Bump to v3.10.0.

README.md

@@ -1,4 +1,4 @@
-# lodash v3.7.0
+# lodash v3.10.0
 
 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/3.7.0-npm) for more details.
+See the [package source](https://github.com/lodash/lodash/tree/3.10.0-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>
@@ -39,15 +39,14 @@ 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/3.7.0-amd) & [compatibility](https://github.com/lodash/lodash-compat/tree/3.7.0-amd) builds
- * ES modules for the [modern](https://github.com/lodash/lodash/tree/3.7.0-es) build
+ * AMD modules for [modern](https://github.com/lodash/lodash/tree/3.10.0-amd) & [compatibility](https://github.com/lodash/lodash-compat/tree/3.10.0-amd) builds
+ * ES modules for the [modern](https://github.com/lodash/lodash/tree/3.10.0-es) build
 
 ## Further Reading
 
   * [API Documentation](https://lodash.com/docs)
   * [Build Differences](https://github.com/lodash/lodash/wiki/Build-Differences)
   * [Changelog](https://github.com/lodash/lodash/wiki/Changelog)
-  * [Release Notes](https://github.com/lodash/lodash/releases)
   * [Roadmap](https://github.com/lodash/lodash/wiki/Roadmap)
   * [More Resources](https://github.com/lodash/lodash/wiki/Resources)
 
@@ -56,8 +55,7 @@ lodash is also available in a variety of other builds & module formats.
  * ~100% [code coverage](https://coveralls.io/r/lodash)
  * Follows [semantic versioning](http://semver.org/) for releases
  * [Lazily evaluated](http://filimanjaro.com/blog/2014/introducing-lazy-evaluation/) chaining
- * [_(…)](https://lodash.com/docs#_) supports intuitive chaining
- * [_.add](https://lodash.com/docs#add) for mathematical composition
+ * [_(…)](https://lodash.com/docs#_) supports implicit chaining
  * [_.ary](https://lodash.com/docs#ary) & [_.rearg](https://lodash.com/docs#rearg) to change function argument limits & order
  * [_.at](https://lodash.com/docs#at) for cherry-picking collection values
  * [_.attempt](https://lodash.com/docs#attempt) to execute functions which may error without a try-catch
@@ -66,9 +64,9 @@ 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
+ * [_.defaultsDeep](https://lodash.com/docs#defaultsDeep) for recursively assigning default properties
  * [_.fill](https://lodash.com/docs#fill) to fill arrays with values
  * [_.findKey](https://lodash.com/docs#findKey) for finding keys
  * [_.flow](https://lodash.com/docs#flow) to complement [_.flowRight](https://lodash.com/docs#flowRight) (a.k.a `_.compose`)
@@ -76,14 +74,17 @@ lodash is also available in a variety of other builds & module formats.
  * [_.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
+ * [_.gt](https://lodash.com/docs#gt), [_.gte](https://lodash.com/docs#gte), [_.lt](https://lodash.com/docs#lt), & [_.lte](https://lodash.com/docs#lte) relational methods
  * [_.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)
+ * [_.method](https://lodash.com/docs#method) & [_.methodOf](https://lodash.com/docs#methodOf) to create functions that invoke methods
+ * [_.modArgs](https://lodash.com/docs#modArgs) for more advanced functional composition
  * [_.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
  * [_.random](https://lodash.com/docs#random) supports returning floating-point numbers
@@ -91,28 +92,30 @@ lodash is also available in a variety of other builds & module formats.
  * [_.runInContext](https://lodash.com/docs#runInContext) for collisionless mixins & easier mocking
  * [_.slice](https://lodash.com/docs#slice) for creating subsets of array-like values
  * [_.sortByAll](https://lodash.com/docs#sortByAll) & [_.sortByOrder](https://lodash.com/docs#sortByOrder) for sorting by multiple properties & orders
- * [_.sum](https://lodash.com/docs#sum) to get the sum of values
  * [_.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
- * [_.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)
+ * [_.unzipWith](https://lodash.com/docs#unzipWith) & [_.zipWith](https://lodash.com/docs#zipWith) to specify how grouped values should be combined
  * [_.valuesIn](https://lodash.com/docs#valuesIn) for getting values of all enumerable properties
+ * [_.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)
+ * [_.add](https://lodash.com/docs#add), [_.round](https://lodash.com/docs#round), [_.sum](https://lodash.com/docs#sum), &
+   [more](https://lodash.com/docs "_.ceil & _.floor") math methods
  * [_.bind](https://lodash.com/docs#bind), [_.curry](https://lodash.com/docs#curry), [_.partial](https://lodash.com/docs#partial), &
    [more](https://lodash.com/docs "_.bindKey, _.curryRight, _.partialRight") support customizable argument placeholders
  * [_.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 41-42, Firefox 36-37, IE 6-11, Opera 27-28, Safari 5-8, io.js 1.7.1, Node.js 0.8.28, 0.10.38, & 0.12.2, PhantomJS 1.9.8, RingoJS 0.11, & Rhino 1.7RC5.
+Tested in Chrome 42-43, Firefox 37-38, IE 6-11, MS Edge, Opera 28-29, Safari 5-8, ChakraNode 0.12.2, io.js 2.3.1, Node.js 0.8.28, 0.10.38, & 0.12.5, PhantomJS 1.9.8, RingoJS 0.11, & Rhino 1.7.6.
 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/chunk.js

@@ -1,11 +1,10 @@
 var baseSlice = require('../internal/baseSlice'),
     isIterateeCall = require('../internal/isIterateeCall');
 
-/** Native method references. */
-var ceil = Math.ceil;
-
 /* Native method references for those with the same name as other `lodash` methods. */
-var nativeMax = Math.max;
+var nativeCeil = Math.ceil,
+    nativeFloor = Math.floor,
+    nativeMax = Math.max;
 
 /**
  * Creates an array of elements split into groups the length of `size`.
@@ -31,12 +30,12 @@ function chunk(array, size, guard) {
   if (guard ? isIterateeCall(array, size, guard) : size == null) {
     size = 1;
   } else {
-    size = nativeMax(+size || 1, 1);
+    size = nativeMax(nativeFloor(size) || 1, 1);
   }
   var index = 0,
       length = array ? array.length : 0,
       resIndex = -1,
-      result = Array(ceil(length / size));
+      result = Array(nativeCeil(length / size));
 
   while (index < length) {
     result[++resIndex] = baseSlice(array, index, (index += size));

array/difference.js

@@ -1,16 +1,13 @@
 var baseDifference = require('../internal/baseDifference'),
     baseFlatten = require('../internal/baseFlatten'),
-    isArguments = require('../lang/isArguments'),
-    isArray = require('../lang/isArray'),
+    isArrayLike = require('../internal/isArrayLike'),
+    isObjectLike = require('../internal/isObjectLike'),
     restParam = require('../function/restParam');
 
 /**
- * Creates an array excluding all values of the provided arrays using
- * `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`.
+ * Creates an array of unique `array` values not included in the other
+ * provided arrays using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+ * for equality comparisons.
  *
  * @static
  * @memberOf _
@@ -24,7 +21,7 @@ var baseDifference = require('../internal/baseDifference'),
  * // => [1, 3]
  */
 var difference = restParam(function(array, values) {
-  return (isArray(array) || isArguments(array))
+  return (isObjectLike(array) && 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,
- * it is used as the offset 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`.
+ * using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+ * for equality comparisons. If `fromIndex` is negative, it is used as the offset
+ * from the end of `array`. If `array` is sorted providing `true` for `fromIndex`
+ * performs a faster binary search.
  *
  * @static
  * @memberOf _
@@ -43,10 +40,9 @@ function indexOf(array, value, fromIndex) {
   if (typeof fromIndex == 'number') {
     fromIndex = fromIndex < 0 ? nativeMax(length + fromIndex, 0) : fromIndex;
   } else if (fromIndex) {
-    var index = binaryIndex(array, value),
-        other = array[index];
-
-    if (value === value ? (value === other) : (other !== other)) {
+    var index = binaryIndex(array, value);
+    if (index < length &&
+        (value === value ? (value === array[index]) : (array[index] !== array[index]))) {
       return index;
     }
     return -1;

array/intersection.js

@@ -1,17 +1,14 @@
 var baseIndexOf = require('../internal/baseIndexOf'),
     cacheIndexOf = require('../internal/cacheIndexOf'),
     createCache = require('../internal/createCache'),
-    isArguments = require('../lang/isArguments'),
-    isArray = require('../lang/isArray');
+    isArrayLike = require('../internal/isArrayLike'),
+    restParam = require('../function/restParam');
 
 /**
- * Creates an array of unique values in all provided arrays using `SameValueZero`
+ * Creates an array of unique values that are included in all of the provided
+ * arrays using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#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
@@ -21,27 +18,19 @@ var baseIndexOf = require('../internal/baseIndexOf'),
  * _.intersection([1, 2], [4, 2], [2, 1]);
  * // => [2]
  */
-function intersection() {
-  var args = [],
-      argsIndex = -1,
-      argsLength = arguments.length,
-      caches = [],
+var intersection = restParam(function(arrays) {
+  var othLength = arrays.length,
+      othIndex = othLength,
+      caches = Array(length),
       indexOf = baseIndexOf,
       isCommon = true,
       result = [];
 
-  while (++argsIndex < argsLength) {
-    var value = arguments[argsIndex];
-    if (isArray(value) || isArguments(value)) {
-      args.push(value);
-      caches.push((isCommon && value.length >= 120) ? createCache(argsIndex && value) : null);
-    }
+  while (othIndex--) {
+    var value = arrays[othIndex] = isArrayLike(value = arrays[othIndex]) ? value : [];
+    caches[othIndex] = (isCommon && value.length >= 120) ? createCache(othIndex && value) : null;
   }
-  argsLength = args.length;
-  if (argsLength < 2) {
-    return result;
-  }
-  var array = args[0],
+  var array = arrays[0],
       index = -1,
       length = array ? array.length : 0,
       seen = caches[0];
@@ -50,10 +39,10 @@ function intersection() {
   while (++index < length) {
     value = array[index];
     if ((seen ? cacheIndexOf(seen, value) : indexOf(result, value, 0)) < 0) {
-      argsIndex = argsLength;
-      while (--argsIndex) {
-        var cache = caches[argsIndex];
-        if ((cache ? cacheIndexOf(cache, value) : indexOf(args[argsIndex], value, 0)) < 0) {
+      var othIndex = othLength;
+      while (--othIndex) {
+        var cache = caches[othIndex];
+        if ((cache ? cacheIndexOf(cache, value) : indexOf(arrays[othIndex], value, 0)) < 0) {
           continue outer;
         }
       }
@@ -64,6 +53,6 @@ function intersection() {
     }
   }
   return result;
-}
+});
 
 module.exports = intersection;

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
- * comparisons.
+ * Removes all provided values from `array` using
+ * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+ * for equality comparisons.
  *
- * **Notes:**
- *  - 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`
+ * **Note:** Unlike `_.without`, this method mutates `array`.
  *
  * @static
  * @memberOf _

array/pullAt.js

@@ -30,7 +30,6 @@ var baseAt = require('../internal/baseAt'),
  * // => [10, 20]
  */
 var pullAt = restParam(function(array, indexes) {
-  array || (array = []);
   indexes = baseFlatten(indexes);
 
   var result = baseAt(array, indexes);

array/union.js

@@ -3,12 +3,9 @@ var baseFlatten = require('../internal/baseFlatten'),
     restParam = require('../function/restParam');
 
 /**
- * Creates an array of unique values, in order, of the provided arrays using
- * `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`.
+ * Creates an array of unique values, in order, from all of the provided arrays
+ * using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+ * for equality comparisons.
  *
  * @static
  * @memberOf _

array/uniq.js

@@ -4,8 +4,9 @@ var baseCallback = require('../internal/baseCallback'),
     sortedUniq = require('../internal/sortedUniq');
 
 /**
- * Creates a duplicate-free version of an array, using `SameValueZero` for
- * equality comparisons, in which only the first occurence of each element
+ * Creates a duplicate-free version of an array, using
+ * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+ * for equality comparisons, in which only the first occurence of each element
  * is kept. Providing `true` for `isSorted` performs a faster search algorithm
  * for sorted arrays. If an iteratee function is provided it is invoked for
  * each element in the array to generate the criterion by which uniqueness
@@ -23,10 +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
@@ -62,7 +59,7 @@ function uniq(array, isSorted, iteratee, thisArg) {
   }
   if (isSorted != null && typeof isSorted != 'boolean') {
     thisArg = iteratee;
-    iteratee = isIterateeCall(array, isSorted, thisArg) ? null : isSorted;
+    iteratee = isIterateeCall(array, isSorted, thisArg) ? undefined : isSorted;
     isSorted = false;
   }
   iteratee = iteratee == null ? iteratee : baseCallback(iteratee, thisArg, 3);

array/unzip.js

@@ -1,11 +1,14 @@
-var arrayMap = require('../internal/arrayMap'),
-    arrayMax = require('../internal/arrayMax'),
+var arrayFilter = require('../internal/arrayFilter'),
+    arrayMap = require('../internal/arrayMap'),
     baseProperty = require('../internal/baseProperty'),
-    getLength = require('../internal/getLength');
+    isArrayLike = require('../internal/isArrayLike');
+
+/* Native method references for those with the same name as other `lodash` methods. */
+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
@@ -22,10 +25,19 @@ var arrayMap = require('../internal/arrayMap'),
  * // => [['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,
-      result = Array(length);
+      length = 0;
 
+  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'),
-    isArray = require('../lang/isArray'),
+    isArrayLike = require('../internal/isArrayLike'),
     restParam = require('../function/restParam');
 
 /**
- * Creates an array excluding all provided values using `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`.
+ * Creates an array excluding all provided values using
+ * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+ * for equality comparisons.
  *
  * @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

@@ -1,10 +1,10 @@
-var baseDifference = require('../internal/baseDifference'),
+var arrayPush = require('../internal/arrayPush'),
+    baseDifference = require('../internal/baseDifference'),
     baseUniq = require('../internal/baseUniq'),
-    isArguments = require('../lang/isArguments'),
-    isArray = require('../lang/isArray');
+    isArrayLike = require('../internal/isArrayLike');
 
 /**
- * Creates an array that is the [symmetric difference](https://en.wikipedia.org/wiki/Symmetric_difference)
+ * Creates an array of unique values that is the [symmetric difference](https://en.wikipedia.org/wiki/Symmetric_difference)
  * of the provided arrays.
  *
  * @static
@@ -23,9 +23,9 @@ 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))
+        ? arrayPush(baseDifference(result, array), 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 = length > 2 ? arrays[length - 2] : undefined,
+      thisArg = length > 1 ? arrays[length - 1] : undefined;
+
+  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.js

@@ -1,6 +1,7 @@
 module.exports = {
   'chain': require('./chain/chain'),
   'commit': require('./chain/commit'),
+  'concat': require('./chain/concat'),
   'lodash': require('./chain/lodash'),
   'plant': require('./chain/plant'),
   'reverse': require('./chain/reverse'),

chain/concat.js

@@ -0,0 +1 @@
+module.exports = require('./wrapperConcat');

chain/lodash.js

@@ -14,15 +14,16 @@ var hasOwnProperty = objectProto.hasOwnProperty;
 /**
  * Creates a `lodash` object which wraps `value` to enable implicit chaining.
  * Methods that operate on and return arrays, collections, and functions can
- * be chained together. Methods that return a boolean or single value will
- * automatically end the chain returning the unwrapped value. Explicit chaining
- * may be enabled using `_.chain`. The execution of chained methods is lazy,
- * that is, execution is deferred until `_#value` is implicitly or explicitly
- * called.
+ * be chained together. Methods that retrieve a single value or may return a
+ * primitive value will automatically end the chain returning the unwrapped
+ * value. Explicit chaining may be enabled using `_.chain`. The execution of
+ * chained methods is lazy, that is, execution is deferred until `_#value`
+ * is implicitly or explicitly called.
  *
  * Lazy evaluation allows several methods to support shortcut fusion. Shortcut
- * fusion is an optimization that merges iteratees to avoid creating intermediate
- * arrays and reduce the number of iteratee executions.
+ * fusion is an optimization strategy which merge iteratee calls; this can help
+ * to avoid the creation of intermediate data structures and greatly reduce the
+ * number of iteratee executions.
  *
  * Chaining is supported in custom builds as long as the `_#value` method is
  * directly or indirectly included in the build.
@@ -45,35 +46,37 @@ var hasOwnProperty = objectProto.hasOwnProperty;
  * The chainable wrapper methods are:
  * `after`, `ary`, `assign`, `at`, `before`, `bind`, `bindAll`, `bindKey`,
  * `callback`, `chain`, `chunk`, `commit`, `compact`, `concat`, `constant`,
- * `countBy`, `create`, `curry`, `debounce`, `defaults`, `defer`, `delay`,
- * `difference`, `drop`, `dropRight`, `dropRightWhile`, `dropWhile`, `fill`,
- * `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`, `mixin`, `negate`, `omit`, `once`, `pairs`, `partial`, `partialRight`,
+ * `countBy`, `create`, `curry`, `debounce`, `defaults`, `defaultsDeep`,
+ * `defer`, `delay`, `difference`, `drop`, `dropRight`, `dropRightWhile`,
+ * `dropWhile`, `fill`, `filter`, `flatten`, `flattenDeep`, `flow`, `flowRight`,
+ * `forEach`, `forEachRight`, `forIn`, `forInRight`, `forOwn`, `forOwnRight`,
+ * `functions`, `groupBy`, `indexBy`, `initial`, `intersection`, `invert`,
+ * `invoke`, `keys`, `keysIn`, `map`, `mapKeys`, `mapValues`, `matches`,
+ * `matchesProperty`, `memoize`, `merge`, `method`, `methodOf`, `mixin`,
+ * `modArgs`, `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`,
- * `spread`, `take`, `takeRight`, `takeRightWhile`, `takeWhile`, `tap`,
- * `throttle`, `thru`, `times`, `toArray`, `toPlainObject`, `transform`,
- * `union`, `uniq`, `unshift`, `unzip`, `values`, `valuesIn`, `where`,
- * `without`, `wrap`, `xor`, `zip`, and `zipObject`
+ * `pullAt`, `push`, `range`, `rearg`, `reject`, `remove`, `rest`, `restParam`,
+ * `reverse`, `set`, `shuffle`, `slice`, `sort`, `sortBy`, `sortByAll`,
+ * `sortByOrder`, `splice`, `spread`, `take`, `takeRight`, `takeRightWhile`,
+ * `takeWhile`, `tap`, `throttle`, `thru`, `times`, `toArray`, `toPlainObject`,
+ * `transform`, `union`, `uniq`, `unshift`, `unzip`, `unzipWith`, `values`,
+ * `valuesIn`, `where`, `without`, `wrap`, `xor`, `zip`, `zipObject`, `zipWith`
  *
  * The wrapper methods that are **not** chainable by default are:
- * `add`, `attempt`, `camelCase`, `capitalize`, `clone`, `cloneDeep`, `deburr`,
- * `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`, `isFinite`
- * `isFunction`, `isMatch`, `isNative`, `isNaN`, `isNull`, `isNumber`, `isObject`,
- * `isPlainObject`, `isRegExp`, `isString`, `isUndefined`, `isTypedArray`,
- * `join`, `kebabCase`, `last`, `lastIndexOf`, `max`, `min`, `noConflict`,
- * `noop`, `now`, `pad`, `padLeft`, `padRight`, `parseInt`, `pop`, `random`,
- * `reduce`, `reduceRight`, `repeat`, `result`, `runInContext`, `shift`, `size`,
- * `snakeCase`, `some`, `sortedIndex`, `sortedLastIndex`, `startCase`, `startsWith`,
- * `sum`, `template`, `trim`, `trimLeft`, `trimRight`, `trunc`, `unescape`,
- * `uniqueId`, `value`, and `words`
+ * `add`, `attempt`, `camelCase`, `capitalize`, `ceil`, `clone`, `cloneDeep`,
+ * `deburr`, `endsWith`, `escape`, `escapeRegExp`, `every`, `find`, `findIndex`,
+ * `findKey`, `findLast`, `findLastIndex`, `findLastKey`, `findWhere`, `first`,
+ * `floor`, `get`, `gt`, `gte`, `has`, `identity`, `includes`, `indexOf`,
+ * `inRange`, `isArguments`, `isArray`, `isBoolean`, `isDate`, `isElement`,
+ * `isEmpty`, `isEqual`, `isError`, `isFinite` `isFunction`, `isMatch`,
+ * `isNative`, `isNaN`, `isNull`, `isNumber`, `isObject`, `isPlainObject`,
+ * `isRegExp`, `isString`, `isUndefined`, `isTypedArray`, `join`, `kebabCase`,
+ * `last`, `lastIndexOf`, `lt`, `lte`, `max`, `min`, `noConflict`, `noop`,
+ * `now`, `pad`, `padLeft`, `padRight`, `parseInt`, `pop`, `random`, `reduce`,
+ * `reduceRight`, `repeat`, `result`, `round`, `runInContext`, `shift`, `size`,
+ * `snakeCase`, `some`, `sortedIndex`, `sortedLastIndex`, `startCase`,
+ * `startsWith`, `sum`, `template`, `trim`, `trimLeft`, `trimRight`, `trunc`,
+ * `unescape`, `uniqueId`, `value`, and `words`
  *
  * The wrapper method `sample` will return a wrapped value when `n` is provided,
  * otherwise an unwrapped value is returned.

chain/wrapperCommit.js

@@ -10,16 +10,16 @@ var LodashWrapper = require('../internal/LodashWrapper');
  * @example
  *
  * var array = [1, 2];
- * var wrapper = _(array).push(3);
+ * var wrapped = _(array).push(3);
  *
  * console.log(array);
  * // => [1, 2]
  *
- * wrapper = wrapper.commit();
+ * wrapped = wrapped.commit();
  * console.log(array);
  * // => [1, 2, 3]
  *
- * wrapper.last();
+ * wrapped.last();
  * // => 3
  *
  * console.log(array);

chain/wrapperConcat.js

@@ -0,0 +1,34 @@
+var arrayConcat = require('../internal/arrayConcat'),
+    baseFlatten = require('../internal/baseFlatten'),
+    isArray = require('../lang/isArray'),
+    restParam = require('../function/restParam'),
+    toObject = require('../internal/toObject');
+
+/**
+ * Creates a new array joining a wrapped array with any additional arrays
+ * and/or values.
+ *
+ * @name concat
+ * @memberOf _
+ * @category Chain
+ * @param {...*} [values] The values to concatenate.
+ * @returns {Array} Returns the new concatenated array.
+ * @example
+ *
+ * var array = [1];
+ * var wrapped = _(array).concat(2, [3], [[4]]);
+ *
+ * console.log(wrapped.value());
+ * // => [1, 2, 3, [4]]
+ *
+ * console.log(array);
+ * // => [1]
+ */
+var wrapperConcat = restParam(function(values) {
+  values = baseFlatten(values);
+  return this.thru(function(array) {
+    return arrayConcat(isArray(array) ? array : [toObject(array)], values);
+  });
+});
+
+module.exports = wrapperConcat;

chain/wrapperPlant.js

@@ -11,17 +11,17 @@ var baseLodash = require('../internal/baseLodash'),
  * @example
  *
  * var array = [1, 2];
- * var wrapper = _(array).map(function(value) {
+ * var wrapped = _(array).map(function(value) {
  *   return Math.pow(value, 2);
  * });
  *
  * var other = [3, 4];
- * var otherWrapper = wrapper.plant(other);
+ * var otherWrapped = wrapped.plant(other);
  *
- * otherWrapper.value();
+ * otherWrapped.value();
  * // => [9, 16]
  *
- * wrapper.value();
+ * wrapped.value();
  * // => [1, 4]
  */
 function wrapperPlant(value) {

chain/wrapperReverse.js

@@ -24,15 +24,20 @@ var LazyWrapper = require('../internal/LazyWrapper'),
  */
 function wrapperReverse() {
   var value = this.__wrapped__;
+
+  var interceptor = function(value) {
+    return (wrapped && wrapped.__dir__ < 0) ? value : value.reverse();
+  };
   if (value instanceof LazyWrapper) {
+    var wrapped = value;
     if (this.__actions__.length) {
-      value = new LazyWrapper(this);
+      wrapped = new LazyWrapper(this);
     }
-    return new LodashWrapper(value.reverse(), this.__chain__);
+    wrapped = wrapped.reverse();
+    wrapped.__actions__.push({ 'func': thru, 'args': [interceptor], 'thisArg': undefined });
+    return new LodashWrapper(wrapped, this.__chain__);
   }
-  return this.thru(function(value) {
-    return value.reverse();
-  });
+  return this.thru(interceptor);
 }
 
 module.exports = wrapperReverse;

collection/at.js

@@ -1,9 +1,6 @@
 var baseAt = require('../internal/baseAt'),
     baseFlatten = require('../internal/baseFlatten'),
-    getLength = require('../internal/getLength'),
-    isLength = require('../internal/isLength'),
-    restParam = require('../function/restParam'),
-    toIterable = require('../internal/toIterable');
+    restParam = require('../function/restParam');
 
 /**
  * Creates an array of elements corresponding to the given keys, or indexes,
@@ -26,10 +23,6 @@ var baseAt = require('../internal/baseAt'),
  * // => ['barney', 'pebbles']
  */
 var at = restParam(function(collection, props) {
-  var length = collection ? getLength(collection) : 0;
-  if (isLength(length)) {
-    collection = toIterable(collection);
-  }
   return baseAt(collection, baseFlatten(props));
 });
 

collection/every.js

@@ -55,7 +55,7 @@ var arrayEvery = require('../internal/arrayEvery'),
 function every(collection, predicate, thisArg) {
   var func = isArray(collection) ? arrayEvery : baseEvery;
   if (thisArg && isIterateeCall(collection, predicate, thisArg)) {
-    predicate = null;
+    predicate = undefined;
   }
   if (typeof predicate != 'function' || thisArg !== undefined) {
     predicate = baseCallback(predicate, thisArg, 3);

collection/includes.js

@@ -10,13 +10,10 @@ var baseIndexOf = require('../internal/baseIndexOf'),
 var nativeMax = Math.max;
 
 /**
- * Checks if `value` is in `collection` using `SameValueZero` 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`.
+ * Checks if `value` is in `collection` using
+ * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+ * for equality comparisons. If `fromIndex` is negative, it is used as the offset
+ * from the end of `collection`.
  *
  * @static
  * @memberOf _
@@ -47,17 +44,14 @@ function includes(collection, target, fromIndex, guard) {
     collection = values(collection);
     length = collection.length;
   }
-  if (!length) {
-    return false;
-  }
   if (typeof fromIndex != 'number' || (guard && isIterateeCall(target, fromIndex, guard))) {
     fromIndex = 0;
   } else {
     fromIndex = fromIndex < 0 ? nativeMax(length + fromIndex, 0) : (fromIndex || 0);
   }
   return (typeof collection == 'string' || !isArray(collection) && isString(collection))
-    ? (fromIndex < length && collection.indexOf(target, fromIndex) > -1)
-    : (baseIndexOf(collection, target, fromIndex) > -1);
+    ? (fromIndex <= length && collection.indexOf(target, fromIndex) > -1)
+    : (!!length && baseIndexOf(collection, target, fromIndex) > -1);
 }
 
 module.exports = includes;

collection/invoke.js

@@ -1,12 +1,11 @@
 var baseEach = require('../internal/baseEach'),
-    getLength = require('../internal/getLength'),
     invokePath = require('../internal/invokePath'),
+    isArrayLike = require('../internal/isArrayLike'),
     isKey = require('../internal/isKey'),
-    isLength = require('../internal/isLength'),
     restParam = require('../function/restParam');
 
 /**
- * Invokes the method at `path` on each element in `collection`, returning
+ * Invokes the method at `path` of each element in `collection`, returning
  * an array of the results of each invoked method. Any additional arguments
  * are provided to each invoked method. If `methodName` is a function it is
  * invoked for, and `this` bound to, each element in `collection`.
@@ -31,11 +30,10 @@ var invoke = restParam(function(collection, path, args) {
   var index = -1,
       isFunc = typeof path == 'function',
       isProp = isKey(path),
-      length = getLength(collection),
-      result = isLength(length) ? Array(length) : [];
+      result = isArrayLike(collection) ? Array(collection.length) : [];
 
   baseEach(collection, function(value) {
-    var func = isFunc ? path : (isProp && value != null && value[path]);
+    var func = isFunc ? path : ((isProp && value != null) ? value[path] : undefined);
     result[++index] = func ? func.apply(value, args) : invokePath(value, path, args);
   });
   return result;

collection/map.js

@@ -19,14 +19,15 @@ var arrayMap = require('../internal/arrayMap'),
  * callback returns `true` for elements that have the properties of the given
  * object, else `false`.
  *
- * Many lodash methods are guarded to work as interatees for methods like
+ * Many lodash methods are guarded to work as iteratees for methods like
  * `_.every`, `_.filter`, `_.map`, `_.mapValues`, `_.reject`, and `_.some`.
  *
  * The guarded methods are:
- * `ary`, `callback`, `chunk`, `clone`, `create`, `curry`, `curryRight`, `drop`,
- * `dropRight`, `every`, `fill`, `flatten`, `invert`, `max`, `min`, `parseInt`,
- * `slice`, `sortBy`, `take`, `takeRight`, `template`, `trim`, `trimLeft`,
- * `trimRight`, `trunc`, `random`, `range`, `sample`, `some`, `uniq`, and `words`
+ * `ary`, `callback`, `chunk`, `clone`, `create`, `curry`, `curryRight`,
+ * `drop`, `dropRight`, `every`, `fill`, `flatten`, `invert`, `max`, `min`,
+ * `parseInt`, `slice`, `sortBy`, `take`, `takeRight`, `template`, `trim`,
+ * `trimLeft`, `trimRight`, `trunc`, `random`, `range`, `sample`, `some`,
+ * `sum`, `uniq`, and `words`
  *
  * @static
  * @memberOf _

collection/reduce.js

@@ -10,11 +10,12 @@ var arrayReduce = require('../internal/arrayReduce'),
  * value. The `iteratee` is bound to `thisArg` and invoked with four arguments:
  * (accumulator, value, index|key, collection).
  *
- * Many lodash methods are guarded to work as interatees for methods like
+ * Many lodash methods are guarded to work as iteratees for methods like
  * `_.reduce`, `_.reduceRight`, and `_.transform`.
  *
  * The guarded methods are:
- * `assign`, `defaults`, `includes`, `merge`, `sortByAll`, and `sortByOrder`
+ * `assign`, `defaults`, `defaultsDeep`, `includes`, `merge`, `sortByAll`,
+ * and `sortByOrder`
  *
  * @static
  * @memberOf _

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/sample.js

@@ -1,6 +1,6 @@
 var baseRandom = require('../internal/baseRandom'),
     isIterateeCall = require('../internal/isIterateeCall'),
-    shuffle = require('./shuffle'),
+    toArray = require('../lang/toArray'),
     toIterable = require('../internal/toIterable');
 
 /* Native method references for those with the same name as other `lodash` methods. */
@@ -30,8 +30,20 @@ function sample(collection, n, guard) {
     var length = collection.length;
     return length > 0 ? collection[baseRandom(0, length - 1)] : undefined;
   }
-  var result = shuffle(collection);
-  result.length = nativeMin(n < 0 ? 0 : (+n || 0), result.length);
+  var index = -1,
+      result = toArray(collection),
+      length = result.length,
+      lastIndex = length - 1;
+
+  n = nativeMin(n < 0 ? 0 : (+n || 0), length);
+  while (++index < n) {
+    var rand = baseRandom(index, lastIndex),
+        value = result[rand];
+
+    result[rand] = result[index];
+    result[index] = value;
+  }
+  result.length = n;
   return result;
 }
 

collection/shuffle.js

@@ -1,5 +1,7 @@
-var baseRandom = require('../internal/baseRandom'),
-    toIterable = require('../internal/toIterable');
+var sample = require('./sample');
+
+/** Used as references for `-Infinity` and `Infinity`. */
+var POSITIVE_INFINITY = Number.POSITIVE_INFINITY;
 
 /**
  * Creates an array of shuffled values, using a version of the
@@ -16,20 +18,7 @@ var baseRandom = require('../internal/baseRandom'),
  * // => [4, 1, 3, 2]
  */
 function shuffle(collection) {
-  collection = toIterable(collection);
-
-  var index = -1,
-      length = collection.length,
-      result = Array(length);
-
-  while (++index < length) {
-    var rand = baseRandom(0, index);
-    if (index != rand) {
-      result[index] = result[rand];
-    }
-    result[rand] = collection[index];
-  }
-  return result;
+  return sample(collection, POSITIVE_INFINITY);
 }
 
 module.exports = shuffle;

collection/some.js

@@ -56,7 +56,7 @@ var arraySome = require('../internal/arraySome'),
 function some(collection, predicate, thisArg) {
   var func = isArray(collection) ? arraySome : baseSome;
   if (thisArg && isIterateeCall(collection, predicate, thisArg)) {
-    predicate = null;
+    predicate = undefined;
   }
   if (typeof predicate != 'function' || thisArg !== undefined) {
     predicate = baseCallback(predicate, thisArg, 3);

collection/sortBy.js

@@ -57,7 +57,7 @@ function sortBy(collection, iteratee, thisArg) {
     return [];
   }
   if (thisArg && isIterateeCall(collection, iteratee, thisArg)) {
-    iteratee = null;
+    iteratee = undefined;
   }
   var index = -1;
   iteratee = baseCallback(iteratee, thisArg, 3);

collection/sortByOrder.js

@@ -4,9 +4,9 @@ var baseSortByOrder = require('../internal/baseSortByOrder'),
 
 /**
  * This method is like `_.sortByAll` except that it allows specifying the
- * sort orders of the iteratees to sort by. A truthy value in `orders` will
- * sort the corresponding property name in ascending order while a falsey
- * value will sort it in descending order.
+ * sort orders of the iteratees to sort by. If `orders` is unspecified, all
+ * values are sorted in ascending order. Otherwise, a value is sorted in
+ * ascending order if its corresponding order is "asc", and descending if "desc".
  *
  * If a property name is provided for an iteratee the created `_.property`
  * style callback returns the property value of the given element.
@@ -20,7 +20,7 @@ var baseSortByOrder = require('../internal/baseSortByOrder'),
  * @category Collection
  * @param {Array|Object|string} collection The collection to iterate over.
  * @param {Function[]|Object[]|string[]} iteratees The iteratees to sort by.
- * @param {boolean[]} orders The sort orders of `iteratees`.
+ * @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
@@ -33,7 +33,7 @@ var baseSortByOrder = require('../internal/baseSortByOrder'),
  * ];
  *
  * // sort by `user` in ascending order and by `age` in descending order
- * _.map(_.sortByOrder(users, ['user', 'age'], [true, false]), _.values);
+ * _.map(_.sortByOrder(users, ['user', 'age'], ['asc', 'desc']), _.values);
  * // => [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 42]]
  */
 function sortByOrder(collection, iteratees, orders, guard) {
@@ -41,7 +41,7 @@ function sortByOrder(collection, iteratees, orders, guard) {
     return [];
   }
   if (guard && isIterateeCall(iteratees, orders, guard)) {
-    orders = null;
+    orders = undefined;
   }
   if (!isArray(iteratees)) {
     iteratees = iteratees == null ? [] : [iteratees];

date/now.js

@@ -1,7 +1,7 @@
-var isNative = require('../lang/isNative');
+var getNative = require('../internal/getNative');
 
 /* Native method references for those with the same name as other `lodash` methods. */
-var nativeNow = isNative(nativeNow = Date.now) && nativeNow;
+var nativeNow = getNative(Date, 'now');
 
 /**
  * Gets the number of milliseconds that have elapsed since the Unix epoch

function.js

@@ -15,6 +15,7 @@ module.exports = {
   'flow': require('./function/flow'),
   'flowRight': require('./function/flowRight'),
   'memoize': require('./function/memoize'),
+  'modArgs': require('./function/modArgs'),
   'negate': require('./function/negate'),
   'once': require('./function/once'),
   'partial': require('./function/partial'),

function/ary.js

@@ -25,10 +25,10 @@ var nativeMax = Math.max;
  */
 function ary(func, n, guard) {
   if (guard && isIterateeCall(func, n, guard)) {
-    n = null;
+    n = undefined;
   }
   n = (func && n == null) ? func.length : nativeMax(+n || 0, 0);
-  return createWrapper(func, ARY_FLAG, null, null, null, null, n);
+  return createWrapper(func, ARY_FLAG, undefined, undefined, undefined, undefined, n);
 }
 
 module.exports = ary;

function/before.js

@@ -33,7 +33,7 @@ function before(n, func) {
       result = func.apply(this, arguments);
     }
     if (n <= 1) {
-      func = null;
+      func = undefined;
     }
     return result;
   };

function/debounce.js

@@ -8,12 +8,13 @@ var FUNC_ERROR_TEXT = 'Expected a function';
 var nativeMax = Math.max;
 
 /**
- * Creates a function that delays invoking `func` until after `wait` milliseconds
- * have elapsed since the last time it was invoked. The created function comes
- * with a `cancel` method to cancel delayed invocations. Provide an options
- * object to indicate that `func` should be invoked on the leading and/or
- * trailing edge of the `wait` timeout. Subsequent calls to the debounced
- * function return the result of the last `func` invocation.
+ * Creates a debounced function that delays invoking `func` until after `wait`
+ * milliseconds have elapsed since the last time the debounced function was
+ * invoked. The debounced function comes with a `cancel` method to cancel
+ * delayed invocations. Provide an options object to indicate that `func`
+ * should be invoked on the leading and/or trailing edge of the `wait` timeout.
+ * Subsequent calls to the debounced function return the result of the last
+ * `func` invocation.
  *
  * **Note:** If `leading` and `trailing` options are `true`, `func` is invoked
  * on the trailing edge of the timeout only if the the debounced function is
@@ -89,9 +90,9 @@ function debounce(func, wait, options) {
     var leading = true;
     trailing = false;
   } else if (isObject(options)) {
-    leading = options.leading;
+    leading = !!options.leading;
     maxWait = 'maxWait' in options && nativeMax(+options.maxWait || 0, wait);
-    trailing = 'trailing' in options ? options.trailing : trailing;
+    trailing = 'trailing' in options ? !!options.trailing : trailing;
   }
 
   function cancel() {
@@ -101,41 +102,35 @@ function debounce(func, wait, options) {
     if (maxTimeoutId) {
       clearTimeout(maxTimeoutId);
     }
+    lastCalled = 0;
     maxTimeoutId = timeoutId = trailingCall = undefined;
   }
 
+  function complete(isCalled, id) {
+    if (id) {
+      clearTimeout(id);
+    }
+    maxTimeoutId = timeoutId = trailingCall = undefined;
+    if (isCalled) {
+      lastCalled = now();
+      result = func.apply(thisArg, args);
+      if (!timeoutId && !maxTimeoutId) {
+        args = thisArg = undefined;
+      }
+    }
+  }
+
   function delayed() {
     var remaining = wait - (now() - stamp);
     if (remaining <= 0 || remaining > wait) {
-      if (maxTimeoutId) {
-        clearTimeout(maxTimeoutId);
-      }
-      var isCalled = trailingCall;
-      maxTimeoutId = timeoutId = trailingCall = undefined;
-      if (isCalled) {
-        lastCalled = now();
-        result = func.apply(thisArg, args);
-        if (!timeoutId && !maxTimeoutId) {
-          args = thisArg = null;
-        }
-      }
+      complete(trailingCall, maxTimeoutId);
     } else {
       timeoutId = setTimeout(delayed, remaining);
     }
   }
 
   function maxDelayed() {
-    if (timeoutId) {
-      clearTimeout(timeoutId);
-    }
-    maxTimeoutId = timeoutId = trailingCall = undefined;
-    if (trailing || (maxWait !== wait)) {
-      lastCalled = now();
-      result = func.apply(thisArg, args);
-      if (!timeoutId && !maxTimeoutId) {
-        args = thisArg = null;
-      }
-    }
+    complete(trailing, timeoutId);
   }
 
   function debounced() {
@@ -175,7 +170,7 @@ function debounce(func, wait, options) {
       result = func.apply(thisArg, args);
     }
     if (isCalled && !timeoutId && !maxTimeoutId) {
-      args = thisArg = null;
+      args = thisArg = undefined;
     }
     return result;
   }

function/memoize.js

@@ -13,7 +13,7 @@ var FUNC_ERROR_TEXT = 'Expected a function';
  *
  * **Note:** The cache is exposed as the `cache` property on the memoized
  * function. Its creation may be customized by replacing the `_.memoize.Cache`
- * constructor with one whose instances implement the [`Map`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-properties-of-the-map-prototype-object)
+ * constructor with one whose instances implement the [`Map`](http://ecma-international.org/ecma-262/6.0/#sec-properties-of-the-map-prototype-object)
  * method interface of `get`, `has`, and `set`.
  *
  * @static
@@ -60,14 +60,14 @@ function memoize(func, resolver) {
   }
   var memoized = function() {
     var args = arguments,
-        cache = memoized.cache,
-        key = resolver ? resolver.apply(this, args) : args[0];
+        key = resolver ? resolver.apply(this, args) : args[0],
+        cache = memoized.cache;
 
     if (cache.has(key)) {
       return cache.get(key);
     }
     var result = func.apply(this, args);
-    cache.set(key, result);
+    memoized.cache = cache.set(key, result);
     return result;
   };
   memoized.cache = new memoize.Cache;

function/modArgs.js

@@ -0,0 +1,58 @@
+var arrayEvery = require('../internal/arrayEvery'),
+    baseFlatten = require('../internal/baseFlatten'),
+    baseIsFunction = require('../internal/baseIsFunction'),
+    restParam = require('./restParam');
+
+/** Used as the `TypeError` message for "Functions" methods. */
+var FUNC_ERROR_TEXT = 'Expected a function';
+
+/* Native method references for those with the same name as other `lodash` methods. */
+var nativeMin = Math.min;
+
+/**
+ * Creates a function that runs each argument through a corresponding
+ * transform function.
+ *
+ * @static
+ * @memberOf _
+ * @category Function
+ * @param {Function} func The function to wrap.
+ * @param {...(Function|Function[])} [transforms] The functions to transform
+ * arguments, specified as individual functions or arrays of functions.
+ * @returns {Function} Returns the new function.
+ * @example
+ *
+ * function doubled(n) {
+ *   return n * 2;
+ * }
+ *
+ * function square(n) {
+ *   return n * n;
+ * }
+ *
+ * var modded = _.modArgs(function(x, y) {
+ *   return [x, y];
+ * }, square, doubled);
+ *
+ * modded(1, 2);
+ * // => [1, 4]
+ *
+ * modded(5, 10);
+ * // => [25, 20]
+ */
+var modArgs = restParam(function(func, transforms) {
+  transforms = baseFlatten(transforms);
+  if (typeof func != 'function' || !arrayEvery(transforms, baseIsFunction)) {
+    throw new TypeError(FUNC_ERROR_TEXT);
+  }
+  var length = transforms.length;
+  return restParam(function(args) {
+    var index = nativeMin(args.length, length);
+    while (index--) {
+      args[index] = transforms[index](args[index]);
+    }
+    return func.apply(this, args);
+  });
+});
+
+module.exports = modArgs;

function/rearg.js

@@ -34,7 +34,7 @@ var REARG_FLAG = 256;
  * // => [3, 6, 9]
  */
 var rearg = restParam(function(func, indexes) {
-  return createWrapper(func, REARG_FLAG, null, null, null, baseFlatten(indexes));
+  return createWrapper(func, REARG_FLAG, undefined, undefined, undefined, baseFlatten(indexes));
 });
 
 module.exports = rearg;

function/throttle.js

@@ -4,20 +4,13 @@ var debounce = require('./debounce'),
 /** Used as the `TypeError` message for "Functions" methods. */
 var FUNC_ERROR_TEXT = 'Expected a function';
 
-/** Used as an internal `_.debounce` options object by `_.throttle`. */
-var debounceOptions = {
-  'leading': false,
-  'maxWait': 0,
-  'trailing': false
-};
-
 /**
- * Creates a function that only invokes `func` at most once per every `wait`
- * milliseconds. The created function comes with a `cancel` method to cancel
- * delayed invocations. Provide an options object to indicate that `func`
- * should be invoked on the leading and/or trailing edge of the `wait` timeout.
- * Subsequent calls to the throttled function return the result of the last
- * `func` call.
+ * Creates a throttled function that only invokes `func` at most once per
+ * every `wait` milliseconds. The throttled function comes with a `cancel`
+ * method to cancel delayed invocations. Provide an options object to indicate
+ * that `func` should be invoked on the leading and/or trailing edge of the
+ * `wait` timeout. Subsequent calls to the throttled function return the
+ * result of the last `func` call.
  *
  * **Note:** If `leading` and `trailing` options are `true`, `func` is invoked
  * on the trailing edge of the timeout only if the the throttled function is
@@ -63,10 +56,7 @@ function throttle(func, wait, options) {
     leading = 'leading' in options ? !!options.leading : leading;
     trailing = 'trailing' in options ? !!options.trailing : trailing;
   }
-  debounceOptions.leading = leading;
-  debounceOptions.maxWait = +wait;
-  debounceOptions.trailing = trailing;
-  return debounce(func, wait, debounceOptions);
+  return debounce(func, wait, { 'leading': leading, 'maxWait': +wait, 'trailing': trailing });
 }
 
 module.exports = throttle;

function/wrap.js

@@ -27,7 +27,7 @@ var PARTIAL_FLAG = 32;
  */
 function wrap(value, wrapper) {
   wrapper = wrapper == null ? identity : wrapper;
-  return createWrapper(wrapper, PARTIAL_FLAG, null, [value], []);
+  return createWrapper(wrapper, PARTIAL_FLAG, undefined, [value], []);
 }
 
 module.exports = wrap;

internal/LazyWrapper.js

@@ -12,13 +12,12 @@ var POSITIVE_INFINITY = Number.POSITIVE_INFINITY;
  */
 function LazyWrapper(value) {
   this.__wrapped__ = value;
-  this.__actions__ = null;
+  this.__actions__ = [];
   this.__dir__ = 1;
-  this.__dropCount__ = 0;
   this.__filtered__ = false;
-  this.__iteratees__ = null;
+  this.__iteratees__ = [];
   this.__takeCount__ = POSITIVE_INFINITY;
-  this.__views__ = null;
+  this.__views__ = [];
 }
 
 LazyWrapper.prototype = baseCreate(baseLodash.prototype);

internal/SetCache.js

@@ -1,11 +1,11 @@
 var cachePush = require('./cachePush'),
-    isNative = require('../lang/isNative');
+    getNative = require('./getNative');
 
 /** Native method references. */
-var Set = isNative(Set = global.Set) && Set;
+var Set = getNative(global, 'Set');
 
 /* Native method references for those with the same name as other `lodash` methods. */
-var nativeCreate = isNative(nativeCreate = Object.create) && nativeCreate;
+var nativeCreate = getNative(Object, 'create');
 
 /**
  *

internal/arrayConcat.js

@@ -0,0 +1,25 @@
+/**
+ * Creates a new array joining `array` with `other`.
+ *
+ * @private
+ * @param {Array} array The array to join.
+ * @param {Array} other The other array to join.
+ * @returns {Array} Returns the new concatenated array.
+ */
+function arrayConcat(array, other) {
+  var index = -1,
+      length = array.length,
+      othIndex = -1,
+      othLength = other.length,
+      result = Array(length + othLength);
+
+  while (++index < length) {
+    result[index] = array[index];
+  }
+  while (++othIndex < othLength) {
+    result[index++] = other[othIndex];
+  }
+  return result;
+}
+
+module.exports = arrayConcat;

internal/arrayExtremum.js

@@ -0,0 +1,30 @@
+/**
+ * A specialized version of `baseExtremum` for arrays which invokes `iteratee`
+ * with one argument: (value).
+ *
+ * @private
+ * @param {Array} array The array to iterate over.
+ * @param {Function} iteratee The function invoked per iteration.
+ * @param {Function} comparator The function used to compare values.
+ * @param {*} exValue The initial extremum value.
+ * @returns {*} Returns the extremum value.
+ */
+function arrayExtremum(array, iteratee, comparator, exValue) {
+  var index = -1,
+      length = array.length,
+      computed = exValue,
+      result = computed;
+
+  while (++index < length) {
+    var value = array[index],
+        current = +iteratee(value);
+
+    if (comparator(current, computed)) {
+      computed = current;
+      result = value;
+    }
+  }
+  return result;
+}
+
+module.exports = arrayExtremum;

internal/arrayMax.js

@@ -1,25 +0,0 @@
-/** Used as references for `-Infinity` and `Infinity`. */
-var NEGATIVE_INFINITY = Number.NEGATIVE_INFINITY;
-
-/**
- * A specialized version of `_.max` for arrays without support for iteratees.
- *
- * @private
- * @param {Array} array The array to iterate over.
- * @returns {*} Returns the maximum value.
- */
-function arrayMax(array) {
-  var index = -1,
-      length = array.length,
-      result = NEGATIVE_INFINITY;
-
-  while (++index < length) {
-    var value = array[index];
-    if (value > result) {
-      result = value;
-    }
-  }
-  return result;
-}
-
-module.exports = arrayMax;

internal/arrayMin.js

@@ -1,25 +0,0 @@
-/** Used as references for `-Infinity` and `Infinity`. */
-var POSITIVE_INFINITY = Number.POSITIVE_INFINITY;
-
-/**
- * A specialized version of `_.min` for arrays without support for iteratees.
- *
- * @private
- * @param {Array} array The array to iterate over.
- * @returns {*} Returns the minimum value.
- */
-function arrayMin(array) {
-  var index = -1,
-      length = array.length,
-      result = POSITIVE_INFINITY;
-
-  while (++index < length) {
-    var value = array[index];
-    if (value < result) {
-      result = value;
-    }
-  }
-  return result;
-}
-
-module.exports = arrayMin;

internal/arrayPush.js

@@ -0,0 +1,20 @@
+/**
+ * Appends the elements of `values` to `array`.
+ *
+ * @private
+ * @param {Array} array The array to modify.
+ * @param {Array} values The values to append.
+ * @returns {Array} Returns `array`.
+ */
+function arrayPush(array, values) {
+  var index = -1,
+      length = values.length,
+      offset = array.length;
+
+  while (++index < length) {
+    array[offset + index] = values[index];
+  }
+  return array;
+}
+
+module.exports = arrayPush;

internal/arraySum.js

@@ -1,16 +1,18 @@
 /**
- * A specialized version of `_.sum` for arrays without support for iteratees.
+ * A specialized version of `_.sum` for arrays without support for callback
+ * shorthands and `this` binding..
  *
  * @private
  * @param {Array} array The array to iterate over.
+ * @param {Function} iteratee The function invoked per iteration.
  * @returns {number} Returns the sum.
  */
-function arraySum(array) {
+function arraySum(array, iteratee) {
   var length = array.length,
       result = 0;
 
   while (length--) {
-    result += +array[length] || 0;
+    result += +iteratee(array[length]) || 0;
   }
   return result;
 }

internal/assignWith.js

@@ -1,11 +1,4 @@
-var getSymbols = require('./getSymbols'),
-    keys = require('../object/keys');
-
-/** Used for native method references. */
-var arrayProto = Array.prototype;
-
-/** Native method references. */
-var push = arrayProto.push;
+var keys = require('../object/keys');
 
 /**
  * A specialized version of `_.assign` for customizing assigned values without
@@ -19,10 +12,8 @@ var push = arrayProto.push;
  * @returns {Object} Returns `object`.
  */
 function assignWith(object, source, customizer) {
-  var props = keys(source);
-  push.apply(props, getSymbols(source));
-
   var index = -1,
+      props = keys(source),
       length = props.length;
 
   while (++index < length) {

internal/baseAssign.js

@@ -1,27 +1,6 @@
 var baseCopy = require('./baseCopy'),
-    getSymbols = require('./getSymbols'),
-    isNative = require('../lang/isNative'),
     keys = require('../object/keys');
 
-/** Native method references. */
-var preventExtensions = isNative(Object.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 in strict mode.
-  var object = { '1': 0 },
-      func = preventExtensions && isNative(func = Object.assign) && func;
-
-  try { func(preventExtensions(object), 'xo'); } catch(e) {}
-  return !object[1] && func;
-}());
-
 /**
  * The base implementation of `_.assign` without support for argument juggling,
  * multiple sources, and `customizer` functions.
@@ -31,10 +10,10 @@ var nativeAssign = (function() {
  * @param {Object} source The source object.
  * @returns {Object} Returns `object`.
  */
-var baseAssign = nativeAssign || function(object, source) {
+function baseAssign(object, source) {
   return source == null
     ? object
-    : baseCopy(source, getSymbols(source), baseCopy(source, keys(source), object));
-};
+    : baseCopy(source, keys(source), object);
+}
 
 module.exports = baseAssign;

internal/baseAt.js

@@ -1,5 +1,5 @@
-var isIndex = require('./isIndex'),
-    isLength = require('./isLength');
+var isArrayLike = require('./isArrayLike'),
+    isIndex = require('./isIndex');
 
 /**
  * The base implementation of `_.at` without support for string collections
@@ -12,8 +12,9 @@ var isIndex = require('./isIndex'),
  */
 function baseAt(collection, props) {
   var index = -1,
-      length = collection.length,
-      isArr = isLength(length),
+      isNil = collection == null,
+      isArr = !isNil && isArrayLike(collection),
+      length = isArr ? collection.length : 0,
       propsLength = props.length,
       result = Array(propsLength);
 
@@ -22,7 +23,7 @@ function baseAt(collection, props) {
     if (isArr) {
       result[index] = isIndex(key, length) ? collection[key] : undefined;
     } else {
-      result[index] = collection[key];
+      result[index] = isNil ? undefined : collection[key];
     }
   }
   return result;

internal/baseClone.js

@@ -53,7 +53,7 @@ cloneableTags[weakMapTag] = false;
 var objectProto = Object.prototype;
 
 /**
- * Used to resolve the [`toStringTag`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-object.prototype.tostring)
+ * Used to resolve the [`toStringTag`](http://ecma-international.org/ecma-262/6.0/#sec-object.prototype.tostring)
  * of values.
  */
 var objToString = objectProto.toString;
@@ -104,7 +104,7 @@ function baseClone(value, isDeep, customizer, key, object, stackA, stackB) {
         : (object ? value : {});
     }
   }
-  // Check for circular references and return corresponding clone.
+  // Check for circular references and return its corresponding clone.
   stackA || (stackA = []);
   stackB || (stackB = []);
 

internal/baseCompareAscending.js

@@ -3,19 +3,28 @@
  * sorts them in ascending order without guaranteeing a stable sort.
  *
  * @private
- * @param {*} value The value to compare to `other`.
- * @param {*} other The value to compare to `value`.
+ * @param {*} value The value to compare.
+ * @param {*} other The other value to compare.
  * @returns {number} Returns the sort order indicator for `value`.
  */
 function baseCompareAscending(value, other) {
   if (value !== other) {
-    var valIsReflexive = value === value,
+    var valIsNull = value === null,
+        valIsUndef = value === undefined,
+        valIsReflexive = value === value;
+
+    var othIsNull = other === null,
+        othIsUndef = other === undefined,
         othIsReflexive = other === other;
 
-    if (value > other || !valIsReflexive || (value === undefined && othIsReflexive)) {
+    if ((value > other && !othIsNull) || !valIsReflexive ||
+        (valIsNull && !othIsUndef && othIsReflexive) ||
+        (valIsUndef && othIsReflexive)) {
       return 1;
     }
-    if (value < other || !othIsReflexive || (other === undefined && valIsReflexive)) {
+    if ((value < other && !valIsNull) || !othIsReflexive ||
+        (othIsNull && !valIsUndef && valIsReflexive) ||
+        (othIsUndef && valIsReflexive)) {
       return -1;
     }
   }

internal/baseCreate.js

@@ -9,14 +9,14 @@ var isObject = require('../lang/isObject');
  * @returns {Object} Returns the new object.
  */
 var baseCreate = (function() {
-  function Object() {}
+  function object() {}
   return function(prototype) {
     if (isObject(prototype)) {
-      Object.prototype = prototype;
-      var result = new Object;
-      Object.prototype = null;
+      object.prototype = prototype;
+      var result = new object;
+      object.prototype = undefined;
     }
-    return result || global.Object();
+    return result || {};
   };
 }());
 

internal/baseDifference.js

@@ -2,6 +2,9 @@ var baseIndexOf = require('./baseIndexOf'),
     cacheIndexOf = require('./cacheIndexOf'),
     createCache = require('./createCache');
 
+/** Used as the size to enable large array optimizations. */
+var LARGE_ARRAY_SIZE = 200;
+
 /**
  * The base implementation of `_.difference` which accepts a single array
  * of values to exclude.
@@ -21,7 +24,7 @@ function baseDifference(array, values) {
   var index = -1,
       indexOf = baseIndexOf,
       isCommon = true,
-      cache = (isCommon && values.length >= 200) ? createCache(values) : null,
+      cache = (isCommon && values.length >= LARGE_ARRAY_SIZE) ? createCache(values) : null,
       valuesLength = values.length;
 
   if (cache) {

internal/baseExtremum.js

@@ -1,30 +1,24 @@
 var baseEach = require('./baseEach');
 
-/** Used as references for `-Infinity` and `Infinity`. */
-var NEGATIVE_INFINITY = Number.NEGATIVE_INFINITY,
-    POSITIVE_INFINITY = Number.POSITIVE_INFINITY;
-
 /**
  * Gets the extremum value of `collection` invoking `iteratee` for each value
  * in `collection` to generate the criterion by which the value is ranked.
- * The `iteratee` is invoked with three arguments: (value, index, collection).
+ * The `iteratee` is invoked with three arguments: (value, index|key, collection).
  *
  * @private
  * @param {Array|Object|string} collection The collection to iterate over.
  * @param {Function} iteratee The function invoked per iteration.
- * @param {boolean} [isMin] Specify returning the minimum, instead of the
- *  maximum, extremum value.
+ * @param {Function} comparator The function used to compare values.
+ * @param {*} exValue The initial extremum value.
  * @returns {*} Returns the extremum value.
  */
-function extremumBy(collection, iteratee, isMin) {
-  var exValue = isMin ? POSITIVE_INFINITY : NEGATIVE_INFINITY,
-      computed = exValue,
+function baseExtremum(collection, iteratee, comparator, exValue) {
+  var computed = exValue,
       result = computed;
 
   baseEach(collection, function(value, index, collection) {
-    var current = iteratee(value, index, collection);
-    if ((isMin ? (current < computed) : (current > computed)) ||
-        (current === exValue && current === result)) {
+    var current = +iteratee(value, index, collection);
+    if (comparator(current, computed) || (current === exValue && current === result)) {
       computed = current;
       result = value;
     }
@@ -32,4 +26,4 @@ function extremumBy(collection, iteratee, isMin) {
   return result;
 }
 
-module.exports = extremumBy;
+module.exports = baseExtremum;

internal/baseFlatten.js

@@ -1,6 +1,7 @@
-var isArguments = require('../lang/isArguments'),
+var arrayPush = require('./arrayPush'),
+    isArguments = require('../lang/isArguments'),
     isArray = require('../lang/isArray'),
-    isLength = require('./isLength'),
+    isArrayLike = require('./isArrayLike'),
     isObjectLike = require('./isObjectLike');
 
 /**
@@ -9,33 +10,29 @@ var isArguments = require('../lang/isArguments'),
  *
  * @private
  * @param {Array} array The array to flatten.
- * @param {boolean} isDeep Specify a deep flatten.
- * @param {boolean} isStrict Restrict flattening to arrays and `arguments` objects.
+ * @param {boolean} [isDeep] Specify a deep flatten.
+ * @param {boolean} [isStrict] Restrict flattening to arrays-like objects.
+ * @param {Array} [result=[]] The initial result value.
  * @returns {Array} Returns the new flattened array.
  */
-function baseFlatten(array, isDeep, isStrict) {
+function baseFlatten(array, isDeep, isStrict, result) {
+  result || (result = []);
+
   var index = -1,
-      length = array.length,
-      resIndex = -1,
-      result = [];
+      length = array.length;
 
   while (++index < length) {
     var value = array[index];
-
-    if (isObjectLike(value) && isLength(value.length) && (isArray(value) || isArguments(value))) {
+    if (isObjectLike(value) && isArrayLike(value) &&
+        (isStrict || isArray(value) || isArguments(value))) {
       if (isDeep) {
         // Recursively flatten arrays (susceptible to call stack limits).
-        value = baseFlatten(value, isDeep, isStrict);
-      }
-      var valIndex = -1,
-          valLength = value.length;
-
-      result.length += valLength;
-      while (++valIndex < valLength) {
-        result[++resIndex] = value[valIndex];
+        baseFlatten(value, isDeep, isStrict, result);
+      } else {
+        arrayPush(result, value);
       }
     } else if (!isStrict) {
-      result[++resIndex] = value;
+      result[result.length] = value;
     }
   }
   return result;

internal/baseGet.js

@@ -17,13 +17,13 @@ function baseGet(object, path, pathKey) {
   if (pathKey !== undefined && pathKey in toObject(object)) {
     path = [pathKey];
   }
-  var index = -1,
+  var index = 0,
       length = path.length;
 
-  while (object != null && ++index < length) {
-    var result = object = object[path[index]];
+  while (object != null && index < length) {
+    object = object[path[index++]];
   }
-  return result;
+  return (index && index == length) ? object : undefined;
 }
 
 module.exports = baseGet;

internal/baseIsEqual.js

@@ -1,4 +1,6 @@
-var baseIsEqualDeep = require('./baseIsEqualDeep');
+var baseIsEqualDeep = require('./baseIsEqualDeep'),
+    isObject = require('../lang/isObject'),
+    isObjectLike = require('./isObjectLike');
 
 /**
  * The base implementation of `_.isEqual` without support for `this` binding
@@ -14,18 +16,10 @@ var baseIsEqualDeep = require('./baseIsEqualDeep');
  * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
  */
 function baseIsEqual(value, other, customizer, isLoose, stackA, stackB) {
-  // Exit early for identical values.
   if (value === other) {
-    // Treat `+0` vs. `-0` as not equal.
-    return value !== 0 || (1 / value == 1 / other);
+    return true;
   }
-  var valType = typeof value,
-      othType = typeof other;
-
-  // Exit early for unlike primitive values.
-  if ((valType != 'function' && valType != 'object' && othType != 'function' && othType != 'object') ||
-      value == null || other == null) {
-    // Return `false` unless both values are `NaN`.
+  if (value == null || other == null || (!isObject(value) && !isObjectLike(other))) {
     return value !== value && other !== other;
   }
   return baseIsEqualDeep(value, other, baseIsEqual, customizer, isLoose, stackA, stackB);

internal/baseIsEqualDeep.js

@@ -16,7 +16,7 @@ var objectProto = Object.prototype;
 var hasOwnProperty = objectProto.hasOwnProperty;
 
 /**
- * Used to resolve the [`toStringTag`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-object.prototype.tostring)
+ * Used to resolve the [`toStringTag`](http://ecma-international.org/ecma-262/6.0/#sec-object.prototype.tostring)
  * of values.
  */
 var objToString = objectProto.toString;
@@ -66,11 +66,11 @@ function baseIsEqualDeep(object, other, equalFunc, customizer, isLoose, stackA,
     return equalByTag(object, other, objTag);
   }
   if (!isLoose) {
-    var valWrapped = objIsObj && hasOwnProperty.call(object, '__wrapped__'),
-        othWrapped = othIsObj && hasOwnProperty.call(other, '__wrapped__');
+    var objIsWrapped = objIsObj && hasOwnProperty.call(object, '__wrapped__'),
+        othIsWrapped = othIsObj && hasOwnProperty.call(other, '__wrapped__');
 
-    if (valWrapped || othWrapped) {
-      return equalFunc(valWrapped ? object.value() : object, othWrapped ? other.value() : other, customizer, isLoose, stackA, stackB);
+    if (objIsWrapped || othIsWrapped) {
+      return equalFunc(objIsWrapped ? object.value() : object, othIsWrapped ? other.value() : other, customizer, isLoose, stackA, stackB);
     }
   }
   if (!isSameTag) {

internal/baseIsMatch.js

@@ -1,4 +1,5 @@
-var baseIsEqual = require('./baseIsEqual');
+var baseIsEqual = require('./baseIsEqual'),
+    toObject = require('./toObject');
 
 /**
  * The base implementation of `_.isMatch` without support for callback
@@ -6,41 +7,43 @@ var baseIsEqual = require('./baseIsEqual');
  *
  * @private
  * @param {Object} object The object to inspect.
- * @param {Array} props The source property names to match.
- * @param {Array} values The source values to match.
- * @param {Array} strictCompareFlags Strict comparison flags for source values.
+ * @param {Array} matchData The propery names, values, and compare flags to match.
  * @param {Function} [customizer] The function to customize comparing objects.
  * @returns {boolean} Returns `true` if `object` is a match, else `false`.
  */
-function baseIsMatch(object, props, values, strictCompareFlags, customizer) {
-  var index = -1,
-      length = props.length,
+function baseIsMatch(object, matchData, customizer) {
+  var index = matchData.length,
+      length = index,
       noCustomizer = !customizer;
 
-  while (++index < length) {
-    if ((noCustomizer && strictCompareFlags[index])
-          ? values[index] !== object[props[index]]
-          : !(props[index] in object)
+  if (object == null) {
+    return !length;
+  }
+  object = toObject(object);
+  while (index--) {
+    var data = matchData[index];
+    if ((noCustomizer && data[2])
+          ? data[1] !== object[data[0]]
+          : !(data[0] in object)
         ) {
       return false;
     }
   }
-  index = -1;
   while (++index < length) {
-    var key = props[index],
+    data = matchData[index];
+    var key = data[0],
         objValue = object[key],
-        srcValue = values[index];
+        srcValue = data[1];
 
-    if (noCustomizer && strictCompareFlags[index]) {
-      var result = objValue !== undefined || (key in object);
-    } else {
-      result = customizer ? customizer(objValue, srcValue, key) : undefined;
-      if (result === undefined) {
-        result = baseIsEqual(srcValue, objValue, customizer, true);
+    if (noCustomizer && data[2]) {
+      if (objValue === undefined && !(key in object)) {
+        return false;
+      }
+    } else {
+      var result = customizer ? customizer(objValue, srcValue, key) : undefined;
+      if (!(result === undefined ? baseIsEqual(srcValue, objValue, customizer, true) : result)) {
+        return false;
       }
-    }
-    if (!result) {
-      return false;
     }
   }
   return true;

internal/baseMap.js

@@ -1,6 +1,5 @@
 var baseEach = require('./baseEach'),
-    getLength = require('./getLength'),
-    isLength = require('./isLength');
+    isArrayLike = require('./isArrayLike');
 
 /**
  * The base implementation of `_.map` without support for callback shorthands
@@ -13,8 +12,7 @@ var baseEach = require('./baseEach'),
  */
 function baseMap(collection, iteratee) {
   var index = -1,
-      length = getLength(collection),
-      result = isLength(length) ? Array(length) : [];
+      result = isArrayLike(collection) ? Array(collection.length) : [];
 
   baseEach(collection, function(value, key, collection) {
     result[++index] = iteratee(value, key, collection);

internal/baseMatches.js

@@ -1,7 +1,5 @@
 var baseIsMatch = require('./baseIsMatch'),
-    constant = require('../utility/constant'),
-    isStrictComparable = require('./isStrictComparable'),
-    keys = require('../object/keys'),
+    getMatchData = require('./getMatchData'),
     toObject = require('./toObject');
 
 /**
@@ -12,35 +10,20 @@ var baseIsMatch = require('./baseIsMatch'),
  * @returns {Function} Returns the new function.
  */
 function baseMatches(source) {
-  var props = keys(source),
-      length = props.length;
+  var matchData = getMatchData(source);
+  if (matchData.length == 1 && matchData[0][2]) {
+    var key = matchData[0][0],
+        value = matchData[0][1];
 
-  if (!length) {
-    return constant(true);
-  }
-  if (length == 1) {
-    var key = props[0],
-        value = source[key];
-
-    if (isStrictComparable(value)) {
-      return function(object) {
-        if (object == null) {
-          return false;
-        }
-        return object[key] === value && (value !== undefined || (key in toObject(object)));
-      };
-    }
-  }
-  var values = Array(length),
-      strictCompareFlags = Array(length);
-
-  while (length--) {
-    value = source[props[length]];
-    values[length] = value;
-    strictCompareFlags[length] = isStrictComparable(value);
+    return function(object) {
+      if (object == null) {
+        return false;
+      }
+      return object[key] === value && (value !== undefined || (key in toObject(object)));
+    };
   }
   return function(object) {
-    return object != null && baseIsMatch(toObject(object), props, values, strictCompareFlags);
+    return baseIsMatch(object, matchData);
   };
 }
 

internal/baseMatchesProperty.js

@@ -9,17 +9,16 @@ var baseGet = require('./baseGet'),
     toPath = require('./toPath');
 
 /**
- * The base implementation of `_.matchesProperty` which does not which does
- * not clone `value`.
+ * The base implementation of `_.matchesProperty` which does not clone `srcValue`.
  *
  * @private
  * @param {string} path The path of the property to get.
- * @param {*} value The value to compare.
+ * @param {*} srcValue The value to compare.
  * @returns {Function} Returns the new function.
  */
-function baseMatchesProperty(path, value) {
+function baseMatchesProperty(path, srcValue) {
   var isArr = isArray(path),
-      isCommon = isKey(path) && isStrictComparable(value),
+      isCommon = isKey(path) && isStrictComparable(srcValue),
       pathKey = (path + '');
 
   path = toPath(path);
@@ -37,9 +36,9 @@ function baseMatchesProperty(path, value) {
       key = last(path);
       object = toObject(object);
     }
-    return object[key] === value
-      ? (value !== undefined || (key in object))
-      : baseIsEqual(value, object[key], null, true);
+    return object[key] === srcValue
+      ? (srcValue !== undefined || (key in object))
+      : baseIsEqual(srcValue, object[key], undefined, true);
   };
 }
 

internal/baseMerge.js

@@ -1,19 +1,12 @@
 var arrayEach = require('./arrayEach'),
     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'),
     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,
  * multiple sources, and `this` binding `customizer` functions.
@@ -21,7 +14,7 @@ var push = arrayProto.push;
  * @private
  * @param {Object} object The destination object.
  * @param {Object} source The source object.
- * @param {Function} [customizer] The function to customize merging properties.
+ * @param {Function} [customizer] The function to customize merged values.
  * @param {Array} [stackA=[]] Tracks traversed source objects.
  * @param {Array} [stackB=[]] Associates values with source counterparts.
  * @returns {Object} Returns `object`.
@@ -30,11 +23,9 @@ function baseMerge(object, source, customizer, stackA, stackB) {
   if (!isObject(object)) {
     return object;
   }
-  var isSrcArr = isLength(source.length) && (isArray(source) || isTypedArray(source));
-  if (!isSrcArr) {
-    var props = keys(source);
-    push.apply(props, getSymbols(source));
-  }
+  var isSrcArr = isArrayLike(source) && (isArray(source) || isTypedArray(source)),
+      props = isSrcArr ? undefined : keys(source);
+
   arrayEach(props || source, function(srcValue, key) {
     if (props) {
       key = srcValue;
@@ -53,7 +44,7 @@ function baseMerge(object, source, customizer, stackA, stackB) {
       if (isCommon) {
         result = srcValue;
       }
-      if ((isSrcArr || result !== undefined) &&
+      if ((result !== undefined || (isSrcArr && !(key in object))) &&
           (isCommon || (result === result ? (result !== value) : (value === value)))) {
         object[key] = result;
       }

internal/baseMergeDeep.js

@@ -1,8 +1,7 @@
 var arrayCopy = require('./arrayCopy'),
-    getLength = require('./getLength'),
     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');
@@ -17,7 +16,7 @@ var arrayCopy = require('./arrayCopy'),
  * @param {Object} source The source object.
  * @param {string} key The key of the value to merge.
  * @param {Function} mergeFunc The function to merge values.
- * @param {Function} [customizer] The function to customize merging properties.
+ * @param {Function} [customizer] The function to customize merged values.
  * @param {Array} [stackA=[]] Tracks traversed source objects.
  * @param {Array} [stackB=[]] Associates values with source counterparts.
  * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
@@ -38,10 +37,10 @@ function baseMergeDeep(object, source, key, mergeFunc, customizer, stackA, stack
 
   if (isCommon) {
     result = srcValue;
-    if (isLength(srcValue.length) && (isArray(srcValue) || isTypedArray(srcValue))) {
+    if (isArrayLike(srcValue) && (isArray(srcValue) || isTypedArray(srcValue))) {
       result = isArray(value)
         ? value
-        : (getLength(value) ? arrayCopy(value) : []);
+        : (isArrayLike(value) ? arrayCopy(value) : []);
     }
     else if (isPlainObject(srcValue) || isArguments(srcValue)) {
       result = isArguments(value)

internal/basePullAt.js

@@ -16,9 +16,9 @@ var splice = arrayProto.splice;
  * @returns {Array} Returns `array`.
  */
 function basePullAt(array, indexes) {
-  var length = indexes.length;
+  var length = array ? indexes.length : 0;
   while (length--) {
-    var index = parseFloat(indexes[length]);
+    var index = indexes[length];
     if (index != previous && isIndex(index)) {
       var previous = index;
       splice.call(array, index, 1);

internal/baseRandom.js

@@ -1,8 +1,6 @@
-/** Native method references. */
-var floor = Math.floor;
-
 /* Native method references for those with the same name as other `lodash` methods. */
-var nativeRandom = Math.random;
+var nativeFloor = Math.floor,
+    nativeRandom = Math.random;
 
 /**
  * The base implementation of `_.random` without support for argument juggling
@@ -14,7 +12,7 @@ var nativeRandom = Math.random;
  * @returns {number} Returns the random number.
  */
 function baseRandom(min, max) {
-  return min + floor(nativeRandom() * (max - min + 1));
+  return min + nativeFloor(nativeRandom() * (max - min + 1));
 }
 
 module.exports = baseRandom;

internal/baseToString.js

@@ -1,5 +1,5 @@
 /**
- * Converts `value` to a string if it is not one. An empty string is returned
+ * Converts `value` to a string if it's not one. An empty string is returned
  * for `null` or `undefined` values.
  *
  * @private
@@ -7,9 +7,6 @@
  * @returns {string} Returns the string.
  */
 function baseToString(value) {
-  if (typeof value == 'string') {
-    return value;
-  }
   return value == null ? '' : (value + '');
 }
 

internal/baseUniq.js

@@ -2,6 +2,9 @@ var baseIndexOf = require('./baseIndexOf'),
     cacheIndexOf = require('./cacheIndexOf'),
     createCache = require('./createCache');
 
+/** Used as the size to enable large array optimizations. */
+var LARGE_ARRAY_SIZE = 200;
+
 /**
  * The base implementation of `_.uniq` without support for callback shorthands
  * and `this` binding.
@@ -16,7 +19,7 @@ function baseUniq(array, iteratee) {
       indexOf = baseIndexOf,
       length = array.length,
       isCommon = true,
-      isLarge = isCommon && length >= 200,
+      isLarge = isCommon && length >= LARGE_ARRAY_SIZE,
       seen = isLarge ? createCache() : null,
       result = [];
 

internal/baseWrapperValue.js

@@ -1,10 +1,5 @@
-var LazyWrapper = require('./LazyWrapper');
-
-/** Used for native method references. */
-var arrayProto = Array.prototype;
-
-/** Native method references. */
-var push = arrayProto.push;
+var LazyWrapper = require('./LazyWrapper'),
+    arrayPush = require('./arrayPush');
 
 /**
  * The base implementation of `wrapperValue` which returns the result of
@@ -25,11 +20,8 @@ function baseWrapperValue(value, actions) {
       length = actions.length;
 
   while (++index < length) {
-    var args = [result],
-        action = actions[index];
-
-    push.apply(args, action.args);
-    result = action.func.apply(action.thisArg, args);
+    var action = actions[index];
+    result = action.func.apply(action.thisArg, arrayPush([result], action.args));
   }
   return result;
 }

internal/binaryIndex.js

@@ -2,7 +2,7 @@ var binaryIndexBy = require('./binaryIndexBy'),
     identity = require('../utility/identity');
 
 /** Used as references for the maximum length and index of an array. */
-var MAX_ARRAY_LENGTH = Math.pow(2, 32) - 1,
+var MAX_ARRAY_LENGTH = 4294967295,
     HALF_MAX_ARRAY_LENGTH = MAX_ARRAY_LENGTH >>> 1;
 
 /**
@@ -25,7 +25,7 @@ function binaryIndex(array, value, retHighest) {
       var mid = (low + high) >>> 1,
           computed = array[mid];
 
-      if (retHighest ? (computed <= value) : (computed < value)) {
+      if ((retHighest ? (computed <= value) : (computed < value)) && computed !== null) {
         low = mid + 1;
       } else {
         high = mid;

internal/binaryIndexBy.js

@@ -1,12 +1,10 @@
-/** Native method references. */
-var floor = Math.floor;
-
 /* Native method references for those with the same name as other `lodash` methods. */
-var nativeMin = Math.min;
+var nativeFloor = Math.floor,
+    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;
+var MAX_ARRAY_LENGTH = 4294967295,
+    MAX_ARRAY_INDEX = MAX_ARRAY_LENGTH - 1;
 
 /**
  * This function is like `binaryIndex` except that it invokes `iteratee` for
@@ -27,17 +25,23 @@ function binaryIndexBy(array, value, iteratee, retHighest) {
   var low = 0,
       high = array ? array.length : 0,
       valIsNaN = value !== value,
+      valIsNull = value === null,
       valIsUndef = value === undefined;
 
   while (low < high) {
-    var mid = floor((low + high) / 2),
+    var mid = nativeFloor((low + high) / 2),
         computed = iteratee(array[mid]),
+        isDef = computed !== undefined,
         isReflexive = computed === computed;
 
     if (valIsNaN) {
       var setLow = isReflexive || retHighest;
+    } else if (valIsNull) {
+      setLow = isReflexive && isDef && (retHighest || computed != null);
     } else if (valIsUndef) {
-      setLow = isReflexive && (retHighest || computed !== undefined);
+      setLow = isReflexive && (retHighest || isDef);
+    } else if (computed == null) {
+      setLow = false;
     } else {
       setLow = retHighest ? (computed <= value) : (computed < value);
     }

internal/bufferClone.js

@@ -1,26 +1,6 @@
-var constant = require('../utility/constant'),
-    isNative = require('../lang/isNative');
-
 /** Native method references. */
-var ArrayBuffer = isNative(ArrayBuffer = global.ArrayBuffer) && ArrayBuffer,
-    bufferSlice = isNative(bufferSlice = ArrayBuffer && new ArrayBuffer(0).slice) && bufferSlice,
-    floor = Math.floor,
-    Uint8Array = isNative(Uint8Array = global.Uint8Array) && Uint8Array;
-
-/** Used to clone array buffers. */
-var Float64Array = (function() {
-  // Safari 5 errors when using an array buffer to initialize a typed array
-  // where the array buffer's `byteLength` is not a multiple of the typed
-  // array's `BYTES_PER_ELEMENT`.
-  try {
-    var func = isNative(func = global.Float64Array) && func,
-        result = new func(new ArrayBuffer(10), 0, 1) && func;
-  } catch(e) {}
-  return result;
-}());
-
-/** Used as the size, in bytes, of each `Float64Array` element. */
-var FLOAT64_BYTES_PER_ELEMENT = Float64Array ? Float64Array.BYTES_PER_ELEMENT : 0;
+var ArrayBuffer = global.ArrayBuffer,
+    Uint8Array = global.Uint8Array;
 
 /**
  * Creates a clone of the given array buffer.
@@ -30,26 +10,11 @@ var FLOAT64_BYTES_PER_ELEMENT = Float64Array ? Float64Array.BYTES_PER_ELEMENT :
  * @returns {ArrayBuffer} Returns the cloned array buffer.
  */
 function bufferClone(buffer) {
-  return bufferSlice.call(buffer, 0);
-}
-if (!bufferSlice) {
-  // PhantomJS has `ArrayBuffer` and `Uint8Array` but not `Float64Array`.
-  bufferClone = !(ArrayBuffer && Uint8Array) ? constant(null) : function(buffer) {
-    var byteLength = buffer.byteLength,
-        floatLength = Float64Array ? floor(byteLength / FLOAT64_BYTES_PER_ELEMENT) : 0,
-        offset = floatLength * FLOAT64_BYTES_PER_ELEMENT,
-        result = new ArrayBuffer(byteLength);
+  var result = new ArrayBuffer(buffer.byteLength),
+      view = new Uint8Array(result);
 
-    if (floatLength) {
-      var view = new Float64Array(result, 0, floatLength);
-      view.set(new Float64Array(buffer, 0, floatLength));
-    }
-    if (byteLength != offset) {
-      view = new Uint8Array(result, offset);
-      view.set(new Uint8Array(buffer, offset));
-    }
-    return result;
-  };
+  view.set(new Uint8Array(buffer));
+  return result;
 }
 
 module.exports = bufferClone;

internal/charAtCallback.js

@@ -1,12 +0,0 @@
-/**
- * Used by `_.max` and `_.min` as the default callback for string values.
- *
- * @private
- * @param {string} string The string to inspect.
- * @returns {number} Returns the code unit of the first character of the string.
- */
-function charAtCallback(string) {
-  return string.charCodeAt(0);
-}
-
-module.exports = charAtCallback;

internal/compareAscending.js

@@ -5,8 +5,8 @@ var baseCompareAscending = require('./baseCompareAscending');
  * sort them in ascending order.
  *
  * @private
- * @param {Object} object The object to compare to `other`.
- * @param {Object} other The object to compare to `object`.
+ * @param {Object} object The object to compare.
+ * @param {Object} other The other object to compare.
  * @returns {number} Returns the sort order indicator for `object`.
  */
 function compareAscending(object, other) {

internal/compareMultiple.js

@@ -1,16 +1,16 @@
 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:
+ * Used by `_.sortByOrder` to compare multiple properties of a value to another
+ * and stable sort them.
  *
- * 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.
+ * If `orders` is unspecified, all valuess are sorted in ascending order. Otherwise,
+ * a value is sorted in ascending order if its corresponding order is "asc", and
+ * descending if "desc".
  *
  * @private
- * @param {Object} object The object to compare to `other`.
- * @param {Object} other The object to compare to `object`.
+ * @param {Object} object The object to compare.
+ * @param {Object} other The other object to compare.
  * @param {boolean[]} orders The order to sort by for each property.
  * @returns {number} Returns the sort order indicator for `object`.
  */
@@ -27,7 +27,8 @@ function compareMultiple(object, other, orders) {
       if (index >= ordersLength) {
         return result;
       }
-      return result * (orders[index] ? 1 : -1);
+      var order = orders[index];
+      return result * ((order === 'asc' || order === true) ? 1 : -1);
     }
   }
   // Fixes an `Array#sort` bug in the JS engine embedded in Adobe applications

internal/composeArgs.js

@@ -17,7 +17,7 @@ function composeArgs(args, partials, holders) {
       argsLength = nativeMax(args.length - holdersLength, 0),
       leftIndex = -1,
       leftLength = partials.length,
-      result = Array(argsLength + leftLength);
+      result = Array(leftLength + argsLength);
 
   while (++leftIndex < leftLength) {
     result[leftIndex] = partials[leftIndex];

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/createAggregator.js

@@ -3,12 +3,7 @@ var baseCallback = require('./baseCallback'),
     isArray = require('../lang/isArray');
 
 /**
- * Creates a function that aggregates a collection, creating an accumulator
- * object composed from the results of running each element in the collection
- * through an iteratee.
- *
- * **Note:** This function is used to create `_.countBy`, `_.groupBy`, `_.indexBy`,
- * and `_.partition`.
+ * Creates a `_.countBy`, `_.groupBy`, `_.indexBy`, or `_.partition` function.
  *
  * @private
  * @param {Function} setter The function to set keys and values of the accumulator object.

internal/createAssigner.js

@@ -3,10 +3,7 @@ var bindCallback = require('./bindCallback'),
     restParam = require('../function/restParam');
 
 /**
- * Creates a function that assigns properties of source object(s) to a given
- * destination object.
- *
- * **Note:** This function is used to create `_.assign`, `_.defaults`, and `_.merge`.
+ * Creates a `_.assign`, `_.defaults`, or `_.merge` function.
  *
  * @private
  * @param {Function} assigner The function to assign values.
@@ -16,19 +13,19 @@ function createAssigner(assigner) {
   return restParam(function(object, sources) {
     var index = -1,
         length = object == null ? 0 : sources.length,
-        customizer = length > 2 && sources[length - 2],
-        guard = length > 2 && sources[2],
-        thisArg = length > 1 && sources[length - 1];
+        customizer = length > 2 ? sources[length - 2] : undefined,
+        guard = length > 2 ? sources[2] : undefined,
+        thisArg = length > 1 ? sources[length - 1] : undefined;
 
     if (typeof customizer == 'function') {
       customizer = bindCallback(customizer, thisArg, 5);
       length -= 2;
     } else {
-      customizer = typeof thisArg == 'function' ? thisArg : null;
+      customizer = typeof thisArg == 'function' ? thisArg : undefined;
       length -= (customizer ? 1 : 0);
     }
     if (guard && isIterateeCall(sources[0], sources[1], guard)) {
-      customizer = length < 3 ? null : customizer;
+      customizer = length < 3 ? undefined : customizer;
       length = 1;
     }
     while (++index < length) {

internal/createCache.js

@@ -1,12 +1,11 @@
 var SetCache = require('./SetCache'),
-    constant = require('../utility/constant'),
-    isNative = require('../lang/isNative');
+    getNative = require('./getNative');
 
 /** Native method references. */
-var Set = isNative(Set = global.Set) && Set;
+var Set = getNative(global, 'Set');
 
 /* Native method references for those with the same name as other `lodash` methods. */
-var nativeCreate = isNative(nativeCreate = Object.create) && nativeCreate;
+var nativeCreate = getNative(Object, 'create');
 
 /**
  * Creates a `Set` cache object to optimize linear searches of large arrays.
@@ -15,8 +14,8 @@ var nativeCreate = isNative(nativeCreate = Object.create) && nativeCreate;
  * @param {Array} [values] The values to cache.
  * @returns {null|Object} Returns the new cache object if `Set` is supported, else `null`.
  */
-var createCache = !(nativeCreate && Set) ? constant(null) : function(values) {
-  return new SetCache(values);
-};
+function createCache(values) {
+  return (nativeCreate && Set) ? new SetCache(values) : null;
+}
 
 module.exports = createCache;

internal/createCtorWrapper.js

@@ -11,8 +11,22 @@ var baseCreate = require('./baseCreate'),
  */
 function createCtorWrapper(Ctor) {
   return function() {
+    // Use a `switch` statement to work with class constructors.
+    // See http://ecma-international.org/ecma-262/6.0/#sec-ecmascript-function-objects-call-thisargument-argumentslist
+    // for more details.
+    var args = arguments;
+    switch (args.length) {
+      case 0: return new Ctor;
+      case 1: return new Ctor(args[0]);
+      case 2: return new Ctor(args[0], args[1]);
+      case 3: return new Ctor(args[0], args[1], args[2]);
+      case 4: return new Ctor(args[0], args[1], args[2], args[3]);
+      case 5: return new Ctor(args[0], args[1], args[2], args[3], args[4]);
+      case 6: return new Ctor(args[0], args[1], args[2], args[3], args[4], args[5]);
+      case 7: return new Ctor(args[0], args[1], args[2], args[3], args[4], args[5], args[6]);
+    }
     var thisBinding = baseCreate(Ctor.prototype),
-        result = Ctor.apply(thisBinding, arguments);
+        result = Ctor.apply(thisBinding, args);
 
     // Mimic the constructor's `return` behavior.
     // See https://es5.github.io/#x13.2.2 for more details.

internal/createCurry.js

@@ -11,9 +11,9 @@ var createWrapper = require('./createWrapper'),
 function createCurry(flag) {
   function curryFunc(func, arity, guard) {
     if (guard && isIterateeCall(func, arity, guard)) {
-      arity = null;
+      arity = undefined;
     }
-    var result = createWrapper(func, flag, null, null, null, null, null, arity);
+    var result = createWrapper(func, flag, undefined, undefined, undefined, undefined, undefined, arity);
     result.placeholder = curryFunc.placeholder;
     return result;
   }

internal/createDefaults.js

@@ -0,0 +1,22 @@
+var restParam = require('../function/restParam');
+
+/**
+ * Creates a `_.defaults` or `_.defaultsDeep` function.
+ *
+ * @private
+ * @param {Function} assigner The function to assign values.
+ * @param {Function} customizer The function to customize assigned values.
+ * @returns {Function} Returns the new defaults function.
+ */
+function createDefaults(assigner, customizer) {
+  return restParam(function(args) {
+    var object = args[0];
+    if (object == null) {
+      return object;
+    }
+    args.push(customizer);
+    return assigner.apply(undefined, args);
+  });
+}
+
+module.exports = createDefaults;

internal/createExtremum.js

@@ -1,37 +1,32 @@
-var baseCallback = require('./baseCallback'),
-    charAtCallback = require('./charAtCallback'),
-    extremumBy = require('./extremumBy'),
+var arrayExtremum = require('./arrayExtremum'),
+    baseCallback = require('./baseCallback'),
+    baseExtremum = require('./baseExtremum'),
     isArray = require('../lang/isArray'),
     isIterateeCall = require('./isIterateeCall'),
-    isString = require('../lang/isString'),
     toIterable = require('./toIterable');
 
 /**
  * Creates a `_.max` or `_.min` function.
  *
  * @private
- * @param {Function} arrayFunc The function to get the extremum value from an array.
- * @param {boolean} [isMin] Specify returning the minimum, instead of the maximum,
- *  extremum value.
+ * @param {Function} comparator The function used to compare values.
+ * @param {*} exValue The initial extremum value.
  * @returns {Function} Returns the new extremum function.
  */
-function createExtremum(arrayFunc, isMin) {
+function createExtremum(comparator, exValue) {
   return function(collection, iteratee, thisArg) {
     if (thisArg && isIterateeCall(collection, iteratee, thisArg)) {
-      iteratee = null;
+      iteratee = undefined;
     }
-    var noIteratee = iteratee == null;
-
-    iteratee = noIteratee ? iteratee : baseCallback(iteratee, thisArg, 3);
-    if (noIteratee) {
-      var isArr = isArray(collection);
-      if (!isArr && isString(collection)) {
-        iteratee = charAtCallback;
-      } else {
-        return arrayFunc(isArr ? collection : toIterable(collection));
+    iteratee = baseCallback(iteratee, thisArg, 3);
+    if (iteratee.length == 1) {
+      collection = isArray(collection) ? collection : toIterable(collection);
+      var result = arrayExtremum(collection, iteratee, comparator, exValue);
+      if (!(collection.length && result === exValue)) {
+        return result;
       }
     }
-    return extremumBy(collection, iteratee, isMin);
+    return baseExtremum(collection, iteratee, comparator, exValue);
   };
 }
 

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 +4,15 @@ 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 size to enable large array optimizations. */
+var LARGE_ARRAY_SIZE = 200;
+
 /** Used as the `TypeError` message for "Functions" methods. */
 var FUNC_ERROR_TEXT = 'Expected a function';
 
@@ -16,11 +25,8 @@ var FUNC_ERROR_TEXT = 'Expected a function';
  */
 function createFlow(fromRight) {
   return function() {
-    var length = arguments.length;
-    if (!length) {
-      return function() { return arguments[0]; };
-    }
     var wrapper,
+        length = arguments.length,
         index = fromRight ? length : -1,
         leftIndex = 0,
         funcs = Array(length);
@@ -30,28 +36,32 @@ function createFlow(fromRight) {
       if (typeof func != 'function') {
         throw new TypeError(FUNC_ERROR_TEXT);
       }
-      var funcName = wrapper ? '' : getFuncName(func);
-      wrapper = funcName == 'wrapper' ? new LodashWrapper([]) : wrapper;
+      if (!wrapper && LodashWrapper.prototype.thru && getFuncName(func) == 'wrapper') {
+        wrapper = new LodashWrapper([], true);
+      }
     }
     index = wrapper ? -1 : length;
     while (++index < length) {
       func = funcs[index];
-      funcName = getFuncName(func);
 
-      var data = funcName == 'wrapper' ? getData(func) : null;
-      if (data && isLaziable(data[0])) {
+      var funcName = getFuncName(func),
+          data = funcName == 'wrapper' ? getData(func) : undefined;
+
+      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);
       }
     }
     return function() {
-      var args = arguments;
-      if (wrapper && args.length == 1 && isArray(args[0])) {
-        return wrapper.plant(args[0]).value();
+      var args = arguments,
+          value = args[0];
+
+      if (wrapper && args.length == 1 && isArray(value) && value.length >= LARGE_ARRAY_SIZE) {
+        return wrapper.plant(value).value();
       }
       var index = 0,
-          result = funcs[index].apply(this, args);
+          result = length ? funcs[index].apply(this, args) : value;
 
       while (++index < length) {
         result = funcs[index].call(this, result);

internal/createHybridWrapper.js

@@ -43,10 +43,8 @@ function createHybridWrapper(func, bitmask, thisArg, partials, holders, partials
       isBindKey = bitmask & BIND_KEY_FLAG,
       isCurry = bitmask & CURRY_FLAG,
       isCurryBound = bitmask & CURRY_BOUND_FLAG,
-      isCurryRight = bitmask & CURRY_RIGHT_FLAG;
-
-  var Ctor = !isBindKey && createCtorWrapper(func),
-      key = func;
+      isCurryRight = bitmask & CURRY_RIGHT_FLAG,
+      Ctor = isBindKey ? undefined : createCtorWrapper(func);
 
   function wrapper() {
     // Avoid `arguments` object use disqualifying optimizations by
@@ -70,12 +68,12 @@ function createHybridWrapper(func, bitmask, thisArg, partials, holders, partials
 
       length -= argsHolders.length;
       if (length < arity) {
-        var newArgPos = argPos ? arrayCopy(argPos) : null,
+        var newArgPos = argPos ? arrayCopy(argPos) : undefined,
             newArity = nativeMax(arity - length, 0),
-            newsHolders = isCurry ? argsHolders : null,
-            newHoldersRight = isCurry ? null : argsHolders,
-            newPartials = isCurry ? args : null,
-            newPartialsRight = isCurry ? null : args;
+            newsHolders = isCurry ? argsHolders : undefined,
+            newHoldersRight = isCurry ? undefined : argsHolders,
+            newPartials = isCurry ? args : undefined,
+            newPartialsRight = isCurry ? undefined : args;
 
         bitmask |= (isCurry ? PARTIAL_FLAG : PARTIAL_RIGHT_FLAG);
         bitmask &= ~(isCurry ? PARTIAL_RIGHT_FLAG : PARTIAL_FLAG);
@@ -93,17 +91,18 @@ function createHybridWrapper(func, bitmask, thisArg, partials, holders, partials
         return result;
       }
     }
-    var thisBinding = isBind ? thisArg : this;
-    if (isBindKey) {
-      func = thisBinding[key];
-    }
+    var thisBinding = isBind ? thisArg : this,
+        fn = isBindKey ? thisBinding[func] : func;
+
     if (argPos) {
       args = reorder(args, argPos);
     }
     if (isAry && ary < args.length) {
       args.length = ary;
     }
-    var fn = (this && this !== global && this instanceof wrapper) ? (Ctor || createCtorWrapper(func)) : func;
+    if (this && this !== global && this instanceof wrapper) {
+      fn = Ctor || createCtorWrapper(func);
+    }
     return fn.apply(thisBinding, args);
   }
   return wrapper;

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/createPadding.js

@@ -1,10 +1,8 @@
 var repeat = require('../string/repeat');
 
-/** Native method references. */
-var ceil = Math.ceil;
-
 /* Native method references for those with the same name as other `lodash` methods. */
-var nativeIsFinite = global.isFinite;
+var nativeCeil = Math.ceil,
+    nativeIsFinite = global.isFinite;
 
 /**
  * Creates the padding required for `string` based on the given `length`.
@@ -25,7 +23,7 @@ function createPadding(string, length, chars) {
   }
   var padLength = length - strLength;
   chars = chars == null ? ' ' : (chars + '');
-  return repeat(chars, ceil(padLength / chars.length)).slice(0, padLength);
+  return repeat(chars, nativeCeil(padLength / chars.length)).slice(0, padLength);
 }
 
 module.exports = createPadding;

internal/createPartial.js

@@ -12,7 +12,7 @@ var createWrapper = require('./createWrapper'),
 function createPartial(flag) {
   var partialFunc = restParam(function(func, partials) {
     var holders = replaceHolders(partials, partialFunc.placeholder);
-    return createWrapper(func, flag, null, partials, holders);
+    return createWrapper(func, flag, undefined, partials, holders);
   });
   return partialFunc;
 }