * Creates a function that returns the value at `path` of a given object.
   *
   * @static
   * @memberOf _
   * @since 2.4.0
   * @category Util
   * @param {Array|string} path The path of the property to get.
   * @returns {Function} Returns the new accessor function.
   * @example
   *
   * var objects = [
   *   { 'a': { 'b': 2 } },
   *   { 'a': { 'b': 1 } }
   * ];
   *
   * _.map(objects, _.property('a.b'));
   * // => [2, 1]
   *
   * _.map(_.sortBy(objects, _.property(['a', 'b'])), 'a.b');
   * // => [1, 2]
   */
  function property(path) {
    return isKey(path) ? baseProperty(toKey(path)) : basePropertyDeep(path);
  }

  /**
   * Creates an array of numbers (positive and/or negative) progressing from
   * `start` up to, but not including, `end`. A step of `-1` is used if a negative
   * `start` is specified without an `end` or `step`. If `end` is not specified,
   * it's set to `start` with `start` then set to `0`.
   *
   * **Note:** JavaScript follows the IEEE-754 standard for resolving
   * floating-point values which can produce unexpected results.
   *
   * @static
   * @since 0.1.0
   * @memberOf _
   * @category Util
   * @param {number} [start=0] The start of the range.
   * @param {number} end The end of the range.
   * @param {number} [step=1] The value to increment or decrement by.
   * @returns {Array} Returns the range of numbers.
   * @see _.inRange, _.rangeRight
   * @example
   *
   * _.range(4);
   * // => [0, 1, 2, 3]
   *
   * _.range(-4);
   * // => [0, -1, -2, -3]
   *
   * _.range(1, 5);
   * // => [1, 2, 3, 4]
   *
   * _.range(0, 20, 5);
   * // => [0, 5, 10, 15]
   *
   * _.range(0, -4, -1);
   * // => [0, -1, -2, -3]
   *
   * _.range(1, 4, 0);
   * // => [1, 1, 1]
   *
   * _.range(0);
   * // => []
   */
  var range = createRange();

  /**
   * This method returns a new empty array.
   *
   * @static
   * @memberOf _
   * @since 4.13.0
   * @category Util
   * @returns {Array} Returns the new empty array.
   * @example
   *
   * var arrays = _.times(2, _.stubArray);
   *
   * console.log(arrays);
   * // => [[], []]
   *
   * console.log(arrays[0] === arrays[1]);
   * // => false
   */
  function stubArray() {
    return [];
  }

  /**
   * This method returns `false`.
   *
   * @static
   * @memberOf _
   * @since 4.13.0
   * @category Util
   * @returns {boolean} Returns `false`.
   * @example
   *
   * _.times(2, _.stubFalse);
   * // => [false, false]
   */
  function stubFalse() {
    return false;
  }

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

  /**
   * Computes the maximum value of `array`. If `array` is empty or falsey,
   * `undefined` is returned.
   *
   * @static
   * @since 0.1.0
   * @memberOf _
   * @category Math
   * @param {Array} array The array to iterate over.
   * @returns {*} Returns the maximum value.
   * @example
   *
   * _.max([4, 2, 8, 6]);
   * // => 8
   *
   * _.max([]);
   * // => undefined
   */
  function max(array) {
    return (array && array.length)
      ? baseExtremum(array, identity, baseGt)
      : undefined;
  }

  /**
   * Computes the minimum value of `array`. If `array` is empty or falsey,
   * `undefined` is returned.
   *
   * @static
   * @since 0.1.0
   * @memberOf _
   * @category Math
   * @param {Array} array The array to iterate over.
   * @returns {*} Returns the minimum value.
   * @example
   *
   * _.min([4, 2, 8, 6]);
   * // => 2
   *
   * _.min([]);
   * // => undefined
   */
  function min(array) {
    return (array && array.length)
      ? baseExtremum(array, identity, baseLt)
      : undefined;
  }

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

  // Add methods that return wrapped values in chain sequences.
  lodash.assignIn = assignIn;
  lodash.chain = chain;
  lodash.compact = compact;
  lodash.constant = constant;
  lodash.debounce = debounce;
  lodash.delay = delay;
  lodash.filter = filter;
  lodash.flatten = flatten;
  lodash.groupBy = groupBy;
  lodash.intersection = intersection;
  lodash.iteratee = iteratee;
  lodash.keys = keys;
  lodash.keysIn = keysIn;
  lodash.map = map;
  lodash.memoize = memoize;
  lodash.merge = merge;
  lodash.mixin = mixin;
  lodash.negate = negate;
  lodash.omit = omit;
  lodash.pick = pick;
  lodash.property = property;
  lodash.range = range;
  lodash.reject = reject;
  lodash.reverse = reverse;
  lodash.sortBy = sortBy;
  lodash.tap = tap;
  lodash.throttle = throttle;
  lodash.thru = thru;
  lodash.toArray = toArray;
  lodash.toPlainObject = toPlainObject;
  lodash.union = union;
  lodash.uniq = uniq;
  lodash.values = values;
  lodash.without = without;

  // Add aliases.
  lodash.extend = assignIn;

  // Add methods to `lodash.prototype`.
  mixin(lodash, lodash);

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

  // Add methods that return unwrapped values in chain sequences.
  lodash.clone = clone;
  lodash.eq = eq;
  lodash.every = every;
  lodash.find = find;
  lodash.findIndex = findIndex;
  lodash.forEach = forEach;
  lodash.get = get;
  lodash.hasIn = hasIn;
  lodash.head = head;
  lodash.identity = identity;
  lodash.invoke = invoke;
  lodash.isArguments = isArguments;
  lodash.isArray = isArray;
  lodash.isArrayLike = isArrayLike;
  lodash.isArrayLikeObject = isArrayLikeObject;
  lodash.isBuffer = isBuffer;
  lodash.isEmpty = isEmpty;
  lodash.isEqual = isEqual;
  lodash.isFunction = isFunction;
  lodash.isLength = isLength;
  lodash.isMap = isMap;
  lodash.isObject = isObject;
  lodash.isObjectLike = isObjectLike;
  lodash.isPlainObject = isPlainObject;
  lodash.isSet = isSet;
  lodash.isString = isString;
  lodash.isSymbol = isSymbol;
  lodash.isTypedArray = isTypedArray;
  lodash.last = last;
  lodash.max = max;
  lodash.min = min;
  lodash.stubArray = stubArray;
  lodash.stubFalse = stubFalse;
  lodash.noop = noop;
  lodash.now = now;
  lodash.reduce = reduce;
  lodash.toFinite = toFinite;
  lodash.toInteger = toInteger;
  lodash.toNumber = toNumber;
  lodash.toString = toString;

  // Add aliases.
  lodash.each = forEach;
  lodash.first = head;

  mixin(lodash, (function() {
    var source = {};
    baseForOwn(lodash, function(func, methodName) {
      if (!hasOwnProperty.call(lodash.prototype, methodName)) {
        source[methodName] = func;
      }
    });
    return source;
  }()), { 'chain': false });

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

  /**
   * The semantic version number.
   *
   * @static
   * @memberOf _
   * @type {string}
   */
  lodash.VERSION = VERSION;

  // Add `LazyWrapper` methods for `_.drop` and `_.take` variants.
  arrayEach(['drop', 'take'], function(methodName, index) {
    LazyWrapper.prototype[methodName] = function(n) {
      n = n === undefined ? 1 : nativeMax(toInteger(n), 0);

      var result = (this.__filtered__ && !index)
        ? new LazyWrapper(this)
        : this.clone();

      if (result.__filtered__) {
        result.__takeCount__ = nativeMin(n, result.__takeCount__);
      } else {
        result.__views__.push({
          'size': nativeMin(n, MAX_ARRAY_LENGTH),
          'type': methodName + (result.__dir__ < 0 ? 'Right' : '')
        });
      }
      return result;
    };

    LazyWrapper.prototype[methodName + 'Right'] = function(n) {
      return this.reverse()[methodName](n).reverse();
    };
  });

  // Add `LazyWrapper` methods that accept an `iteratee` value.
  arrayEach(['filter', 'map', 'takeWhile'], function(methodName, index) {
    var type = index + 1,
        isFilter = type == LAZY_FILTER_FLAG || type == LAZY_WHILE_FLAG;

    LazyWrapper.prototype[methodName] = function(iteratee) {
      var result = this.clone();
      result.__iteratees__.push({
        'iteratee': getIteratee(iteratee, 3),
        'type': type
      });
      result.__filtered__ = result.__filtered__ || isFilter;
      return result;
    };
  });

  // Add `LazyWrapper` methods for `_.head` and `_.last`.
  arrayEach(['head', 'last'], function(methodName, index) {
    var takeName = 'take' + (index ? 'Right' : '');

    LazyWrapper.prototype[methodName] = function() {
      return this[takeName](1).value()[0];
    };
  });

  // Add `LazyWrapper` methods for `_.initial` and `_.tail`.
  arrayEach(['initial', 'tail'], function(methodName, index) {
    var dropName = 'drop' + (index ? '' : 'Right');

    LazyWrapper.prototype[methodName] = function() {
      return this.__filtered__ ? new LazyWrapper(this) : this[dropName](1);
    };
  });

  LazyWrapper.prototype.compact = function() {
    return this.filter(identity);
  };

  LazyWrapper.prototype.find = function(predicate) {
    return this.filter(predicate).head();
  };

  LazyWrapper.prototype.findLast = function(predicate) {
    return this.reverse().find(predicate);
  };

  LazyWrapper.prototype.invokeMap = baseRest(function(path, args) {
    if (typeof path == 'function') {
      return new LazyWrapper(this);
    }
    return this.map(function(value) {
      return baseInvoke(value, path, args);
    });
  });

  LazyWrapper.prototype.reject = function(predicate) {
    return this.filter(negate(getIteratee(predicate)));
  };

  LazyWrapper.prototype.slice = function(start, end) {
    start = toInteger(start);

    var result = this;
    if (result.__filtered__ && (start > 0 || end < 0)) {
      return new LazyWrapper(result);
    }
    if (start < 0) {
      result = result.takeRight(-start);
    } else if (start) {
      result = result.drop(start);
    }
    if (end !== undefined) {
      end = toInteger(end);
      result = end < 0 ? result.dropRight(-end) : result.take(end - start);
    }
    return result;
  };

  LazyWrapper.prototype.takeRightWhile = function(predicate) {
    return this.reverse().takeWhile(predicate).reverse();
  };

  LazyWrapper.prototype.toArray = function() {
    return this.take(MAX_ARRAY_LENGTH);
  };

  // Add `LazyWrapper` methods to `lodash.prototype`.
  baseForOwn(LazyWrapper.prototype, function(func, methodName) {
    var checkIteratee = /^(?:filter|find|map|reject)|While$/.test(methodName),
        isTaker = /^(?:head|last)$/.test(methodName),
        lodashFunc = lodash[isTaker ? ('take' + (methodName == 'last' ? 'Right' : '')) : methodName],
        retUnwrapped = isTaker || /^find/.test(methodName);

    if (!lodashFunc) {
      return;
    }
    lodash.prototype[methodName] = function() {
      var value = this.__wrapped__,
          args = isTaker ? [1] : arguments,
          isLazy = value instanceof LazyWrapper,
          iteratee = args[0],
          useLazy = isLazy || isArray(value);

      var interceptor = function(value) {
        var result = lodashFunc.apply(lodash, arrayPush([value], args));
        return (isTaker && chainAll) ? result[0] : result;
      };

      if (useLazy && checkIteratee && typeof iteratee == 'function' && iteratee.length != 1) {
        // Avoid lazy use if the iteratee has a "length" value other than `1`.
        isLazy = useLazy = false;
      }
      var chainAll = this.__chain__,
          isHybrid = !!this.__actions__.length,
          isUnwrapped = retUnwrapped && !chainAll,
          onlyLazy = isLazy && !isHybrid;

      if (!retUnwrapped && useLazy) {
        value = onlyLazy ? value : new LazyWrapper(this);
        var result = func.apply(value, args);
        result.__actions__.push({ 'func': thru, 'args': [interceptor], 'thisArg': undefined });
        return new LodashWrapper(result, chainAll);
      }
      if (isUnwrapped && onlyLazy) {
        return func.apply(this, args);
      }
      result = this.thru(interceptor);
      return isUnwrapped ? (isTaker ? result.value()[0] : result.value()) : result;
    };
  });

  // Add `Array` methods to `lodash.prototype`.
  arrayEach(['pop', 'push', 'shift', 'sort', 'splice', 'unshift'], function(methodName) {
    var func = arrayProto[methodName],
        chainName = /^(?:push|sort|unshift)$/.test(methodName) ? 'tap' : 'thru',
        retUnwrapped = /^(?:pop|shift)$/.test(methodName);

    lodash.prototype[methodName] = function() {
      var args = arguments;
      if (retUnwrapped && !this.__chain__) {
        var value = this.value();
        return func.apply(isArray(value) ? value : [], args);
      }
      return this[chainName](function(value) {
        return func.apply(isArray(value) ? value : [], args);
      });
    };
  });

  // Map minified method names to their real names.
  baseForOwn(LazyWrapper.prototype, function(func, methodName) {
    var lodashFunc = lodash[methodName];
    if (lodashFunc) {
      var key = lodashFunc.name + '';
      if (!hasOwnProperty.call(realNames, key)) {
        realNames[key] = [];
      }
      realNames[key].push({ 'name': methodName, 'func': lodashFunc });
    }
  });

  realNames[createHybrid(undefined, WRAP_BIND_KEY_FLAG).name] = [{
    'name': 'wrapper',
    'func': undefined
  }];

  // Add methods to `LazyWrapper`.
  LazyWrapper.prototype.clone = lazyClone;
  LazyWrapper.prototype.reverse = lazyReverse;
  LazyWrapper.prototype.value = lazyValue;

  // Add chain sequence methods to the `lodash` wrapper.
  lodash.prototype.chain = wrapperChain;
  lodash.prototype.commit = wrapperCommit;
  lodash.prototype.next = wrapperNext;
  lodash.prototype.plant = wrapperPlant;
  lodash.prototype.reverse = wrapperReverse;
  lodash.prototype.toJSON = lodash.prototype.valueOf = lodash.prototype.value = wrapperValue;

  // Add lazy aliases.
  lodash.prototype.first = lodash.prototype.head;

  if (symIterator) {
    lodash.prototype[symIterator] = wrapperToIterator;
  }

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

  // Some AMD build optimizers, like r.js, check for condition patterns like:
  if (typeof define == 'function' && typeof define.amd == 'object' && define.amd) {
    // Expose Lodash on the global object to prevent errors when Lodash is
    // loaded by a script tag in the presence of an AMD loader.
    // See http://requirejs.org/docs/errors.html#mismatch for more details.
    // Use `_.noConflict` to remove Lodash from the global object.
    root._ = 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 it.
  else if (freeModule) {
    // Export for Node.js.
    (freeModule.exports = lodash)._ = lodash;
    // Export for CommonJS support.
    freeExports._ = lodash;
  }
  else {
    // Export to the global object.
    root._ = lodash;
  }
}.call(this));