Bump to v3.8.0.

README.md

@@ -1,4 +1,4 @@
-# lodash v3.6.0
+# lodash v3.8.0
 
 The [modern build](https://github.com/lodash/lodash/wiki/Build-Differences) of [lodash](https://lodash.com/) exported as [Node.js](http://nodejs.org/)/[io.js](https://iojs.org/) modules.
 
@@ -28,7 +28,7 @@ var array = require('lodash/array');
 var chunk = require('lodash/array/chunk');
 ```
 
-See the [package source](https://github.com/lodash/lodash/tree/3.6.0-npm) for more details.
+See the [package source](https://github.com/lodash/lodash/tree/3.8.0-npm) for more details.
 
 **Note:**<br>
 Don’t assign values to the [special variable](http://nodejs.org/api/repl.html#repl_repl_features) `_` when in the REPL.<br>
@@ -39,8 +39,8 @@ Install [n_](https://www.npmjs.com/package/n_) for a REPL that includes lodash b
 lodash is also available in a variety of other builds & module formats.
 
  * npm packages for [modern](https://www.npmjs.com/package/lodash), [compatibility](https://www.npmjs.com/package/lodash-compat), & [per method](https://www.npmjs.com/browse/keyword/lodash-modularized) builds
- * AMD modules for [modern](https://github.com/lodash/lodash/tree/3.6.0-amd) & [compatibility](https://github.com/lodash/lodash-compat/tree/3.6.0-amd) builds
+ * AMD modules for [modern](https://github.com/lodash/lodash/tree/3.8.0-amd) & [compatibility](https://github.com/lodash/lodash-compat/tree/3.8.0-amd) builds
- * ES modules for the [modern](https://github.com/lodash/lodash/tree/3.6.0-es) build
+ * ES modules for the [modern](https://github.com/lodash/lodash/tree/3.8.0-es) build
 
 ## Further Reading
 
@@ -66,7 +66,6 @@ lodash is also available in a variety of other builds & module formats.
  * [_.chunk](https://lodash.com/docs#chunk) for splitting an array into chunks of a given size
  * [_.clone](https://lodash.com/docs#clone) supports shallow cloning of `Date` & `RegExp` objects
  * [_.cloneDeep](https://lodash.com/docs#cloneDeep) for deep cloning arrays & objects
- * [_.create](https://lodash.com/docs#create) for easier object inheritance
  * [_.curry](https://lodash.com/docs#curry) & [_.curryRight](https://lodash.com/docs#curryRight) for creating [curried](http://hughfdjackson.com/javascript/why-curry-helps/) functions
  * [_.debounce](https://lodash.com/docs#debounce) & [_.throttle](https://lodash.com/docs#throttle) are cancelable & accept options for more control
  * [_.fill](https://lodash.com/docs#fill) to fill arrays with values
@@ -75,12 +74,15 @@ lodash is also available in a variety of other builds & module formats.
  * [_.forEach](https://lodash.com/docs#forEach) supports exiting early
  * [_.forIn](https://lodash.com/docs#forIn) for iterating all enumerable properties
  * [_.forOwn](https://lodash.com/docs#forOwn) for iterating own properties
+ * [_.get](https://lodash.com/docs#get) & [_.set](https://lodash.com/docs#set) for deep property getting & setting
  * [_.inRange](https://lodash.com/docs#inRange) for checking whether a number is within a given range
  * [_.isNative](https://lodash.com/docs#isNative) to check for native functions
  * [_.isPlainObject](https://lodash.com/docs#isPlainObject) & [_.toPlainObject](https://lodash.com/docs#toPlainObject) to check for & convert to `Object` objects
  * [_.isTypedArray](https://lodash.com/docs#isTypedArray) to check for typed arrays
+ * [_.mapKeys](https://lodash.com/docs#mapKeys) for mapping keys to an object
  * [_.matches](https://lodash.com/docs#matches) supports deep object comparisons
  * [_.matchesProperty](https://lodash.com/docs#matchesProperty) to complement [_.matches](https://lodash.com/docs#matches) & [_.property](https://lodash.com/docs#property)
+ * [_.method](https://lodash.com/docs#method) & [_.methodOf](https://lodash.com/docs#methodOf) to create functions that invoke methods
  * [_.merge](https://lodash.com/docs#merge) for a deep [_.extend](https://lodash.com/docs#extend)
  * [_.parseInt](https://lodash.com/docs#parseInt) for consistent cross-environment behavior
  * [_.pull](https://lodash.com/docs#pull), [_.pullAt](https://lodash.com/docs#pullAt), & [_.remove](https://lodash.com/docs#remove) for mutating arrays
@@ -93,6 +95,7 @@ lodash is also available in a variety of other builds & module formats.
  * [_.support](https://lodash.com/docs#support) for flagging environment features
  * [_.template](https://lodash.com/docs#template) supports [*“imports”*](https://lodash.com/docs#templateSettings-imports) options & [ES template delimiters](http://people.mozilla.org/~jorendorff/es6-draft.html#sec-template-literal-lexical-components)
  * [_.transform](https://lodash.com/docs#transform) as a powerful alternative to [_.reduce](https://lodash.com/docs#reduce) for transforming objects
+ * [_.unzipWith](https://lodash.com/docs#unzipWith) & [_.zipWith](https://lodash.com/docs#zipWith) to specify how grouped values should be combined
  * [_.xor](https://lodash.com/docs#xor) to complement [_.difference](https://lodash.com/docs#difference), [_.intersection](https://lodash.com/docs#intersection), & [_.union](https://lodash.com/docs#union)
  * [_.valuesIn](https://lodash.com/docs#valuesIn) for getting values of all enumerable properties
  * [_.bind](https://lodash.com/docs#bind), [_.curry](https://lodash.com/docs#curry), [_.partial](https://lodash.com/docs#partial), &
@@ -100,17 +103,17 @@ lodash is also available in a variety of other builds & module formats.
  * [_.capitalize](https://lodash.com/docs#capitalize), [_.trim](https://lodash.com/docs#trim), &
    [more](https://lodash.com/docs "_.camelCase, _.deburr, _.endsWith, _.escapeRegExp, _.kebabCase, _.pad, _.padLeft, _.padRight, _.repeat, _.snakeCase, _.startCase, _.startsWith, _.trimLeft, _.trimRight, _.trunc, _.words") string methods
  * [_.clone](https://lodash.com/docs#clone), [_.isEqual](https://lodash.com/docs#isEqual), &
-   [more](https://lodash.com/docs "_.assign, _.cloneDeep, _.merge") accept callbacks
+   [more](https://lodash.com/docs "_.assign, _.cloneDeep, _.merge") accept customizer callbacks
  * [_.dropWhile](https://lodash.com/docs#dropWhile), [_.takeWhile](https://lodash.com/docs#takeWhile), &
-   [more](https://lodash.com/docs "_.drop, _.dropRightWhile, _.take, _.takeRightWhile") to complement [_.first](https://lodash.com/docs#first), [_.initial](https://lodash.com/docs#initial), [_.last](https://lodash.com/docs#last), & [_.rest](https://lodash.com/docs#rest)
+   [more](https://lodash.com/docs "_.drop, _.dropRight, _.dropRightWhile, _.take, _.takeRight, _.takeRightWhile") to complement [_.first](https://lodash.com/docs#first), [_.initial](https://lodash.com/docs#initial), [_.last](https://lodash.com/docs#last), & [_.rest](https://lodash.com/docs#rest)
  * [_.findLast](https://lodash.com/docs#findLast), [_.findLastKey](https://lodash.com/docs#findLastKey), &
-   [more](https://lodash.com/docs "_.flowRight, _.forEachRight, _.forInRight, _.forOwnRight, _.partialRight") right-associative methods
+   [more](https://lodash.com/docs "_.curryRight, _.dropRight, _.dropRightWhile, _.flowRight, _.forEachRight, _.forInRight, _.forOwnRight, _.padRight, partialRight, _.takeRight, _.trimRight, _.takeRightWhile") right-associative methods
  * [_.includes](https://lodash.com/docs#includes), [_.toArray](https://lodash.com/docs#toArray), &
-   [more](https://lodash.com/docs "_.at, _.countBy, _.every, _.filter, _.find, _.findLast, _.forEach, _.forEachRight, _.groupBy, _.indexBy, _.invoke, _.map, _.max, _.min, _.partition, _.pluck, _.reduce, _.reduceRight, _.reject, _.shuffle, _.size, _.some, _.sortBy") accept strings
+   [more](https://lodash.com/docs "_.at, _.countBy, _.every, _.filter, _.find, _.findLast, _.findWhere, _.forEach, _.forEachRight, _.groupBy, _.indexBy, _.invoke, _.map, _.max, _.min, _.partition, _.pluck, _.reduce, _.reduceRight, _.reject, _.shuffle, _.size, _.some, _.sortBy, _.sortByAll, _.sortByOrder, _.sum, _.where") accept strings
  * [_#commit](https://lodash.com/docs#prototype-commit) & [_#plant](https://lodash.com/docs#prototype-plant) for working with chain sequences
  * [_#thru](https://lodash.com/docs#thru) to pass values thru a chain sequence
 
 ## Support
 
-Tested in Chrome 40-41, Firefox 35-36, IE 6-11, Opera 27-28, Safari 5-8, io.js 1.6.2, Node.js 0.8.28, 0.10.36, & 0.12.0, PhantomJS 1.9.8, RingoJS 0.11, & Rhino 1.7RC5.
+Tested in Chrome 41-42, Firefox 36-37, IE 6-11, MS Edge, Opera 27-28, Safari 5-8, io.js 1.8.1, Node.js 0.8.28, 0.10.38, & 0.12.2, PhantomJS 1.9.8, RingoJS 0.11, & Rhino 1.7RC5.
 Automated [browser](https://saucelabs.com/u/lodash) & [CI](https://travis-ci.org/lodash/lodash/) test runs are available. Special thanks to [Sauce Labs](https://saucelabs.com/) for providing automated browser testing.

array.js

@@ -35,8 +35,10 @@ module.exports = {
   'uniq': require('./array/uniq'),
   'unique': require('./array/unique'),
   'unzip': require('./array/unzip'),
+  'unzipWith': require('./array/unzipWith'),
   'without': require('./array/without'),
   'xor': require('./array/xor'),
   'zip': require('./array/zip'),
-  'zipObject': require('./array/zipObject')
+  'zipObject': require('./array/zipObject'),
+  'zipWith': require('./array/zipWith')
 };

array/difference.js

@@ -1,16 +1,12 @@
 var baseDifference = require('../internal/baseDifference'),
     baseFlatten = require('../internal/baseFlatten'),
-    isArguments = require('../lang/isArguments'),
+    isArrayLike = require('../internal/isArrayLike'),
-    isArray = require('../lang/isArray'),
     restParam = require('../function/restParam');
 
 /**
  * Creates an array excluding all values of the provided arrays using
- * `SameValueZero` for equality comparisons.
+ * [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
- *
+ * for equality comparisons.
- * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
- * comparisons are like strict equality comparisons, e.g. `===`, except that
- * `NaN` matches `NaN`.
  *
  * @static
  * @memberOf _
@@ -24,7 +20,7 @@ var baseDifference = require('../internal/baseDifference'),
  * // => [1, 3]
  */
 var difference = restParam(function(array, values) {
-  return (isArray(array) || isArguments(array))
+  return isArrayLike(array)
     ? baseDifference(array, baseFlatten(values, false, true))
     : [];
 });

array/indexOf.js

@@ -6,13 +6,10 @@ var nativeMax = Math.max;
 
 /**
  * Gets the index at which the first occurrence of `value` is found in `array`
- * using `SameValueZero` for equality comparisons. If `fromIndex` is negative,
+ * using [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
- * it is used as the offset from the end of `array`. If `array` is sorted
+ * for equality comparisons. If `fromIndex` is negative, it is used as the offset
- * providing `true` for `fromIndex` performs a faster binary search.
+ * from the end of `array`. If `array` is sorted providing `true` for `fromIndex`
- *
+ * performs a faster binary search.
- * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
- * comparisons are like strict equality comparisons, e.g. `===`, except that
- * `NaN` matches `NaN`.
  *
  * @static
  * @memberOf _

array/intersection.js

@@ -1,17 +1,13 @@
 var baseIndexOf = require('../internal/baseIndexOf'),
     cacheIndexOf = require('../internal/cacheIndexOf'),
     createCache = require('../internal/createCache'),
-    isArguments = require('../lang/isArguments'),
+    isArrayLike = require('../internal/isArrayLike');
-    isArray = require('../lang/isArray');
 
 /**
- * Creates an array of unique values in all provided arrays using `SameValueZero`
+ * Creates an array of unique values in all provided arrays using
+ * [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
  * for equality comparisons.
  *
- * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
- * comparisons are like strict equality comparisons, e.g. `===`, except that
- * `NaN` matches `NaN`.
- *
  * @static
  * @memberOf _
  * @category Array
@@ -27,20 +23,23 @@ function intersection() {
       argsLength = arguments.length,
       caches = [],
       indexOf = baseIndexOf,
-      isCommon = true;
+      isCommon = true,
+      result = [];
 
   while (++argsIndex < argsLength) {
     var value = arguments[argsIndex];
-    if (isArray(value) || isArguments(value)) {
+    if (isArrayLike(value)) {
       args.push(value);
       caches.push((isCommon && value.length >= 120) ? createCache(argsIndex && value) : null);
     }
   }
   argsLength = args.length;
+  if (argsLength < 2) {
+    return result;
+  }
   var array = args[0],
       index = -1,
       length = array ? array.length : 0,
-      result = [],
       seen = caches[0];
 
   outer:

array/pull.js

@@ -7,14 +7,11 @@ var arrayProto = Array.prototype;
 var splice = arrayProto.splice;
 
 /**
- * Removes all provided values from `array` using `SameValueZero` for equality
+ * Removes all provided values from `array` using
- * comparisons.
+ * [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
+ * for equality comparisons.
  *
- * **Notes:**
+ * **Note:** Unlike `_.without`, this method mutates `array`.
- *  - Unlike `_.without`, this method mutates `array`
- *  - [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
- *    comparisons are like strict equality comparisons, e.g. `===`, except
- *    that `NaN` matches `NaN`
  *
  * @static
  * @memberOf _

array/pullAt.js

@@ -1,15 +1,9 @@
 var baseAt = require('../internal/baseAt'),
     baseCompareAscending = require('../internal/baseCompareAscending'),
     baseFlatten = require('../internal/baseFlatten'),
-    isIndex = require('../internal/isIndex'),
+    basePullAt = require('../internal/basePullAt'),
     restParam = require('../function/restParam');
 
-/** Used for native method references. */
-var arrayProto = Array.prototype;
-
-/** Native method references. */
-var splice = arrayProto.splice;
-
 /**
  * Removes elements from `array` corresponding to the given indexes and returns
  * an array of the removed elements. Indexes may be specified as an array of
@@ -36,20 +30,10 @@ var splice = arrayProto.splice;
  * // => [10, 20]
  */
 var pullAt = restParam(function(array, indexes) {
-  array || (array = []);
   indexes = baseFlatten(indexes);
 
-  var length = indexes.length,
+  var result = baseAt(array, indexes);
-      result = baseAt(array, indexes);
+  basePullAt(array, indexes.sort(baseCompareAscending));
-
-  indexes.sort(baseCompareAscending);
-  while (length--) {
-    var index = parseFloat(indexes[length]);
-    if (index != previous && isIndex(index)) {
-      var previous = index;
-      splice.call(array, index, 1);
-    }
-  }
   return result;
 });
 

array/remove.js

@@ -1,10 +1,5 @@
-var baseCallback = require('../internal/baseCallback');
+var baseCallback = require('../internal/baseCallback'),
-
+    basePullAt = require('../internal/basePullAt');
-/** Used for native method references. */
-var arrayProto = Array.prototype;
-
-/** Native method references. */
-var splice = arrayProto.splice;
 
 /**
  * Removes all elements from `array` that `predicate` returns truthy for
@@ -46,19 +41,23 @@ var splice = arrayProto.splice;
  * // => [2, 4]
  */
 function remove(array, predicate, thisArg) {
+  var result = [];
+  if (!(array && array.length)) {
+    return result;
+  }
   var index = -1,
-      length = array ? array.length : 0,
+      indexes = [],
-      result = [];
+      length = array.length;
 
   predicate = baseCallback(predicate, thisArg, 3);
   while (++index < length) {
     var value = array[index];
     if (predicate(value, index, array)) {
       result.push(value);
-      splice.call(array, index--, 1);
+      indexes.push(index);
-      length--;
     }
   }
+  basePullAt(array, indexes);
   return result;
 }
 

array/slice.js

@@ -4,7 +4,7 @@ var baseSlice = require('../internal/baseSlice'),
 /**
  * Creates a slice of `array` from `start` up to, but not including, `end`.
  *
- * **Note:** This function is used instead of `Array#slice` to support node
+ * **Note:** This method is used instead of `Array#slice` to support node
  * lists in IE < 9 and to ensure dense arrays are returned.
  *
  * @static

array/union.js

@@ -4,11 +4,8 @@ var baseFlatten = require('../internal/baseFlatten'),
 
 /**
  * Creates an array of unique values, in order, of the provided arrays using
- * `SameValueZero` for equality comparisons.
+ * [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
- *
+ * for equality comparisons.
- * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
- * comparisons are like strict equality comparisons, e.g. `===`, except that
- * `NaN` matches `NaN`.
  *
  * @static
  * @memberOf _

array/uniq.js

@@ -4,12 +4,14 @@ var baseCallback = require('../internal/baseCallback'),
     sortedUniq = require('../internal/sortedUniq');
 
 /**
- * Creates a duplicate-value-free version of an array using `SameValueZero`
+ * Creates a duplicate-free version of an array, using
- * for equality comparisons. Providing `true` for `isSorted` performs a faster
+ * [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
- * search algorithm for sorted arrays. If an iteratee function is provided it
+ * for equality comparisons, in which only the first occurence of each element
- * is invoked for each value in the array to generate the criterion by which
+ * is kept. Providing `true` for `isSorted` performs a faster search algorithm
- * uniqueness is computed. The `iteratee` is bound to `thisArg` and invoked
+ * for sorted arrays. If an iteratee function is provided it is invoked for
- * with three arguments: (value, index, array).
+ * each element in the array to generate the criterion by which uniqueness
+ * is computed. The `iteratee` is bound to `thisArg` and invoked with three
+ * arguments: (value, index, array).
  *
  * If a property name is provided for `iteratee` the created `_.property`
  * style callback returns the property value of the given element.
@@ -22,10 +24,6 @@ var baseCallback = require('../internal/baseCallback'),
  * callback returns `true` for elements that have the properties of the given
  * object, else `false`.
  *
- * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
- * comparisons are like strict equality comparisons, e.g. `===`, except that
- * `NaN` matches `NaN`.
- *
  * @static
  * @memberOf _
  * @alias unique
@@ -37,8 +35,8 @@ var baseCallback = require('../internal/baseCallback'),
  * @returns {Array} Returns the new duplicate-value-free array.
  * @example
  *
- * _.uniq([1, 2, 1]);
+ * _.uniq([2, 1, 2]);
- * // => [1, 2]
+ * // => [2, 1]
  *
  * // using `isSorted`
  * _.uniq([1, 1, 2], true);

array/unzip.js

@@ -1,13 +1,14 @@
-var arrayMap = require('../internal/arrayMap'),
+var arrayFilter = require('../internal/arrayFilter'),
-    arrayMax = require('../internal/arrayMax'),
+    arrayMap = require('../internal/arrayMap'),
-    baseProperty = require('../internal/baseProperty');
+    baseProperty = require('../internal/baseProperty'),
+    isArrayLike = require('../internal/isArrayLike');
 
-/** Used to the length of n-tuples for `_.unzip`. */
+/* Native method references for those with the same name as other `lodash` methods. */
-var getLength = baseProperty('length');
+var nativeMax = Math.max;
 
 /**
  * This method is like `_.zip` except that it accepts an array of grouped
- * elements and creates an array regrouping the elements to their pre-`_.zip`
+ * elements and creates an array regrouping the elements to their pre-zip
  * configuration.
  *
  * @static
@@ -24,10 +25,19 @@ var getLength = baseProperty('length');
  * // => [['fred', 'barney'], [30, 40], [true, false]]
  */
 function unzip(array) {
+  if (!(array && array.length)) {
+    return [];
+  }
   var index = -1,
-      length = (array && array.length && arrayMax(arrayMap(array, getLength))) >>> 0,
+      length = 0;
-      result = Array(length);
 
+  array = arrayFilter(array, function(group) {
+    if (isArrayLike(group)) {
+      length = nativeMax(group.length, length);
+      return true;
+    }
+  });
+  var result = Array(length);
   while (++index < length) {
     result[index] = arrayMap(array, baseProperty(index));
   }

array/unzipWith.js

@@ -0,0 +1,41 @@
+var arrayMap = require('../internal/arrayMap'),
+    arrayReduce = require('../internal/arrayReduce'),
+    bindCallback = require('../internal/bindCallback'),
+    unzip = require('./unzip');
+
+/**
+ * This method is like `_.unzip` except that it accepts an iteratee to specify
+ * how regrouped values should be combined. The `iteratee` is bound to `thisArg`
+ * and invoked with four arguments: (accumulator, value, index, group).
+ *
+ * @static
+ * @memberOf _
+ * @category Array
+ * @param {Array} array The array of grouped elements to process.
+ * @param {Function} [iteratee] The function to combine regrouped values.
+ * @param {*} [thisArg] The `this` binding of `iteratee`.
+ * @returns {Array} Returns the new array of regrouped elements.
+ * @example
+ *
+ * var zipped = _.zip([1, 2], [10, 20], [100, 200]);
+ * // => [[1, 10, 100], [2, 20, 200]]
+ *
+ * _.unzipWith(zipped, _.add);
+ * // => [3, 30, 300]
+ */
+function unzipWith(array, iteratee, thisArg) {
+  var length = array ? array.length : 0;
+  if (!length) {
+    return [];
+  }
+  var result = unzip(array);
+  if (iteratee == null) {
+    return result;
+  }
+  iteratee = bindCallback(iteratee, thisArg, 4);
+  return arrayMap(result, function(group) {
+    return arrayReduce(group, iteratee, undefined, true);
+  });
+}
+
+module.exports = unzipWith;

array/without.js

@@ -1,15 +1,11 @@
 var baseDifference = require('../internal/baseDifference'),
-    isArguments = require('../lang/isArguments'),
+    isArrayLike = require('../internal/isArrayLike'),
-    isArray = require('../lang/isArray'),
     restParam = require('../function/restParam');
 
 /**
- * Creates an array excluding all provided values using `SameValueZero` for
+ * Creates an array excluding all provided values using
- * equality comparisons.
+ * [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
- *
+ * for equality comparisons.
- * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
- * comparisons are like strict equality comparisons, e.g. `===`, except that
- * `NaN` matches `NaN`.
  *
  * @static
  * @memberOf _
@@ -23,7 +19,7 @@ var baseDifference = require('../internal/baseDifference'),
  * // => [3]
  */
 var without = restParam(function(array, values) {
-  return (isArray(array) || isArguments(array))
+  return isArrayLike(array)
     ? baseDifference(array, values)
     : [];
 });

array/xor.js

@@ -1,7 +1,6 @@
 var baseDifference = require('../internal/baseDifference'),
     baseUniq = require('../internal/baseUniq'),
-    isArguments = require('../lang/isArguments'),
+    isArrayLike = require('../internal/isArrayLike');
-    isArray = require('../lang/isArray');
 
 /**
  * Creates an array that is the [symmetric difference](https://en.wikipedia.org/wiki/Symmetric_difference)
@@ -23,7 +22,7 @@ function xor() {
 
   while (++index < length) {
     var array = arguments[index];
-    if (isArray(array) || isArguments(array)) {
+    if (isArrayLike(array)) {
       var result = result
         ? baseDifference(result, array).concat(baseDifference(array, result))
         : array;

array/zipWith.js

@@ -0,0 +1,36 @@
+var restParam = require('../function/restParam'),
+    unzipWith = require('./unzipWith');
+
+/**
+ * This method is like `_.zip` except that it accepts an iteratee to specify
+ * how grouped values should be combined. The `iteratee` is bound to `thisArg`
+ * and invoked with four arguments: (accumulator, value, index, group).
+ *
+ * @static
+ * @memberOf _
+ * @category Array
+ * @param {...Array} [arrays] The arrays to process.
+ * @param {Function} [iteratee] The function to combine grouped values.
+ * @param {*} [thisArg] The `this` binding of `iteratee`.
+ * @returns {Array} Returns the new array of grouped elements.
+ * @example
+ *
+ * _.zipWith([1, 2], [10, 20], [100, 200], _.add);
+ * // => [111, 222]
+ */
+var zipWith = restParam(function(arrays) {
+  var length = arrays.length,
+      iteratee = arrays[length - 2],
+      thisArg = arrays[length - 1];
+
+  if (length > 2 && typeof iteratee == 'function') {
+    length -= 2;
+  } else {
+    iteratee = (length > 1 && typeof thisArg == 'function') ? (--length, thisArg) : undefined;
+    thisArg = undefined;
+  }
+  arrays.length = length;
+  return unzipWith(arrays, iteratee, thisArg);
+});
+
+module.exports = zipWith;

chain/lodash.js

@@ -50,8 +50,8 @@ var hasOwnProperty = objectProto.hasOwnProperty;
  * `filter`, `flatten`, `flattenDeep`, `flow`, `flowRight`, `forEach`,
  * `forEachRight`, `forIn`, `forInRight`, `forOwn`, `forOwnRight`, `functions`,
  * `groupBy`, `indexBy`, `initial`, `intersection`, `invert`, `invoke`, `keys`,
- * `keysIn`, `map`, `mapValues`, `matches`, `matchesProperty`, `memoize`, `merge`,
+ * `keysIn`, `map`, `mapValues`, `matches`, `matchesProperty`, `memoize`,
- * `mixin`, `negate`, `noop`, `omit`, `once`, `pairs`, `partial`, `partialRight`,
+ * `merge`, `mixin`, `negate`, `omit`, `once`, `pairs`, `partial`, `partialRight`,
  * `partition`, `pick`, `plant`, `pluck`, `property`, `propertyOf`, `pull`,
  * `pullAt`, `push`, `range`, `rearg`, `reject`, `remove`, `rest`, `reverse`,
  * `shuffle`, `slice`, `sort`, `sortBy`, `sortByAll`, `sortByOrder`, `splice`,
@@ -65,15 +65,15 @@ var hasOwnProperty = objectProto.hasOwnProperty;
  * `endsWith`, `escape`, `escapeRegExp`, `every`, `find`, `findIndex`, `findKey`,
  * `findLast`, `findLastIndex`, `findLastKey`, `findWhere`, `first`, `has`,
  * `identity`, `includes`, `indexOf`, `inRange`, `isArguments`, `isArray`,
- * `isBoolean`, `isDate`, `isElement`, `isEmpty`, `isEqual`, `isError`,
+ * `isBoolean`, `isDate`, `isElement`, `isEmpty`, `isEqual`, `isError`, `isFinite`
- * `isFinite`,`isFunction`, `isMatch`, `isNative`, `isNaN`, `isNull`, `isNumber`,
+ * `isFunction`, `isMatch`, `isNative`, `isNaN`, `isNull`, `isNumber`, `isObject`,
- * `isObject`, `isPlainObject`, `isRegExp`, `isString`, `isUndefined`,
+ * `isPlainObject`, `isRegExp`, `isString`, `isUndefined`, `isTypedArray`,
- * `isTypedArray`, `join`, `kebabCase`, `last`, `lastIndexOf`, `max`, `min`,
+ * `join`, `kebabCase`, `last`, `lastIndexOf`, `max`, `min`, `noConflict`,
- * `noConflict`, `now`, `pad`, `padLeft`, `padRight`, `parseInt`, `pop`,
+ * `noop`, `now`, `pad`, `padLeft`, `padRight`, `parseInt`, `pop`, `random`,
- * `random`, `reduce`, `reduceRight`, `repeat`, `result`, `runInContext`,
+ * `reduce`, `reduceRight`, `repeat`, `result`, `runInContext`, `shift`, `size`,
- * `shift`, `size`, `snakeCase`, `some`, `sortedIndex`, `sortedLastIndex`,
+ * `snakeCase`, `some`, `sortedIndex`, `sortedLastIndex`, `startCase`, `startsWith`,
- * `startCase`, `startsWith`, `sum`, `template`, `trim`, `trimLeft`,
+ * `sum`, `template`, `trim`, `trimLeft`, `trimRight`, `trunc`, `unescape`,
- * `trimRight`, `trunc`, `unescape`, `uniqueId`, `value`, and `words`
+ * `uniqueId`, `value`, and `words`
  *
  * The wrapper method `sample` will return a wrapped value when `n` is provided,
  * otherwise an unwrapped value is returned.
@@ -88,8 +88,8 @@ var hasOwnProperty = objectProto.hasOwnProperty;
  * var wrapped = _([1, 2, 3]);
  *
  * // returns an unwrapped value
- * wrapped.reduce(function(sum, n) {
+ * wrapped.reduce(function(total, n) {
- *   return sum + n;
+ *   return total + n;
  * });
  * // => 6
  *

collection/at.js

@@ -1,8 +1,6 @@
 var baseAt = require('../internal/baseAt'),
     baseFlatten = require('../internal/baseFlatten'),
-    isLength = require('../internal/isLength'),
+    restParam = require('../function/restParam');
-    restParam = require('../function/restParam'),
-    toIterable = require('../internal/toIterable');
 
 /**
  * Creates an array of elements corresponding to the given keys, or indexes,
@@ -25,10 +23,6 @@ var baseAt = require('../internal/baseAt'),
  * // => ['barney', 'pebbles']
  */
 var at = restParam(function(collection, props) {
-  var length = collection ? collection.length : 0;
-  if (isLength(length)) {
-    collection = toIterable(collection);
-  }
   return baseAt(collection, baseFlatten(props));
 });
 

collection/every.js

@@ -57,7 +57,7 @@ function every(collection, predicate, thisArg) {
   if (thisArg && isIterateeCall(collection, predicate, thisArg)) {
     predicate = null;
   }
-  if (typeof predicate != 'function' || typeof thisArg != 'undefined') {
+  if (typeof predicate != 'function' || thisArg !== undefined) {
     predicate = baseCallback(predicate, thisArg, 3);
   }
   return func(collection, predicate);

collection/forEach.js

@@ -5,10 +5,10 @@ var arrayEach = require('../internal/arrayEach'),
 /**
  * Iterates over elements of `collection` invoking `iteratee` for each element.
  * The `iteratee` is bound to `thisArg` and invoked with three arguments:
- * (value, index|key, collection). Iterator functions may exit iteration early
+ * (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
+ * **Note:** As with other "Collections" methods, objects with a "length" property
  * are iterated like arrays. To avoid this behavior `_.forIn` or `_.forOwn`
  * may be used for object iteration.
  *

collection/includes.js

@@ -1,4 +1,5 @@
 var baseIndexOf = require('../internal/baseIndexOf'),
+    getLength = require('../internal/getLength'),
     isArray = require('../lang/isArray'),
     isIterateeCall = require('../internal/isIterateeCall'),
     isLength = require('../internal/isLength'),
@@ -9,13 +10,10 @@ var baseIndexOf = require('../internal/baseIndexOf'),
 var nativeMax = Math.max;
 
 /**
- * Checks if `value` is in `collection` using `SameValueZero` for equality
+ * Checks if `value` is in `collection` using
- * comparisons. If `fromIndex` is negative, it is used as the offset from
+ * [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
- * the end of `collection`.
+ * for equality comparisons. If `fromIndex` is negative, it is used as the offset
- *
+ * from the end of `collection`.
- * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
- * comparisons are like strict equality comparisons, e.g. `===`, except that
- * `NaN` matches `NaN`.
  *
  * @static
  * @memberOf _
@@ -41,7 +39,7 @@ var nativeMax = Math.max;
  * // => true
  */
 function includes(collection, target, fromIndex, guard) {
-  var length = collection ? collection.length : 0;
+  var length = collection ? getLength(collection) : 0;
   if (!isLength(length)) {
     collection = values(collection);
     length = collection.length;

collection/invoke.js

@@ -1,18 +1,20 @@
 var baseEach = require('../internal/baseEach'),
-    isLength = require('../internal/isLength'),
+    invokePath = require('../internal/invokePath'),
+    isArrayLike = require('../internal/isArrayLike'),
+    isKey = require('../internal/isKey'),
     restParam = require('../function/restParam');
 
 /**
- * Invokes the method named by `methodName` on each element in `collection`,
+ * Invokes the method at `path` on each element in `collection`, returning
- * returning an array of the results of each invoked method. Any additional
+ * an array of the results of each invoked method. Any additional arguments
- * arguments are provided to each invoked method. If `methodName` is a function
+ * are provided to each invoked method. If `methodName` is a function it is
- * it is invoked for, and `this` bound to, each element in `collection`.
+ * invoked for, and `this` bound to, each element in `collection`.
  *
  * @static
  * @memberOf _
  * @category Collection
  * @param {Array|Object|string} collection The collection to iterate over.
- * @param {Function|string} methodName The name of the method to invoke or
+ * @param {Array|Function|string} path The path of the method to invoke or
  *  the function invoked per iteration.
  * @param {...*} [args] The arguments to invoke the method with.
  * @returns {Array} Returns the array of results.
@@ -24,15 +26,15 @@ var baseEach = require('../internal/baseEach'),
  * _.invoke([123, 456], String.prototype.split, '');
  * // => [['1', '2', '3'], ['4', '5', '6']]
  */
-var invoke = restParam(function(collection, methodName, args) {
+var invoke = restParam(function(collection, path, args) {
   var index = -1,
-      isFunc = typeof methodName == 'function',
+      isFunc = typeof path == 'function',
-      length = collection ? collection.length : 0,
+      isProp = isKey(path),
-      result = isLength(length) ? Array(length) : [];
+      result = isArrayLike(collection) ? Array(collection.length) : [];
 
   baseEach(collection, function(value) {
-    var func = isFunc ? methodName : (value != null && value[methodName]);
+    var func = isFunc ? path : (isProp && value != null && value[path]);
-    result[++index] = func ? func.apply(value, args) : undefined;
+    result[++index] = func ? func.apply(value, args) : invokePath(value, path, args);
   });
   return result;
 });

collection/map.js

@@ -23,10 +23,11 @@ var arrayMap = require('../internal/arrayMap'),
  * `_.every`, `_.filter`, `_.map`, `_.mapValues`, `_.reject`, and `_.some`.
  *
  * The guarded methods are:
- * `ary`, `callback`, `chunk`, `clone`, `create`, `curry`, `curryRight`, `drop`,
+ * `ary`, `callback`, `chunk`, `clone`, `create`, `curry`, `curryRight`,
- * `dropRight`, `every`, `fill`, `flatten`, `invert`, `max`, `min`, `parseInt`,
+ * `drop`, `dropRight`, `every`, `fill`, `flatten`, `invert`, `max`, `min`,
- * `slice`, `sortBy`, `take`, `takeRight`, `template`, `trim`, `trimLeft`,
+ * `parseInt`, `slice`, `sortBy`, `take`, `takeRight`, `template`, `trim`,
- * `trimRight`, `trunc`, `random`, `range`, `sample`, `some`, `uniq`, and `words`
+ * `trimLeft`, `trimRight`, `trunc`, `random`, `range`, `sample`, `some`,
+ * `sum`, `uniq`, and `words`
  *
  * @static
  * @memberOf _
@@ -35,7 +36,6 @@ var arrayMap = require('../internal/arrayMap'),
  * @param {Array|Object|string} collection The collection to iterate over.
  * @param {Function|Object|string} [iteratee=_.identity] The function invoked
  *  per iteration.
- *  create a `_.property` or `_.matches` style callback respectively.
  * @param {*} [thisArg] The `this` binding of `iteratee`.
  * @returns {Array} Returns the new mapped array.
  * @example

collection/pluck.js

@@ -1,14 +1,14 @@
-var baseProperty = require('../internal/baseProperty'),
+var map = require('./map'),
-    map = require('./map');
+    property = require('../utility/property');
 
 /**
- * Gets the value of `key` from all elements in `collection`.
+ * Gets the property value of `path` from all elements in `collection`.
  *
  * @static
  * @memberOf _
  * @category Collection
  * @param {Array|Object|string} collection The collection to iterate over.
- * @param {string} key The key of the property to pluck.
+ * @param {Array|string} path The path of the property to pluck.
  * @returns {Array} Returns the property values.
  * @example
  *
@@ -24,8 +24,8 @@ var baseProperty = require('../internal/baseProperty'),
  * _.pluck(userIndex, 'age');
  * // => [36, 40] (iteration order is not guaranteed)
  */
-function pluck(collection, key) {
+function pluck(collection, path) {
-  return map(collection, baseProperty(key));
+  return map(collection, property(path));
 }
 
 module.exports = pluck;

collection/reduce.js

@@ -27,8 +27,8 @@ var arrayReduce = require('../internal/arrayReduce'),
  * @returns {*} Returns the accumulated value.
  * @example
  *
- * _.reduce([1, 2], function(sum, n) {
+ * _.reduce([1, 2], function(total, n) {
- *   return sum + n;
+ *   return total + n;
  * });
  * // => 3
  *

collection/reduceRight.js

@@ -24,6 +24,6 @@ var arrayReduceRight = require('../internal/arrayReduceRight'),
  * }, []);
  * // => [4, 5, 2, 3, 0, 1]
  */
-var reduceRight =  createReduce(arrayReduceRight, baseEachRight);
+var reduceRight = createReduce(arrayReduceRight, baseEachRight);
 
 module.exports = reduceRight;

collection/reject.js

@@ -7,17 +7,6 @@ var arrayFilter = require('../internal/arrayFilter'),
  * The opposite of `_.filter`; this method returns the elements of `collection`
  * that `predicate` does **not** return truthy for.
  *
- * If a property name is provided for `predicate` the created `_.property`
- * style callback returns the property value of the given element.
- *
- * If a value is also provided for `thisArg` the created `_.matchesProperty`
- * style callback returns `true` for elements that have a matching property
- * value, else `false`.
- *
- * If an object is provided for `predicate` the created `_.matches` style
- * callback returns `true` for elements that have the properties of the given
- * object, else `false`.
- *
  * @static
  * @memberOf _
  * @category Collection

collection/size.js

@@ -1,4 +1,5 @@
-var isLength = require('../internal/isLength'),
+var getLength = require('../internal/getLength'),
+    isLength = require('../internal/isLength'),
     keys = require('../object/keys');
 
 /**
@@ -22,7 +23,7 @@ var isLength = require('../internal/isLength'),
  * // => 7
  */
 function size(collection) {
-  var length = collection ? collection.length : 0;
+  var length = collection ? getLength(collection) : 0;
   return isLength(length) ? length : keys(collection).length;
 }
 

collection/some.js

@@ -58,7 +58,7 @@ function some(collection, predicate, thisArg) {
   if (thisArg && isIterateeCall(collection, predicate, thisArg)) {
     predicate = null;
   }
-  if (typeof predicate != 'function' || typeof thisArg != 'undefined') {
+  if (typeof predicate != 'function' || thisArg !== undefined) {
     predicate = baseCallback(predicate, thisArg, 3);
   }
   return func(collection, predicate);

collection/sortBy.js

@@ -1,9 +1,8 @@
 var baseCallback = require('../internal/baseCallback'),
-    baseEach = require('../internal/baseEach'),
+    baseMap = require('../internal/baseMap'),
     baseSortBy = require('../internal/baseSortBy'),
     compareAscending = require('../internal/compareAscending'),
-    isIterateeCall = require('../internal/isIterateeCall'),
+    isIterateeCall = require('../internal/isIterateeCall');
-    isLength = require('../internal/isLength');
 
 /**
  * Creates an array of elements, sorted in ascending order by the results of
@@ -27,9 +26,8 @@ var baseCallback = require('../internal/baseCallback'),
  * @memberOf _
  * @category Collection
  * @param {Array|Object|string} collection The collection to iterate over.
- * @param {Array|Function|Object|string} [iteratee=_.identity] The function
+ * @param {Function|Object|string} [iteratee=_.identity] The function invoked
- *  invoked per iteration. If a property name or an object is provided it is
+ *  per iteration.
- *  used to create a `_.property` or `_.matches` style callback respectively.
  * @param {*} [thisArg] The `this` binding of `iteratee`.
  * @returns {Array} Returns the new sorted array.
  * @example
@@ -58,16 +56,14 @@ function sortBy(collection, iteratee, thisArg) {
   if (collection == null) {
     return [];
   }
-  var index = -1,
-      length = collection.length,
-      result = isLength(length) ? Array(length) : [];
-
   if (thisArg && isIterateeCall(collection, iteratee, thisArg)) {
     iteratee = null;
   }
+  var index = -1;
   iteratee = baseCallback(iteratee, thisArg, 3);
-  baseEach(collection, function(value, key, collection) {
+
-    result[++index] = { 'criteria': iteratee(value, key, collection), 'index': index, 'value': value };
+  var result = baseMap(collection, function(value, key, collection) {
+    return { 'criteria': iteratee(value, key, collection), 'index': ++index, 'value': value };
   });
   return baseSortBy(result, compareAscending);
 }

collection/sortByAll.js

@@ -1,48 +1,52 @@
 var baseFlatten = require('../internal/baseFlatten'),
     baseSortByOrder = require('../internal/baseSortByOrder'),
-    isIterateeCall = require('../internal/isIterateeCall');
+    isIterateeCall = require('../internal/isIterateeCall'),
+    restParam = require('../function/restParam');
 
 /**
- * This method is like `_.sortBy` except that it sorts by property names
+ * This method is like `_.sortBy` except that it can sort by multiple iteratees
- * instead of an iteratee function.
+ * or property names.
+ *
+ * If a property name is provided for an iteratee the created `_.property`
+ * style callback returns the property value of the given element.
+ *
+ * If an object is provided for an iteratee the created `_.matches` style
+ * callback returns `true` for elements that have the properties of the given
+ * object, else `false`.
  *
  * @static
  * @memberOf _
  * @category Collection
  * @param {Array|Object|string} collection The collection to iterate over.
- * @param {...(string|string[])} props The property names to sort by,
+ * @param {...(Function|Function[]|Object|Object[]|string|string[])} iteratees
- *  specified as individual property names or arrays of property names.
+ *  The iteratees to sort by, specified as individual values or arrays of values.
  * @returns {Array} Returns the new sorted array.
  * @example
  *
  * var users = [
+ *   { 'user': 'fred',   'age': 48 },
  *   { 'user': 'barney', 'age': 36 },
- *   { 'user': 'fred',   'age': 40 },
+ *   { 'user': 'fred',   'age': 42 },
- *   { 'user': 'barney', 'age': 26 },
+ *   { 'user': 'barney', 'age': 34 }
- *   { 'user': 'fred',   'age': 30 }
  * ];
  *
  * _.map(_.sortByAll(users, ['user', 'age']), _.values);
- * // => [['barney', 26], ['barney', 36], ['fred', 30], ['fred', 40]]
+ * // => [['barney', 34], ['barney', 36], ['fred', 42], ['fred', 48]]
+ *
+ * _.map(_.sortByAll(users, 'user', function(chr) {
+ *   return Math.floor(chr.age / 10);
+ * }), _.values);
+ * // => [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 42]]
  */
-function sortByAll() {
+var sortByAll = restParam(function(collection, iteratees) {
-  var args = arguments,
-      collection = args[0],
-      guard = args[3],
-      index = 0,
-      length = args.length - 1;
-
   if (collection == null) {
     return [];
   }
-  var props = Array(length);
+  var guard = iteratees[2];
-  while (index < length) {
+  if (guard && isIterateeCall(iteratees[0], iteratees[1], guard)) {
-    props[index] = args[++index];
+    iteratees.length = 1;
   }
-  if (guard && isIterateeCall(args[1], args[2], guard)) {
+  return baseSortByOrder(collection, baseFlatten(iteratees), []);
-    props = args[1];
+});
-  }
-  return baseSortByOrder(collection, baseFlatten(props), []);
-}
 
 module.exports = sortByAll;

collection/sortByOrder.js

@@ -4,45 +4,52 @@ var baseSortByOrder = require('../internal/baseSortByOrder'),
 
 /**
  * This method is like `_.sortByAll` except that it allows specifying the
- * sort orders of the property names to sort by. A truthy value in `orders`
+ * sort orders of the iteratees to sort by. A truthy value in `orders` will
- * will sort the corresponding property name in ascending order while a
+ * sort the corresponding property name in ascending order while a falsey
- * falsey value will sort it in descending order.
+ * value will sort it in descending order.
+ *
+ * If a property name is provided for an iteratee the created `_.property`
+ * style callback returns the property value of the given element.
+ *
+ * If an object is provided for an iteratee the created `_.matches` style
+ * callback returns `true` for elements that have the properties of the given
+ * object, else `false`.
  *
  * @static
  * @memberOf _
  * @category Collection
  * @param {Array|Object|string} collection The collection to iterate over.
- * @param {string[]} props The property names to sort by.
+ * @param {Function[]|Object[]|string[]} iteratees The iteratees to sort by.
- * @param {boolean[]} orders The sort orders of `props`.
+ * @param {boolean[]} orders The sort orders of `iteratees`.
  * @param- {Object} [guard] Enables use as a callback for functions like `_.reduce`.
  * @returns {Array} Returns the new sorted array.
  * @example
  *
  * var users = [
- *   { 'user': 'barney', 'age': 26 },
+ *   { 'user': 'fred',   'age': 48 },
- *   { 'user': 'fred',   'age': 40 },
+ *   { 'user': 'barney', 'age': 34 },
- *   { 'user': 'barney', 'age': 36 },
+ *   { 'user': 'fred',   'age': 42 },
- *   { 'user': 'fred',   'age': 30 }
+ *   { 'user': 'barney', 'age': 36 }
  * ];
  *
  * // sort by `user` in ascending order and by `age` in descending order
  * _.map(_.sortByOrder(users, ['user', 'age'], [true, false]), _.values);
- * // => [['barney', 36], ['barney', 26], ['fred', 40], ['fred', 30]]
+ * // => [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 42]]
  */
-function sortByOrder(collection, props, orders, guard) {
+function sortByOrder(collection, iteratees, orders, guard) {
   if (collection == null) {
     return [];
   }
-  if (guard && isIterateeCall(props, orders, guard)) {
+  if (guard && isIterateeCall(iteratees, orders, guard)) {
     orders = null;
   }
-  if (!isArray(props)) {
+  if (!isArray(iteratees)) {
-    props = props == null ? [] : [props];
+    iteratees = iteratees == null ? [] : [iteratees];
   }
   if (!isArray(orders)) {
     orders = orders == null ? [] : [orders];
   }
-  return baseSortByOrder(collection, props, orders);
+  return baseSortByOrder(collection, iteratees, orders);
 }
 
 module.exports = sortByOrder;

function/before.js

@@ -31,7 +31,8 @@ function before(n, func) {
   return function() {
     if (--n > 0) {
       result = func.apply(this, arguments);
-    } else {
+    }
+    if (n <= 1) {
       func = null;
     }
     return result;

function/bind.js

@@ -14,7 +14,7 @@ var BIND_FLAG = 1,
  * The `_.bind.placeholder` value, which defaults to `_` in monolithic builds,
  * may be used as a placeholder for partially applied arguments.
  *
- * **Note:** Unlike native `Function#bind` this method does not set the `length`
+ * **Note:** Unlike native `Function#bind` this method does not set the "length"
  * property of bound functions.
  *
  * @static

function/bindAll.js

@@ -12,7 +12,7 @@ var BIND_FLAG = 1;
  * of method names. If no method names are provided all enumerable function
  * properties, own and inherited, of `object` are bound.
  *
- * **Note:** This method does not set the `length` property of bound functions.
+ * **Note:** This method does not set the "length" property of bound functions.
  *
  * @static
  * @memberOf _

function/bindKey.js

@@ -13,7 +13,7 @@ var BIND_FLAG = 1,
  *
  * This method differs from `_.bind` by allowing bound functions to reference
  * methods that may be redefined or don't yet exist.
- * See [Peter Michaux's article](http://michaux.ca/articles/lazy-function-definition-pattern)
+ * See [Peter Michaux's article](http://peter.michaux.ca/articles/lazy-function-definition-pattern)
  * for more details.
  *
  * The `_.bindKey.placeholder` value, which defaults to `_` in monolithic

function/curry.js

@@ -13,7 +13,7 @@ var CURRY_FLAG = 8;
  * The `_.curry.placeholder` value, which defaults to `_` in monolithic builds,
  * may be used as a placeholder for provided arguments.
  *
- * **Note:** This method does not set the `length` property of curried functions.
+ * **Note:** This method does not set the "length" property of curried functions.
  *
  * @static
  * @memberOf _

function/curryRight.js

@@ -10,7 +10,7 @@ var CURRY_RIGHT_FLAG = 16;
  * The `_.curryRight.placeholder` value, which defaults to `_` in monolithic
  * builds, may be used as a placeholder for provided arguments.
  *
- * **Note:** This method does not set the `length` property of curried functions.
+ * **Note:** This method does not set the "length" property of curried functions.
  *
  * @static
  * @memberOf _

function/once.js

@@ -18,7 +18,7 @@ var before = require('./before');
  * // `initialize` invokes `createApplication` once
  */
 function once(func) {
-  return before(func, 2);
+  return before(2, func);
 }
 
 module.exports = once;

function/partial.js

@@ -11,7 +11,7 @@ var PARTIAL_FLAG = 32;
  * The `_.partial.placeholder` value, which defaults to `_` in monolithic
  * builds, may be used as a placeholder for partially applied arguments.
  *
- * **Note:** This method does not set the `length` property of partially
+ * **Note:** This method does not set the "length" property of partially
  * applied functions.
  *
  * @static

function/partialRight.js

@@ -10,7 +10,7 @@ var PARTIAL_RIGHT_FLAG = 64;
  * The `_.partialRight.placeholder` value, which defaults to `_` in monolithic
  * builds, may be used as a placeholder for partially applied arguments.
  *
- * **Note:** This method does not set the `length` property of partially
+ * **Note:** This method does not set the "length" property of partially
  * applied functions.
  *
  * @static

function/restParam.js

@@ -30,7 +30,7 @@ function restParam(func, start) {
   if (typeof func != 'function') {
     throw new TypeError(FUNC_ERROR_TEXT);
   }
-  start = nativeMax(typeof start == 'undefined' ? (func.length - 1) : (+start || 0), 0);
+  start = nativeMax(start === undefined ? (func.length - 1) : (+start || 0), 0);
   return function() {
     var args = arguments,
         index = -1,

internal/assignDefaults.js

@@ -7,7 +7,7 @@
  * @returns {*} Returns the value to assign to the destination object.
  */
 function assignDefaults(objectValue, sourceValue) {
-  return typeof objectValue == 'undefined' ? sourceValue : objectValue;
+  return objectValue === undefined ? sourceValue : objectValue;
 }
 
 module.exports = assignDefaults;

internal/assignOwnDefaults.js

@@ -7,7 +7,7 @@ var hasOwnProperty = objectProto.hasOwnProperty;
 /**
  * Used by `_.template` to customize its `_.assign` use.
  *
- * **Note:** This method is like `assignDefaults` except that it ignores
+ * **Note:** This function is like `assignDefaults` except that it ignores
  * inherited property values when checking if a property is `undefined`.
  *
  * @private
@@ -18,7 +18,7 @@ var hasOwnProperty = objectProto.hasOwnProperty;
  * @returns {*} Returns the value to assign to the destination object.
  */
 function assignOwnDefaults(objectValue, sourceValue, key, object) {
-  return (typeof objectValue == 'undefined' || !hasOwnProperty.call(object, key))
+  return (objectValue === undefined || !hasOwnProperty.call(object, key))
     ? sourceValue
     : objectValue;
 }

internal/assignWith.js

@@ -0,0 +1,41 @@
+var getSymbols = require('./getSymbols'),
+    keys = require('../object/keys');
+
+/** Used for native method references. */
+var arrayProto = Array.prototype;
+
+/** Native method references. */
+var push = arrayProto.push;
+
+/**
+ * A specialized version of `_.assign` for customizing assigned values without
+ * support for argument juggling, multiple sources, and `this` binding `customizer`
+ * functions.
+ *
+ * @private
+ * @param {Object} object The destination object.
+ * @param {Object} source The source object.
+ * @param {Function} customizer The function to customize assigned values.
+ * @returns {Object} Returns `object`.
+ */
+function assignWith(object, source, customizer) {
+  var props = keys(source);
+  push.apply(props, getSymbols(source));
+
+  var index = -1,
+      length = props.length;
+
+  while (++index < length) {
+    var key = props[index],
+        value = object[key],
+        result = customizer(value, source[key], key, object, source);
+
+    if ((result === result ? (result !== value) : (value === value)) ||
+        (value === undefined && !(key in object))) {
+      object[key] = result;
+    }
+  }
+  return object;
+}
+
+module.exports = assignWith;

internal/baseAssign.js

@@ -1,35 +1,47 @@
 var baseCopy = require('./baseCopy'),
+    getSymbols = require('./getSymbols'),
+    isNative = require('../lang/isNative'),
     keys = require('../object/keys');
 
+/** Native method references. */
+var preventExtensions = isNative(preventExtensions = Object.preventExtensions) && preventExtensions;
+
+/** Used as `baseAssign`. */
+var nativeAssign = (function() {
+  // Avoid `Object.assign` in Firefox 34-37 which have an early implementation
+  // with a now defunct try/catch behavior. See https://bugzilla.mozilla.org/show_bug.cgi?id=1103344
+  // for more details.
+  //
+  // Use `Object.preventExtensions` on a plain object instead of simply using
+  // `Object('x')` because Chrome and IE fail to throw an error when attempting
+  // to assign values to readonly indexes of strings.
+  var func = preventExtensions && isNative(func = Object.assign) && func;
+  try {
+    if (func) {
+      var object = preventExtensions({ '1': 0 });
+      object[0] = 1;
+    }
+  } catch(e) {
+    // Only attempt in strict mode.
+    try { func(object, 'xo'); } catch(e) {}
+    return !object[1] && func;
+  }
+  return false;
+}());
+
 /**
  * The base implementation of `_.assign` without support for argument juggling,
- * multiple sources, and `this` binding `customizer` functions.
+ * multiple sources, and `customizer` functions.
  *
  * @private
  * @param {Object} object The destination object.
  * @param {Object} source The source object.
- * @param {Function} [customizer] The function to customize assigning values.
+ * @returns {Object} Returns `object`.
- * @returns {Object} Returns the destination object.
  */
-function baseAssign(object, source, customizer) {
+var baseAssign = nativeAssign || function(object, source) {
-  var props = keys(source);
+  return source == null
-  if (!customizer) {
+    ? object
-    return baseCopy(source, object, props);
+    : baseCopy(source, getSymbols(source), baseCopy(source, keys(source), object));
-  }
+};
-  var index = -1,
-      length = props.length;
-
-  while (++index < length) {
-    var key = props[index],
-        value = object[key],
-        result = customizer(value, source[key], key, object, source);
-
-    if ((result === result ? (result !== value) : (value === value)) ||
-        (typeof value == 'undefined' && !(key in object))) {
-      object[key] = result;
-    }
-  }
-  return object;
-}
 
 module.exports = baseAssign;

internal/baseAt.js

@@ -1,29 +1,29 @@
-var isIndex = require('./isIndex'),
+var isArrayLike = require('./isArrayLike'),
-    isLength = require('./isLength');
+    isIndex = require('./isIndex');
 
 /**
- * The base implementation of `_.at` without support for strings and individual
+ * The base implementation of `_.at` without support for string collections
- * key arguments.
+ * and individual key arguments.
  *
  * @private
  * @param {Array|Object} collection The collection to iterate over.
- * @param {number[]|string[]} [props] The property names or indexes of elements to pick.
+ * @param {number[]|string[]} props The property names or indexes of elements to pick.
  * @returns {Array} Returns the new array of picked elements.
  */
 function baseAt(collection, props) {
   var index = -1,
-      length = collection.length,
+      isNil = collection == null,
-      isArr = isLength(length),
+      isArr = !isNil && isArrayLike(collection),
+      length = isArr && collection.length,
       propsLength = props.length,
       result = Array(propsLength);
 
   while(++index < propsLength) {
     var key = props[index];
     if (isArr) {
-      key = parseFloat(key);
       result[index] = isIndex(key, length) ? collection[key] : undefined;
     } else {
-      result[index] = collection[key];
+      result[index] = isNil ? undefined : collection[key];
     }
   }
   return result;

internal/baseCallback.js

@@ -1,8 +1,8 @@
 var baseMatches = require('./baseMatches'),
     baseMatchesProperty = require('./baseMatchesProperty'),
-    baseProperty = require('./baseProperty'),
     bindCallback = require('./bindCallback'),
-    identity = require('../utility/identity');
+    identity = require('../utility/identity'),
+    property = require('../utility/property');
 
 /**
  * The base implementation of `_.callback` which supports specifying the
@@ -17,7 +17,7 @@ var baseMatches = require('./baseMatches'),
 function baseCallback(func, thisArg, argCount) {
   var type = typeof func;
   if (type == 'function') {
-    return typeof thisArg == 'undefined'
+    return thisArg === undefined
       ? func
       : bindCallback(func, thisArg, argCount);
   }
@@ -27,9 +27,9 @@ function baseCallback(func, thisArg, argCount) {
   if (type == 'object') {
     return baseMatches(func);
   }
-  return typeof thisArg == 'undefined'
+  return thisArg === undefined
-    ? baseProperty(func + '')
+    ? property(func)
-    : baseMatchesProperty(func + '', thisArg);
+    : baseMatchesProperty(func, thisArg);
 }
 
 module.exports = baseCallback;

internal/baseClone.js

@@ -1,13 +1,12 @@
 var arrayCopy = require('./arrayCopy'),
     arrayEach = require('./arrayEach'),
-    baseCopy = require('./baseCopy'),
+    baseAssign = require('./baseAssign'),
     baseForOwn = require('./baseForOwn'),
     initCloneArray = require('./initCloneArray'),
     initCloneByTag = require('./initCloneByTag'),
     initCloneObject = require('./initCloneObject'),
     isArray = require('../lang/isArray'),
-    isObject = require('../lang/isObject'),
+    isObject = require('../lang/isObject');
-    keys = require('../object/keys');
 
 /** `Object#toString` result references. */
 var argsTag = '[object Arguments]',
@@ -78,7 +77,7 @@ function baseClone(value, isDeep, customizer, key, object, stackA, stackB) {
   if (customizer) {
     result = object ? customizer(value, key, object) : customizer(value);
   }
-  if (typeof result != 'undefined') {
+  if (result !== undefined) {
     return result;
   }
   if (!isObject(value)) {
@@ -97,7 +96,7 @@ function baseClone(value, isDeep, customizer, key, object, stackA, stackB) {
     if (tag == objectTag || tag == argsTag || (isFunc && !object)) {
       result = initCloneObject(isFunc ? {} : value);
       if (!isDeep) {
-        return baseCopy(value, result, keys(value));
+        return baseAssign(result, value);
       }
     } else {
       return cloneableTags[tag]

internal/baseCompareAscending.js

@@ -12,10 +12,10 @@ function baseCompareAscending(value, other) {
     var valIsReflexive = value === value,
         othIsReflexive = other === other;
 
-    if (value > other || !valIsReflexive || (typeof value == 'undefined' && othIsReflexive)) {
+    if (value > other || !valIsReflexive || (value === undefined && othIsReflexive)) {
       return 1;
     }
-    if (value < other || !othIsReflexive || (typeof other == 'undefined' && valIsReflexive)) {
+    if (value < other || !othIsReflexive || (other === undefined && valIsReflexive)) {
       return -1;
     }
   }

internal/baseCopy.js

@@ -1,17 +1,15 @@
 /**
- * Copies the properties of `source` to `object`.
+ * Copies properties of `source` to `object`.
  *
  * @private
  * @param {Object} source The object to copy properties from.
- * @param {Object} [object={}] The object to copy properties to.
  * @param {Array} props The property names to copy.
+ * @param {Object} [object={}] The object to copy properties to.
  * @returns {Object} Returns `object`.
  */
-function baseCopy(source, object, props) {
+function baseCopy(source, props, object) {
-  if (!props) {
+  object || (object = {});
-    props = object;
+
-    object = {};
-  }
   var index = -1,
       length = props.length;
 

internal/baseFill.js

@@ -15,7 +15,7 @@ function baseFill(array, value, start, end) {
   if (start < 0) {
     start = -start > length ? 0 : (length + start);
   }
-  end = (typeof end == 'undefined' || end > length) ? length : (+end || 0);
+  end = (end === undefined || end > length) ? length : (+end || 0);
   if (end < 0) {
     end += length;
   }

internal/baseFlatten.js

@@ -1,6 +1,6 @@
 var isArguments = require('../lang/isArguments'),
     isArray = require('../lang/isArray'),
-    isLength = require('./isLength'),
+    isArrayLike = require('./isArrayLike'),
     isObjectLike = require('./isObjectLike');
 
 /**
@@ -9,8 +9,8 @@ var isArguments = require('../lang/isArguments'),
  *
  * @private
  * @param {Array} array The array to flatten.
- * @param {boolean} isDeep Specify a deep flatten.
+ * @param {boolean} [isDeep] Specify a deep flatten.
- * @param {boolean} isStrict Restrict flattening to arrays and `arguments` objects.
+ * @param {boolean} [isStrict] Restrict flattening to arrays-like objects.
  * @returns {Array} Returns the new flattened array.
  */
 function baseFlatten(array, isDeep, isStrict) {
@@ -21,8 +21,8 @@ function baseFlatten(array, isDeep, isStrict) {
 
   while (++index < length) {
     var value = array[index];
-
+    if (isObjectLike(value) && isArrayLike(value) &&
-    if (isObjectLike(value) && isLength(value.length) && (isArray(value) || isArguments(value))) {
+        (isStrict || isArray(value) || isArguments(value))) {
       if (isDeep) {
         // Recursively flatten arrays (susceptible to call stack limits).
         value = baseFlatten(value, isDeep, isStrict);
@@ -30,7 +30,6 @@ function baseFlatten(array, isDeep, isStrict) {
       var valIndex = -1,
           valLength = value.length;
 
-      result.length += valLength;
       while (++valIndex < valLength) {
         result[++resIndex] = value[valIndex];
       }

internal/baseFor.js

@@ -3,7 +3,7 @@ var createBaseFor = require('./createBaseFor');
 /**
  * The base implementation of `baseForIn` and `baseForOwn` which iterates
  * over `object` properties returned by `keysFunc` invoking `iteratee` for
- * each property. Iterator functions may exit iteration early by explicitly
+ * each property. Iteratee functions may exit iteration early by explicitly
  * returning `false`.
  *
  * @private

internal/baseGet.js

@@ -0,0 +1,29 @@
+var toObject = require('./toObject');
+
+/**
+ * The base implementation of `get` without support for string paths
+ * and default values.
+ *
+ * @private
+ * @param {Object} object The object to query.
+ * @param {Array} path The path of the property to get.
+ * @param {string} [pathKey] The key representation of path.
+ * @returns {*} Returns the resolved value.
+ */
+function baseGet(object, path, pathKey) {
+  if (object == null) {
+    return;
+  }
+  if (pathKey !== undefined && pathKey in toObject(object)) {
+    path = [pathKey];
+  }
+  var index = -1,
+      length = path.length;
+
+  while (object != null && ++index < length) {
+    object = object[path[index]];
+  }
+  return (index && index == length) ? object : undefined;
+}
+
+module.exports = baseGet;

internal/baseIsEqual.js

@@ -16,8 +16,7 @@ var baseIsEqualDeep = require('./baseIsEqualDeep');
 function baseIsEqual(value, other, customizer, isLoose, stackA, stackB) {
   // Exit early for identical values.
   if (value === other) {
-    // Treat `+0` vs. `-0` as not equal.
+    return true;
-    return value !== 0 || (1 / value == 1 / other);
   }
   var valType = typeof value,
       othType = typeof other;

internal/baseIsEqualDeep.js

@@ -7,7 +7,6 @@ var equalArrays = require('./equalArrays'),
 /** `Object#toString` result references. */
 var argsTag = '[object Arguments]',
     arrayTag = '[object Array]',
-    funcTag = '[object Function]',
     objectTag = '[object Object]';
 
 /** Used for native method references. */
@@ -59,27 +58,23 @@ function baseIsEqualDeep(object, other, equalFunc, customizer, isLoose, stackA,
       othIsArr = isTypedArray(other);
     }
   }
-  var objIsObj = (objTag == objectTag || (isLoose && objTag == funcTag)),
+  var objIsObj = objTag == objectTag,
-      othIsObj = (othTag == objectTag || (isLoose && othTag == funcTag)),
+      othIsObj = othTag == objectTag,
       isSameTag = objTag == othTag;
 
   if (isSameTag && !(objIsArr || objIsObj)) {
     return equalByTag(object, other, objTag);
   }
-  if (isLoose) {
+  if (!isLoose) {
-    if (!isSameTag && !(objIsObj && othIsObj)) {
-      return false;
-    }
-  } else {
     var valWrapped = objIsObj && hasOwnProperty.call(object, '__wrapped__'),
         othWrapped = othIsObj && hasOwnProperty.call(other, '__wrapped__');
 
     if (valWrapped || othWrapped) {
       return equalFunc(valWrapped ? object.value() : object, othWrapped ? other.value() : other, customizer, isLoose, stackA, stackB);
     }
-    if (!isSameTag) {
+  }
-      return false;
+  if (!isSameTag) {
-    }
+    return false;
   }
   // Assume cyclic values are equal.
   // For more information on detecting circular references see https://es5.github.io/#JO.

internal/baseIsMatch.js

@@ -32,10 +32,10 @@ function baseIsMatch(object, props, values, strictCompareFlags, customizer) {
         srcValue = values[index];
 
     if (noCustomizer && strictCompareFlags[index]) {
-      var result = typeof objValue != 'undefined' || (key in object);
+      var result = objValue !== undefined || (key in object);
     } else {
       result = customizer ? customizer(objValue, srcValue, key) : undefined;
-      if (typeof result == 'undefined') {
+      if (result === undefined) {
         result = baseIsEqual(srcValue, objValue, customizer, true);
       }
     }

internal/baseMap.js

@@ -1,4 +1,5 @@
-var baseEach = require('./baseEach');
+var baseEach = require('./baseEach'),
+    isArrayLike = require('./isArrayLike');
 
 /**
  * The base implementation of `_.map` without support for callback shorthands
@@ -10,9 +11,11 @@ var baseEach = require('./baseEach');
  * @returns {Array} Returns the new mapped array.
  */
 function baseMap(collection, iteratee) {
-  var result = [];
+  var index = -1,
+      result = isArrayLike(collection) ? Array(collection.length) : [];
+
   baseEach(collection, function(value, key, collection) {
-    result.push(iteratee(value, key, collection));
+    result[++index] = iteratee(value, key, collection);
   });
   return result;
 }

internal/baseMatches.js

@@ -24,8 +24,10 @@ function baseMatches(source) {
 
     if (isStrictComparable(value)) {
       return function(object) {
-        return object != null && object[key] === value &&
+        if (object == null) {
-          (typeof value != 'undefined' || (key in toObject(object)));
+          return false;
+        }
+        return object[key] === value && (value !== undefined || (key in toObject(object)));
       };
     }
   }

internal/baseMatchesProperty.js

@@ -1,25 +1,45 @@
-var baseIsEqual = require('./baseIsEqual'),
+var baseGet = require('./baseGet'),
+    baseIsEqual = require('./baseIsEqual'),
+    baseSlice = require('./baseSlice'),
+    isArray = require('../lang/isArray'),
+    isKey = require('./isKey'),
     isStrictComparable = require('./isStrictComparable'),
-    toObject = require('./toObject');
+    last = require('../array/last'),
+    toObject = require('./toObject'),
+    toPath = require('./toPath');
 
 /**
- * The base implementation of `_.matchesProperty` which does not coerce `key`
+ * The base implementation of `_.matchesProperty` which does not which does
- * to a string.
+ * not clone `value`.
  *
  * @private
- * @param {string} key The key of the property to get.
+ * @param {string} path The path of the property to get.
  * @param {*} value The value to compare.
  * @returns {Function} Returns the new function.
  */
-function baseMatchesProperty(key, value) {
+function baseMatchesProperty(path, value) {
-  if (isStrictComparable(value)) {
+  var isArr = isArray(path),
-    return function(object) {
+      isCommon = isKey(path) && isStrictComparable(value),
-      return object != null && object[key] === value &&
+      pathKey = (path + '');
-        (typeof value != 'undefined' || (key in toObject(object)));
+
-    };
+  path = toPath(path);
-  }
   return function(object) {
-    return object != null && baseIsEqual(value, object[key], null, true);
+    if (object == null) {
+      return false;
+    }
+    var key = pathKey;
+    object = toObject(object);
+    if ((isArr || !isCommon) && !(key in object)) {
+      object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
+      if (object == null) {
+        return false;
+      }
+      key = last(path);
+      object = toObject(object);
+    }
+    return object[key] === value
+      ? (value !== undefined || (key in object))
+      : baseIsEqual(value, object[key], null, true);
   };
 }
 

internal/baseMerge.js

@@ -1,11 +1,18 @@
 var arrayEach = require('./arrayEach'),
-    baseForOwn = require('./baseForOwn'),
     baseMergeDeep = require('./baseMergeDeep'),
+    getSymbols = require('./getSymbols'),
     isArray = require('../lang/isArray'),
-    isLength = require('./isLength'),
+    isArrayLike = require('./isArrayLike'),
     isObject = require('../lang/isObject'),
     isObjectLike = require('./isObjectLike'),
-    isTypedArray = require('../lang/isTypedArray');
+    isTypedArray = require('../lang/isTypedArray'),
+    keys = require('../object/keys');
+
+/** Used for native method references. */
+var arrayProto = Array.prototype;
+
+/** Native method references. */
+var push = arrayProto.push;
 
 /**
  * The base implementation of `_.merge` without support for argument juggling,
@@ -17,29 +24,39 @@ var arrayEach = require('./arrayEach'),
  * @param {Function} [customizer] The function to customize merging properties.
  * @param {Array} [stackA=[]] Tracks traversed source objects.
  * @param {Array} [stackB=[]] Associates values with source counterparts.
- * @returns {Object} Returns the destination object.
+ * @returns {Object} Returns `object`.
  */
 function baseMerge(object, source, customizer, stackA, stackB) {
   if (!isObject(object)) {
     return object;
   }
-  var isSrcArr = isLength(source.length) && (isArray(source) || isTypedArray(source));
+  var isSrcArr = isArrayLike(source) && (isArray(source) || isTypedArray(source));
-  (isSrcArr ? arrayEach : baseForOwn)(source, function(srcValue, key, source) {
+  if (!isSrcArr) {
+    var props = keys(source);
+    push.apply(props, getSymbols(source));
+  }
+  arrayEach(props || source, function(srcValue, key) {
+    if (props) {
+      key = srcValue;
+      srcValue = source[key];
+    }
     if (isObjectLike(srcValue)) {
       stackA || (stackA = []);
       stackB || (stackB = []);
-      return baseMergeDeep(object, source, key, baseMerge, customizer, stackA, stackB);
+      baseMergeDeep(object, source, key, baseMerge, customizer, stackA, stackB);
     }
-    var value = object[key],
+    else {
-        result = customizer ? customizer(value, srcValue, key, object, source) : undefined,
+      var value = object[key],
-        isCommon = typeof result == 'undefined';
+          result = customizer ? customizer(value, srcValue, key, object, source) : undefined,
+          isCommon = result === undefined;
 
-    if (isCommon) {
+      if (isCommon) {
-      result = srcValue;
+        result = srcValue;
-    }
+      }
-    if ((isSrcArr || typeof result != 'undefined') &&
+      if ((isSrcArr || result !== undefined) &&
-        (isCommon || (result === result ? (result !== value) : (value === value)))) {
+          (isCommon || (result === result ? (result !== value) : (value === value)))) {
-      object[key] = result;
+        object[key] = result;
+      }
     }
   });
   return object;

internal/baseMergeDeep.js

@@ -1,7 +1,7 @@
 var arrayCopy = require('./arrayCopy'),
     isArguments = require('../lang/isArguments'),
     isArray = require('../lang/isArray'),
-    isLength = require('./isLength'),
+    isArrayLike = require('./isArrayLike'),
     isPlainObject = require('../lang/isPlainObject'),
     isTypedArray = require('../lang/isTypedArray'),
     toPlainObject = require('../lang/toPlainObject');
@@ -33,14 +33,14 @@ function baseMergeDeep(object, source, key, mergeFunc, customizer, stackA, stack
   }
   var value = object[key],
       result = customizer ? customizer(value, srcValue, key, object, source) : undefined,
-      isCommon = typeof result == 'undefined';
+      isCommon = result === undefined;
 
   if (isCommon) {
     result = srcValue;
-    if (isLength(srcValue.length) && (isArray(srcValue) || isTypedArray(srcValue))) {
+    if (isArrayLike(srcValue) && (isArray(srcValue) || isTypedArray(srcValue))) {
       result = isArray(value)
         ? value
-        : ((value && value.length) ? arrayCopy(value) : []);
+        : (isArrayLike(value) ? arrayCopy(value) : []);
     }
     else if (isPlainObject(srcValue) || isArguments(srcValue)) {
       result = isArguments(value)

internal/baseProperty.js

@@ -1,5 +1,5 @@
 /**
- * The base implementation of `_.property` which does not coerce `key` to a string.
+ * The base implementation of `_.property` without support for deep paths.
  *
  * @private
  * @param {string} key The key of the property to get.

internal/basePropertyDeep.js

@@ -0,0 +1,19 @@
+var baseGet = require('./baseGet'),
+    toPath = require('./toPath');
+
+/**
+ * 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) {
+  var pathKey = (path + '');
+  path = toPath(path);
+  return function(object) {
+    return baseGet(object, path, pathKey);
+  };
+}
+
+module.exports = basePropertyDeep;

internal/basePullAt.js

@@ -0,0 +1,30 @@
+var isIndex = require('./isIndex');
+
+/** Used for native method references. */
+var arrayProto = Array.prototype;
+
+/** Native method references. */
+var splice = arrayProto.splice;
+
+/**
+ * The base implementation of `_.pullAt` without support for individual
+ * index arguments and capturing the removed elements.
+ *
+ * @private
+ * @param {Array} array The array to modify.
+ * @param {number[]} indexes The indexes of elements to remove.
+ * @returns {Array} Returns `array`.
+ */
+function basePullAt(array, indexes) {
+  var length = array ? indexes.length : 0;
+  while (length--) {
+    var index = parseFloat(indexes[length]);
+    if (index != previous && isIndex(index)) {
+      var previous = index;
+      splice.call(array, index, 1);
+    }
+  }
+  return array;
+}
+
+module.exports = basePullAt;

internal/baseSlice.js

@@ -15,7 +15,7 @@ function baseSlice(array, start, end) {
   if (start < 0) {
     start = -start > length ? 0 : (length + start);
   }
-  end = (typeof end == 'undefined' || end > length) ? length : (+end || 0);
+  end = (end === undefined || end > length) ? length : (+end || 0);
   if (end < 0) {
     end += length;
   }

internal/baseSortByOrder.js

@@ -1,30 +1,26 @@
-var baseEach = require('./baseEach'),
+var arrayMap = require('./arrayMap'),
+    baseCallback = require('./baseCallback'),
+    baseMap = require('./baseMap'),
     baseSortBy = require('./baseSortBy'),
-    compareMultiple = require('./compareMultiple'),
+    compareMultiple = require('./compareMultiple');
-    isLength = require('./isLength');
 
 /**
  * The base implementation of `_.sortByOrder` without param guards.
  *
  * @private
  * @param {Array|Object|string} collection The collection to iterate over.
- * @param {string[]} props The property names to sort by.
+ * @param {Function[]|Object[]|string[]} iteratees The iteratees to sort by.
- * @param {boolean[]} orders The sort orders of `props`.
+ * @param {boolean[]} orders The sort orders of `iteratees`.
  * @returns {Array} Returns the new sorted array.
  */
-function baseSortByOrder(collection, props, orders) {
+function baseSortByOrder(collection, iteratees, orders) {
-  var index = -1,
+  var index = -1;
-      length = collection.length,
-      result = isLength(length) ? Array(length) : [];
 
-  baseEach(collection, function(value) {
+  iteratees = arrayMap(iteratees, function(iteratee) { return baseCallback(iteratee); });
-    var length = props.length,
-        criteria = Array(length);
 
-    while (length--) {
+  var result = baseMap(collection, function(value) {
-      criteria[length] = value == null ? undefined : value[props[length]];
+    var criteria = arrayMap(iteratees, function(iteratee) { return iteratee(value); });
-    }
+    return { 'criteria': criteria, 'index': ++index, 'value': value };
-    result[++index] = { 'criteria': criteria, 'index': index, 'value': value };
   });
 
   return baseSortBy(result, function(object, other) {

internal/baseValues.js

@@ -1,7 +1,7 @@
 /**
  * The base implementation of `_.values` and `_.valuesIn` which creates an
  * array of `object` property values corresponding to the property names
- * returned by `keysFunc`.
+ * of `props`.
  *
  * @private
  * @param {Object} object The object to query.

internal/binaryIndexBy.js

@@ -6,7 +6,7 @@ var nativeMin = Math.min;
 
 /** Used as references for the maximum length and index of an array. */
 var MAX_ARRAY_LENGTH = Math.pow(2, 32) - 1,
-    MAX_ARRAY_INDEX =  MAX_ARRAY_LENGTH - 1;
+    MAX_ARRAY_INDEX = MAX_ARRAY_LENGTH - 1;
 
 /**
  * This function is like `binaryIndex` except that it invokes `iteratee` for
@@ -27,7 +27,7 @@ function binaryIndexBy(array, value, iteratee, retHighest) {
   var low = 0,
       high = array ? array.length : 0,
       valIsNaN = value !== value,
-      valIsUndef = typeof value == 'undefined';
+      valIsUndef = value === undefined;
 
   while (low < high) {
     var mid = floor((low + high) / 2),
@@ -37,7 +37,7 @@ function binaryIndexBy(array, value, iteratee, retHighest) {
     if (valIsNaN) {
       var setLow = isReflexive || retHighest;
     } else if (valIsUndef) {
-      setLow = isReflexive && (retHighest || typeof computed != 'undefined');
+      setLow = isReflexive && (retHighest || computed !== undefined);
     } else {
       setLow = retHighest ? (computed <= value) : (computed < value);
     }

internal/bindCallback.js

@@ -14,7 +14,7 @@ function bindCallback(func, thisArg, argCount) {
   if (typeof func != 'function') {
     return identity;
   }
-  if (typeof thisArg == 'undefined') {
+  if (thisArg === undefined) {
     return func;
   }
   switch (argCount) {

internal/compareMultiple.js

@@ -4,7 +4,7 @@ var baseCompareAscending = require('./baseCompareAscending');
  * Used by `_.sortByOrder` to compare multiple properties of each element
  * in a collection and stable sort them in the following order:
  *
- * If orders is unspecified, sort in ascending order for all properties.
+ * If `orders` is unspecified, sort in ascending order for all properties.
  * Otherwise, for each property, sort in ascending order if its corresponding value in
  * orders is true, and descending order if false.
  *

internal/composeArgsRight.js

@@ -23,12 +23,12 @@ function composeArgsRight(args, partials, holders) {
   while (++argsIndex < argsLength) {
     result[argsIndex] = args[argsIndex];
   }
-  var pad = argsIndex;
+  var offset = argsIndex;
   while (++rightIndex < rightLength) {
-    result[pad + rightIndex] = partials[rightIndex];
+    result[offset + rightIndex] = partials[rightIndex];
   }
   while (++holdersIndex < holdersLength) {
-    result[pad + holders[holdersIndex]] = args[argsIndex++];
+    result[offset + holders[holdersIndex]] = args[argsIndex++];
   }
   return result;
 }

internal/createAssigner.js

@@ -1,5 +1,6 @@
 var bindCallback = require('./bindCallback'),
-    isIterateeCall = require('./isIterateeCall');
+    isIterateeCall = require('./isIterateeCall'),
+    restParam = require('../function/restParam');
 
 /**
  * Creates a function that assigns properties of source object(s) to a given
@@ -12,38 +13,32 @@ var bindCallback = require('./bindCallback'),
  * @returns {Function} Returns the new assigner function.
  */
 function createAssigner(assigner) {
-  return function() {
+  return restParam(function(object, sources) {
-    var args = arguments,
+    var index = -1,
-        length = args.length,
+        length = object == null ? 0 : sources.length,
-        object = args[0];
+        customizer = length > 2 && sources[length - 2],
+        guard = length > 2 && sources[2],
+        thisArg = length > 1 && sources[length - 1];
 
-    if (length < 2 || object == null) {
+    if (typeof customizer == 'function') {
-      return object;
-    }
-    var customizer = args[length - 2],
-        thisArg = args[length - 1],
-        guard = args[3];
-
-    if (length > 3 && typeof customizer == 'function') {
       customizer = bindCallback(customizer, thisArg, 5);
       length -= 2;
     } else {
-      customizer = (length > 2 && typeof thisArg == 'function') ? thisArg : null;
+      customizer = typeof thisArg == 'function' ? thisArg : null;
       length -= (customizer ? 1 : 0);
     }
-    if (guard && isIterateeCall(args[1], args[2], guard)) {
+    if (guard && isIterateeCall(sources[0], sources[1], guard)) {
-      customizer = length == 3 ? null : customizer;
+      customizer = length < 3 ? null : customizer;
-      length = 2;
+      length = 1;
     }
-    var index = 0;
     while (++index < length) {
-      var source = args[index];
+      var source = sources[index];
       if (source) {
         assigner(object, source, customizer);
       }
     }
     return object;
-  };
+  });
 }
 
 module.exports = createAssigner;

internal/createBaseEach.js

@@ -1,4 +1,5 @@
-var isLength = require('./isLength'),
+var getLength = require('./getLength'),
+    isLength = require('./isLength'),
     toObject = require('./toObject');
 
 /**
@@ -11,7 +12,7 @@ var isLength = require('./isLength'),
  */
 function createBaseEach(eachFunc, fromRight) {
   return function(collection, iteratee) {
-    var length = collection ? collection.length : 0;
+    var length = collection ? getLength(collection) : 0;
     if (!isLength(length)) {
       return eachFunc(collection, iteratee);
     }

internal/createFind.js

@@ -19,7 +19,7 @@ function createFind(eachFunc, fromRight) {
       return index > -1 ? collection[index] : undefined;
     }
     return baseFind(collection, predicate, eachFunc);
-  }
+  };
 }
 
 module.exports = createFind;

internal/createFlow.js

@@ -4,6 +4,12 @@ var LodashWrapper = require('./LodashWrapper'),
     isArray = require('../lang/isArray'),
     isLaziable = require('./isLaziable');
 
+/** Used to compose bitmasks for wrapper metadata. */
+var CURRY_FLAG = 8,
+    PARTIAL_FLAG = 32,
+    ARY_FLAG = 128,
+    REARG_FLAG = 256;
+
 /** Used as the `TypeError` message for "Functions" methods. */
 var FUNC_ERROR_TEXT = 'Expected a function';
 
@@ -39,7 +45,7 @@ function createFlow(fromRight) {
       funcName = getFuncName(func);
 
       var data = funcName == 'wrapper' ? getData(func) : null;
-      if (data && isLaziable(data[0])) {
+      if (data && isLaziable(data[0]) && data[1] == (ARY_FLAG | CURRY_FLAG | PARTIAL_FLAG | REARG_FLAG) && !data[4].length && data[9] == 1) {
         wrapper = wrapper[getFuncName(data[0])].apply(wrapper, data[3]);
       } else {
         wrapper = (func.length == 1 && isLaziable(func)) ? wrapper[funcName]() : wrapper.thru(func);

internal/createForEach.js

@@ -11,7 +11,7 @@ var bindCallback = require('./bindCallback'),
  */
 function createForEach(arrayFunc, eachFunc) {
   return function(collection, iteratee, thisArg) {
-    return (typeof iteratee == 'function' && typeof thisArg == 'undefined' && isArray(collection))
+    return (typeof iteratee == 'function' && thisArg === undefined && isArray(collection))
       ? arrayFunc(collection, iteratee)
       : eachFunc(collection, bindCallback(iteratee, thisArg, 3));
   };

internal/createForIn.js

@@ -10,7 +10,7 @@ var bindCallback = require('./bindCallback'),
  */
 function createForIn(objectFunc) {
   return function(object, iteratee, thisArg) {
-    if (typeof iteratee != 'function' || typeof thisArg != 'undefined') {
+    if (typeof iteratee != 'function' || thisArg !== undefined) {
       iteratee = bindCallback(iteratee, thisArg, 3);
     }
     return objectFunc(object, iteratee, keysIn);

internal/createForOwn.js

@@ -9,7 +9,7 @@ var bindCallback = require('./bindCallback');
  */
 function createForOwn(objectFunc) {
   return function(object, iteratee, thisArg) {
-    if (typeof iteratee != 'function' || typeof thisArg != 'undefined') {
+    if (typeof iteratee != 'function' || thisArg !== undefined) {
       iteratee = bindCallback(iteratee, thisArg, 3);
     }
     return objectFunc(object, iteratee);

internal/createObjectMapper.js

@@ -0,0 +1,26 @@
+var baseCallback = require('./baseCallback'),
+    baseForOwn = require('./baseForOwn');
+
+/**
+ * Creates a function for `_.mapKeys` or `_.mapValues`.
+ *
+ * @private
+ * @param {boolean} [isMapKeys] Specify mapping keys instead of values.
+ * @returns {Function} Returns the new map function.
+ */
+function createObjectMapper(isMapKeys) {
+  return function(object, iteratee, thisArg) {
+    var result = {};
+    iteratee = baseCallback(iteratee, thisArg, 3);
+
+    baseForOwn(object, function(value, key, object) {
+      var mapped = iteratee(value, key, object);
+      key = isMapKeys ? mapped : key;
+      value = isMapKeys ? value : mapped;
+      result[key] = value;
+    });
+    return result;
+  };
+}
+
+module.exports = createObjectMapper;

internal/createPadDir.js

@@ -11,7 +11,7 @@ var baseToString = require('./baseToString'),
 function createPadDir(fromRight) {
   return function(string, length, chars) {
     string = baseToString(string);
-    return string && ((fromRight ? string : '') + createPadding(string, length, chars) + (fromRight ? '' : string));
+    return (fromRight ? string : '') + createPadding(string, length, chars) + (fromRight ? '' : string);
   };
 }
 

internal/createReduce.js

@@ -13,7 +13,7 @@ var baseCallback = require('./baseCallback'),
 function createReduce(arrayFunc, eachFunc) {
   return function(collection, iteratee, accumulator, thisArg) {
     var initFromArray = arguments.length < 3;
-    return (typeof iteratee == 'function' && typeof thisArg == 'undefined' && isArray(collection))
+    return (typeof iteratee == 'function' && thisArg === undefined && isArray(collection))
       ? arrayFunc(collection, iteratee, accumulator, initFromArray)
       : baseReduce(collection, baseCallback(iteratee, thisArg, 4), accumulator, initFromArray, eachFunc);
   };

internal/equalArrays.js

@@ -32,7 +32,7 @@ function equalArrays(array, other, equalFunc, customizer, isLoose, stackA, stack
         ? customizer(othValue, arrValue, index)
         : customizer(arrValue, othValue, index);
     }
-    if (typeof result == 'undefined') {
+    if (result === undefined) {
       // Recursively compare arrays (susceptible to call stack limits).
       if (isLoose) {
         var othIndex = othLength;

internal/equalByTag.js

@@ -34,8 +34,7 @@ function equalByTag(object, other, tag) {
       // Treat `NaN` vs. `NaN` as equal.
       return (object != +object)
         ? other != +other
-        // But, treat `-0` vs. `+0` as not equal.
+        : object == +other;
-        : (object == 0 ? ((1 / object) == (1 / other)) : object == +other);
 
     case regexpTag:
     case stringTag:

internal/equalObjects.js

@@ -46,7 +46,7 @@ function equalObjects(object, other, equalFunc, customizer, isLoose, stackA, sta
           ? customizer(othValue, objValue, key)
           : customizer(objValue, othValue, key);
       }
-      if (typeof result == 'undefined') {
+      if (result === undefined) {
         // Recursively compare objects (susceptible to call stack limits).
         result = (objValue && objValue === othValue) || equalFunc(objValue, othValue, customizer, isLoose, stackA, stackB);
       }

internal/getLength.js

@@ -0,0 +1,15 @@
+var baseProperty = require('./baseProperty');
+
+/**
+ * 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');
+
+module.exports = getLength;

internal/getSymbols.js

@@ -0,0 +1,19 @@
+var constant = require('../utility/constant'),
+    isNative = require('../lang/isNative'),
+    toObject = require('./toObject');
+
+/** Native method references. */
+var getOwnPropertySymbols = isNative(getOwnPropertySymbols = Object.getOwnPropertySymbols) && getOwnPropertySymbols;
+
+/**
+ * Creates an array of the own symbols of `object`.
+ *
+ * @private
+ * @param {Object} object The object to query.
+ * @returns {Array} Returns the array of symbols.
+ */
+var getSymbols = !getOwnPropertySymbols ? constant([]) : function(object) {
+  return getOwnPropertySymbols(toObject(object));
+};
+
+module.exports = getSymbols;

internal/initCloneByTag.js

@@ -27,7 +27,6 @@ var reFlags = /\w*$/;
  * **Note:** This function only supports cloning values with tags of
  * `Boolean`, `Date`, `Error`, `Number`, `RegExp`, or `String`.
  *
- *
  * @private
  * @param {Object} object The object to clone.
  * @param {string} tag The `toStringTag` of the object to clone.

internal/invokePath.js

@@ -0,0 +1,26 @@
+var baseGet = require('./baseGet'),
+    baseSlice = require('./baseSlice'),
+    isKey = require('./isKey'),
+    last = require('../array/last'),
+    toPath = require('./toPath');
+
+/**
+ * Invokes the method at `path` on `object`.
+ *
+ * @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 invokePath(object, path, args) {
+  if (object != null && !isKey(path, object)) {
+    path = toPath(path);
+    object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
+    path = last(path);
+  }
+  var func = object == null ? object : object[path];
+  return func == null ? undefined : func.apply(object, args);
+}
+
+module.exports = invokePath;

internal/isArrayLike.js

@@ -0,0 +1,15 @@
+var getLength = require('./getLength'),
+    isLength = require('./isLength');
+
+/**
+ * Checks if `value` is array-like.
+ *
+ * @private
+ * @param {*} value The value to check.
+ * @returns {boolean} Returns `true` if `value` is array-like, else `false`.
+ */
+function isArrayLike(value) {
+  return value != null && isLength(getLength(value));
+}
+
+module.exports = isArrayLike;

internal/isIterateeCall.js

@@ -1,5 +1,5 @@
-var isIndex = require('./isIndex'),
+var isArrayLike = require('./isArrayLike'),
-    isLength = require('./isLength'),
+    isIndex = require('./isIndex'),
     isObject = require('../lang/isObject');
 
 /**
@@ -16,13 +16,9 @@ function isIterateeCall(value, index, object) {
     return false;
   }
   var type = typeof index;
-  if (type == 'number') {
+  if (type == 'number'
-    var length = object.length,
+      ? (isArrayLike(object) && isIndex(index, object.length))
-        prereq = isLength(length) && isIndex(index, length);
+      : (type == 'string' && index in object)) {
-  } else {
-    prereq = type == 'string' && index in object;
-  }
-  if (prereq) {
     var other = object[index];
     return value === value ? (value === other) : (other !== other);
   }

internal/isKey.js

@@ -0,0 +1,28 @@
+var isArray = require('../lang/isArray'),
+    toObject = require('./toObject');
+
+/** Used to match property names within property paths. */
+var reIsDeepProp = /\.|\[(?:[^[\]]*|(["'])(?:(?!\1)[^\n\\]|\\.)*?\1)\]/,
+    reIsPlainProp = /^\w*$/;
+
+/**
+ * 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) {
+  var type = typeof value;
+  if ((type == 'string' && reIsPlainProp.test(value)) || type == 'number') {
+    return true;
+  }
+  if (isArray(value)) {
+    return false;
+  }
+  var result = !reIsDeepProp.test(value);
+  return result || (object != null && value in toObject(object));
+}
+
+module.exports = isKey;

internal/isStrictComparable.js

@@ -9,7 +9,7 @@ var isObject = require('../lang/isObject');
  *  equality comparisons, else `false`.
  */
 function isStrictComparable(value) {
-  return value === value && (value === 0 ? ((1 / value) > 0) : !isObject(value));
+  return value === value && !isObject(value);
 }
 
 module.exports = isStrictComparable;

internal/mapSet.js

@@ -1,5 +1,5 @@
 /**
- * Adds `value` to `key` of the cache.
+ * Sets `value` to `key` of the cache.
  *
  * @private
  * @name set

internal/pickByArray.js

@@ -1,8 +1,8 @@
 var toObject = require('./toObject');
 
 /**
- * A specialized version of `_.pick` that picks `object` properties specified
+ * A specialized version of `_.pick` which picks `object` properties specified
- * by the `props` array.
+ * by `props`.
  *
  * @private
  * @param {Object} object The source object.

internal/pickByCallback.js

@@ -1,7 +1,7 @@
 var baseForIn = require('./baseForIn');
 
 /**
- * A specialized version of `_.pick` that picks `object` properties `predicate`
+ * A specialized version of `_.pick` which picks `object` properties `predicate`
  * returns truthy for.
  *
  * @private

internal/shimIsPlainObject.js

@@ -44,7 +44,7 @@ function shimIsPlainObject(value) {
   baseForIn(value, function(subValue, key) {
     result = key;
   });
-  return typeof result == 'undefined' || hasOwnProperty.call(value, result);
+  return result === undefined || hasOwnProperty.call(value, result);
 }
 
 module.exports = shimIsPlainObject;

internal/shimKeys.js

@@ -16,7 +16,7 @@ var hasOwnProperty = objectProto.hasOwnProperty;
  * own enumerable property names of `object`.
  *
  * @private
- * @param {Object} object The object to inspect.
+ * @param {Object} object The object to query.
  * @returns {Array} Returns the array of property names.
  */
 function shimKeys(object) {