lodash/lodash._baseiteratee/index.js

/**
 * lodash 4.4.0 (Custom Build) <https://lodash.com/>
 * Build: `lodash modularize exports="npm" -o ./`
 * Copyright 2012-2016 The Dojo Foundation <http://dojofoundation.org/>
 * Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
 * Copyright 2009-2016 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 * Available under MIT license <https://lodash.com/license>
 */
var Stack = require('lodash._stack'),
    baseSlice = require('lodash._baseslice'),
    root = require('lodash._root'),
    toString = require('lodash.tostring');

/** Used to compose bitmasks for comparison styles. */
var UNORDERED_COMPARE_FLAG = 1,
    PARTIAL_COMPARE_FLAG = 2;

/** Used as references for various `Number` constants. */
var MAX_SAFE_INTEGER = 9007199254740991;

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

var arrayBufferTag = '[object ArrayBuffer]',
    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-262/6.0/#sec-patterns). */
var reRegExpChar = /[\\^$.*+?()[\]{}|]/g;

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

/** Used to detect host constructors (Safari > 5). */
var reIsHostCtor = /^\[object .+?Constructor\]$/;

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

/** 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[dateTag] = typedArrayTags[errorTag] =
typedArrayTags[funcTag] = typedArrayTags[mapTag] =
typedArrayTags[numberTag] = typedArrayTags[objectTag] =
typedArrayTags[regexpTag] = typedArrayTags[setTag] =
typedArrayTags[stringTag] = typedArrayTags[weakMapTag] = 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.length,
      result = Array(length);

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

/**
 * 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.length;

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

/**
 * 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 `_.toPairs` and `_.toPairsIn` which creates an array
 * of key-value pairs for `object` corresponding to the property names of `props`.
 *
 * @private
 * @param {Object} object The object to query.
 * @param {Array} props The property names to get values for.
 * @returns {Object} Returns the new array of key-value pairs.
 */
function baseToPairs(object, props) {
  return arrayMap(props, function(key) {
    return [key, object[key]];
  });
}

/**
 * Checks if `value` is a host object in IE < 9.
 *
 * @private
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is a host object, else `false`.
 */
function isHostObject(value) {
  // Many host objects are `Object` objects that can coerce to strings
  // despite having improperly defined `toString` methods.
  var result = false;
  if (value != null && typeof value.toString != 'function') {
    try {
      result = !!(value + '');
    } catch (e) {}
  }
  return result;
}

/**
 * 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) {
  value = (typeof value == 'number' || reIsUint.test(value)) ? +value : -1;
  length = length == null ? MAX_SAFE_INTEGER : length;
  return value > -1 && value % 1 == 0 && value < length;
}

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

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

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

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

/** Used for built-in method references. */
var objectProto = Object.prototype;

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

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

/**
 * Used to resolve the [`toStringTag`](http://ecma-international.org/ecma-262/6.0/#sec-object.prototype.tostring)
 * of values.
 */
var objectToString = objectProto.toString;

/** 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 Symbol = root.Symbol,
    Uint8Array = root.Uint8Array,
    getPrototypeOf = Object.getPrototypeOf,
    propertyIsEnumerable = objectProto.propertyIsEnumerable;

/* Built-in method references for those with the same name as other `lodash` methods. */
var nativeKeys = Object.keys;

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

/** Used to detect maps, sets, and weakmaps. */
var mapCtorString = Map ? funcToString.call(Map) : '',
    setCtorString = Set ? funcToString.call(Set) : '',
    weakMapCtorString = WeakMap ? funcToString.call(WeakMap) : '';

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

/**
 * Casts `value` to a path array if it's not one.
 *
 * @private
 * @param {*} value The value to inspect.
 * @returns {Array} Returns the cast property path array.
 */
function baseCastPath(value) {
  return isArray(value) ? value : stringToPath(value);
}

/**
 * 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 = isKey(path, object) ? [path + ''] : baseCastPath(path);

  var index = 0,
      length = path.length;

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

/**
 * The base implementation of `_.has` without support for deep paths.
 *
 * @private
 * @param {Object} object The object to query.
 * @param {Array|string} key The key to check.
 * @returns {boolean} Returns `true` if `key` exists, else `false`.
 */
function baseHas(object, key) {
  // Avoid a bug in IE 10-11 where objects with a [[Prototype]] of `null`,
  // that are composed entirely of index properties, return `false` for
  // `hasOwnProperty` checks of them.
  return hasOwnProperty.call(object, key) ||
    (typeof object == 'object' && key in object && getPrototypeOf(object) === null);
}

/**
 * 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 key in Object(object);
}

/**
 * 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 {Function} [customizer] The function to customize comparisons.
 * @param {boolean} [bitmask] The bitmask of comparison flags.
 *  The bitmask may be composed of the following flags:
 *     1 - Unordered comparison
 *     2 - Partial comparison
 * @param {Object} [stack] Tracks traversed `value` and `other` objects.
 * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
 */
function baseIsEqual(value, other, customizer, bitmask, stack) {
  if (value === other) {
    return true;
  }
  if (value == null || other == null || (!isObject(value) && !isObjectLike(other))) {
    return value !== value && other !== other;
  }
  return baseIsEqualDeep(value, other, baseIsEqual, customizer, bitmask, 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 {Function} equalFunc The function to determine equivalents of values.
 * @param {Function} [customizer] The function to customize comparisons.
 * @param {number} [bitmask] The bitmask of comparison flags. See `baseIsEqual` for more details.
 * @param {Object} [stack] Tracks traversed `object` and `other` objects.
 * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
 */
function baseIsEqualDeep(object, other, equalFunc, customizer, bitmask, stack) {
  var objIsArr = isArray(object),
      othIsArr = isArray(other),
      objTag = arrayTag,
      othTag = arrayTag;

  if (!objIsArr) {
    objTag = getTag(object);
    if (objTag == argsTag) {
      objTag = objectTag;
    } else if (objTag != objectTag) {
      objIsArr = isTypedArray(object);
    }
  }
  if (!othIsArr) {
    othTag = getTag(other);
    if (othTag == argsTag) {
      othTag = objectTag;
    } else if (othTag != objectTag) {
      othIsArr = isTypedArray(other);
    }
  }
  var objIsObj = objTag == objectTag && !isHostObject(object),
      othIsObj = othTag == objectTag && !isHostObject(other),
      isSameTag = objTag == othTag;

  if (isSameTag && !(objIsArr || objIsObj)) {
    return equalByTag(object, other, objTag, equalFunc, customizer, bitmask);
  }
  var isPartial = bitmask & PARTIAL_COMPARE_FLAG;
  if (!isPartial) {
    var objIsWrapped = objIsObj && hasOwnProperty.call(object, '__wrapped__'),
        othIsWrapped = othIsObj && hasOwnProperty.call(other, '__wrapped__');

    if (objIsWrapped || othIsWrapped) {
      return equalFunc(objIsWrapped ? object.value() : object, othIsWrapped ? other.value() : other, customizer, bitmask, stack);
    }
  }
  if (!isSameTag) {
    return false;
  }
  stack || (stack = new Stack);
  return (objIsArr ? equalArrays : equalObjects)(object, other, equalFunc, customizer, bitmask, stack);
}

/**
 * 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,
          result = customizer ? customizer(objValue, srcValue, key, object, source, stack) : undefined;

      if (!(result === undefined
            ? baseIsEqual(srcValue, objValue, customizer, UNORDERED_COMPARE_FLAG | PARTIAL_COMPARE_FLAG, stack)
            : result
          )) {
        return false;
      }
    }
  }
  return true;
}

/**
 * The base implementation of `_.iteratee`.
 *
 * @private
 * @param {*} [value=_.identity] The value to convert to an iteratee.
 * @returns {Function} Returns the iteratee.
 */
function baseIteratee(value) {
  var type = typeof value;
  if (type == 'function') {
    return value;
  }
  if (value == null) {
    return identity;
  }
  if (type == 'object') {
    return isArray(value)
      ? baseMatchesProperty(value[0], value[1])
      : baseMatches(value);
  }
  return property(value);
}

/**
 * The base implementation of `_.keys` which doesn't skip the constructor
 * property of prototypes or treat sparse arrays as dense.
 *
 * @private
 * @param {Object} object The object to query.
 * @returns {Array} Returns the array of property names.
 */
function baseKeys(object) {
  return nativeKeys(Object(object));
}

/**
 * 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 function.
 */
function baseMatches(source) {
  var matchData = getMatchData(source);
  if (matchData.length == 1 && matchData[0][2]) {
    var key = matchData[0][0],
        value = matchData[0][1];

    return function(object) {
      if (object == null) {
        return false;
      }
      return object[key] === value &&
        (value !== undefined || (key in Object(object)));
    };
  }
  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 function.
 */
function baseMatchesProperty(path, srcValue) {
  return function(object) {
    var objValue = get(object, path);
    return (objValue === undefined && objValue === srcValue)
      ? hasIn(object, path)
      : baseIsEqual(srcValue, objValue, undefined, UNORDERED_COMPARE_FLAG | PARTIAL_COMPARE_FLAG);
  };
}

/**
 * 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 function.
 */
function baseProperty(key) {
  return function(object) {
    return object == null ? undefined : object[key];
  };
}

/**
 * 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 function.
 */
function basePropertyDeep(path) {
  return function(object) {
    return baseGet(object, path);
  };
}

/**
 * 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 {Function} equalFunc The function to determine equivalents of values.
 * @param {Function} [customizer] The function to customize comparisons.
 * @param {number} [bitmask] The bitmask of comparison flags. See `baseIsEqual` for more details.
 * @param {Object} [stack] Tracks traversed `array` and `other` objects.
 * @returns {boolean} Returns `true` if the arrays are equivalent, else `false`.
 */
function equalArrays(array, other, equalFunc, customizer, bitmask, stack) {
  var index = -1,
      isPartial = bitmask & PARTIAL_COMPARE_FLAG,
      isUnordered = bitmask & UNORDERED_COMPARE_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) {
    return stacked == other;
  }
  var result = true;
  stack.set(array, other);

  // 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 (isUnordered) {
      if (!arraySome(other, function(othValue) {
            return arrValue === othValue || equalFunc(arrValue, othValue, customizer, bitmask, stack);
          })) {
        result = false;
        break;
      }
    } else if (!(arrValue === othValue || equalFunc(arrValue, othValue, customizer, bitmask, stack))) {
      result = false;
      break;
    }
  }
  stack['delete'](array);
  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 {Function} equalFunc The function to determine equivalents of values.
 * @param {Function} [customizer] The function to customize comparisons.
 * @param {number} [bitmask] The bitmask of comparison flags. See `baseIsEqual` for more details.
 * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
 */
function equalByTag(object, other, tag, equalFunc, customizer, bitmask) {
  switch (tag) {
    case arrayBufferTag:
      if ((object.byteLength != other.byteLength) ||
          !equalFunc(new Uint8Array(object), new Uint8Array(other))) {
        return false;
      }
      return true;

    case boolTag:
    case dateTag:
      // Coerce dates and booleans to numbers, dates to milliseconds and booleans
      // to `1` or `0` treating invalid dates coerced to `NaN` as not equal.
      return +object == +other;

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

    case numberTag:
      // Treat `NaN` vs. `NaN` as equal.
      return (object != +object) ? other != +other : object == +other;

    case regexpTag:
    case stringTag:
      // Coerce regexes to strings and treat strings primitives and string
      // objects as equal. See https://es5.github.io/#x15.10.6.4 for more details.
      return object == (other + '');

    case mapTag:
      var convert = mapToArray;

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

      // Recursively compare objects (susceptible to call stack limits).
      return (isPartial || object.size == other.size) &&
        equalFunc(convert(object), convert(other), customizer, bitmask | UNORDERED_COMPARE_FLAG);

    case symbolTag:
      return !!Symbol && (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 {Function} equalFunc The function to determine equivalents of values.
 * @param {Function} [customizer] The function to customize comparisons.
 * @param {number} [bitmask] The bitmask of comparison flags. See `baseIsEqual` for more details.
 * @param {Object} [stack] Tracks traversed `object` and `other` objects.
 * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
 */
function equalObjects(object, other, equalFunc, customizer, bitmask, stack) {
  var isPartial = bitmask & PARTIAL_COMPARE_FLAG,
      objProps = keys(object),
      objLength = objProps.length,
      othProps = keys(other),
      othLength = othProps.length;

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

  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, customizer, bitmask, 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);
  return result;
}

/**
 * Gets the "length" property value of `object`.
 *
 * **Note:** This function is used to avoid a [JIT bug](https://bugs.webkit.org/show_bug.cgi?id=142792)
 * that affects Safari on at least iOS 8.1-8.3 ARM64.
 *
 * @private
 * @param {Object} object The object to query.
 * @returns {*} Returns the "length" value.
 */
var getLength = baseProperty('length');

/**
 * 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 = toPairs(object),
      length = result.length;

  while (length--) {
    result[length][2] = isStrictComparable(result[length][1]);
  }
  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 = object == null ? undefined : object[key];
  return isNative(value) ? value : undefined;
}

/**
 * Gets the `toStringTag` of `value`.
 *
 * @private
 * @param {*} value The value to query.
 * @returns {string} Returns the `toStringTag`.
 */
function getTag(value) {
  return objectToString.call(value);
}

// Fallback for IE 11 providing `toStringTag` values for maps, sets, and weakmaps.
if ((Map && getTag(new Map) != mapTag) ||
    (Set && getTag(new Set) != setTag) ||
    (WeakMap && getTag(new WeakMap) != weakMapTag)) {
  getTag = function(value) {
    var result = objectToString.call(value),
        Ctor = result == objectTag ? value.constructor : null,
        ctorString = typeof Ctor == 'function' ? funcToString.call(Ctor) : '';

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

/**
 * 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) {
  if (object == null) {
    return false;
  }
  var result = hasFunc(object, path);
  if (!result && !isKey(path)) {
    path = baseCastPath(path);
    object = parent(object, path);
    if (object != null) {
      path = last(path);
      result = hasFunc(object, path);
    }
  }
  var length = object ? object.length : undefined;
  return result || (
    !!length && isLength(length) && isIndex(path, length) &&
    (isArray(object) || isString(object) || isArguments(object))
  );
}

/**
 * Creates an array of index keys for `object` values of arrays,
 * `arguments` objects, and strings, otherwise `null` is returned.
 *
 * @private
 * @param {Object} object The object to query.
 * @returns {Array|null} Returns index keys, else `null`.
 */
function indexKeys(object) {
  var length = object ? object.length : undefined;
  if (isLength(length) &&
      (isArray(object) || isString(object) || isArguments(object))) {
    return baseTimes(length, String);
  }
  return null;
}

/**
 * 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 (typeof value == 'number') {
    return true;
  }
  return !isArray(value) &&
    (reIsPlainProp.test(value) || !reIsDeepProp.test(value) ||
      (object != null && value in Object(object)));
}

/**
 * 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);
}

/**
 * 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 == 1 ? object : get(object, baseSlice(path, 0, -1));
}

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

/**
 * Gets the last element of `array`.
 *
 * @static
 * @memberOf _
 * @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 ? array.length : 0;
  return length ? array[length - 1] : undefined;
}

/**
 * Checks if `value` is likely an `arguments` object.
 *
 * @static
 * @memberOf _
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
 * @example
 *
 * _.isArguments(function() { return arguments; }());
 * // => true
 *
 * _.isArguments([1, 2, 3]);
 * // => false
 */
function isArguments(value) {
  // Safari 8.1 incorrectly makes `arguments.callee` enumerable in strict mode.
  return isArrayLikeObject(value) && hasOwnProperty.call(value, 'callee') &&
    (!propertyIsEnumerable.call(value, 'callee') || objectToString.call(value) == argsTag);
}

/**
 * Checks if `value` is classified as an `Array` object.
 *
 * @static
 * @memberOf _
 * @type {Function}
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is correctly classified, 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 _
 * @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 &&
    !(typeof value == 'function' && isFunction(value)) && isLength(getLength(value));
}

/**
 * This method is like `_.isArrayLike` except that it also checks if `value`
 * is an object.
 *
 * @static
 * @memberOf _
 * @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 classified as a `Function` object.
 *
 * @static
 * @memberOf _
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
 * @example
 *
 * _.isFunction(_);
 * // => true
 *
 * _.isFunction(/abc/);
 * // => false
 */
function isFunction(value) {
  // The use of `Object#toString` avoids issues with the `typeof` operator
  // in Safari 8 which returns 'object' for typed array constructors, and
  // PhantomJS 1.9 which returns 'function' for `NodeList` instances.
  var tag = isObject(value) ? objectToString.call(value) : '';
  return tag == funcTag || tag == genTag;
}

/**
 * Checks if `value` is a valid array-like length.
 *
 * **Note:** This function is loosely based on [`ToLength`](http://ecma-international.org/ecma-262/6.0/#sec-tolength).
 *
 * @static
 * @memberOf _
 * @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](https://es5.github.io/#x8) of `Object`.
 * (e.g. arrays, functions, objects, regexes, `new Number(0)`, and `new String('')`)
 *
 * @static
 * @memberOf _
 * @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 && (type == 'object' || type == 'function');
}

/**
 * Checks if `value` is object-like. A value is object-like if it's not `null`
 * and has a `typeof` result of "object".
 *
 * @static
 * @memberOf _
 * @category 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 && typeof value == 'object';
}

/**
 * Checks if `value` is a native function.
 *
 * @static
 * @memberOf _
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is a native function, else `false`.
 * @example
 *
 * _.isNative(Array.prototype.push);
 * // => true
 *
 * _.isNative(_);
 * // => false
 */
function isNative(value) {
  if (value == null) {
    return false;
  }
  if (isFunction(value)) {
    return reIsNative.test(funcToString.call(value));
  }
  return isObjectLike(value) &&
    (isHostObject(value) ? reIsNative : reIsHostCtor).test(value);
}

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

/**
 * Checks if `value` is classified as a typed array.
 *
 * @static
 * @memberOf _
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
 * @example
 *
 * _.isTypedArray(new Uint8Array);
 * // => true
 *
 * _.isTypedArray([]);
 * // => false
 */
function isTypedArray(value) {
  return isObjectLike(value) &&
    isLength(value.length) && !!typedArrayTags[objectToString.call(value)];
}

/**
 * Gets the value at `path` of `object`. If the resolved value is
 * `undefined` the `defaultValue` is used in its place.
 *
 * @static
 * @memberOf _
 * @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 if the resolved value is `undefined`.
 * @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 _
 * @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': _.create({ 'c': 3 }) }) });
 *
 * _.hasIn(object, 'a');
 * // => true
 *
 * _.hasIn(object, 'a.b.c');
 * // => true
 *
 * _.hasIn(object, ['a', 'b', 'c']);
 * // => true
 *
 * _.hasIn(object, 'b');
 * // => false
 */
function hasIn(object, path) {
  return hasPath(object, path, baseHasIn);
}

/**
 * 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-262/6.0/#sec-object.keys)
 * for more details.
 *
 * @static
 * @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) {
  var isProto = isPrototype(object);
  if (!(isProto || isArrayLike(object))) {
    return baseKeys(object);
  }
  var indexes = indexKeys(object),
      skipIndexes = !!indexes,
      result = indexes || [],
      length = result.length;

  for (var key in object) {
    if (baseHas(object, key) &&
        !(skipIndexes && (key == 'length' || isIndex(key, length))) &&
        !(isProto && key == 'constructor')) {
      result.push(key);
    }
  }
  return result;
}

/**
 * Creates an array of own enumerable key-value pairs for `object` which
 * can be consumed by `_.fromPairs`.
 *
 * @static
 * @memberOf _
 * @category Object
 * @param {Object} object The object to query.
 * @returns {Array} Returns the new array of key-value pairs.
 * @example
 *
 * function Foo() {
 *   this.a = 1;
 *   this.b = 2;
 * }
 *
 * Foo.prototype.c = 3;
 *
 * _.toPairs(new Foo);
 * // => [['a', 1], ['b', 2]] (iteration order is not guaranteed)
 */
function toPairs(object) {
  return baseToPairs(object, keys(object));
}

/**
 * This method returns the first argument given to it.
 *
 * @static
 * @memberOf _
 * @category Util
 * @param {*} value Any value.
 * @returns {*} Returns `value`.
 * @example
 *
 * var object = { 'user': 'fred' };
 *
 * _.identity(object) === object;
 * // => true
 */
function identity(value) {
  return value;
}

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

module.exports = baseIteratee;