diff --git a/README.md b/README.md
index dab4a6fe6..372d2e0f0 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-# lodash-amd v4.8.2
+# lodash-amd v4.9.0
 
 The [Lodash](https://lodash.com/) library exported as [AMD](https://github.com/amdjs/amdjs-api/wiki/AMD) modules.
 
@@ -27,4 +27,4 @@ require({
 });
 ```
 
-See the [package source](https://github.com/lodash/lodash/tree/4.8.2-amd) for more details.
+See the [package source](https://github.com/lodash/lodash/tree/4.9.0-amd) for more details.
diff --git a/_Hash.js b/_Hash.js
index b773cb614..09075f2f2 100644
--- a/_Hash.js
+++ b/_Hash.js
@@ -4,7 +4,7 @@ define(['./_nativeCreate'], function(nativeCreate) {
   var objectProto = Object.prototype;
 
   /**
-   * Creates an hash object.
+   * Creates a hash object.
    *
    * @private
    * @constructor
diff --git a/_baseFlatten.js b/_baseFlatten.js
index 8488c552a..77a83378d 100644
--- a/_baseFlatten.js
+++ b/_baseFlatten.js
@@ -1,4 +1,4 @@
-define(['./_arrayPush', './isArguments', './isArray', './isArrayLikeObject'], function(arrayPush, isArguments, isArray, isArrayLikeObject) {
+define(['./_arrayPush', './_isFlattenable'], function(arrayPush, isFlattenable) {
 
   /**
    * The base implementation of `_.flatten` with support for restricting flattening.
@@ -6,23 +6,24 @@ define(['./_arrayPush', './isArguments', './isArray', './isArrayLikeObject'], fu
    * @private
    * @param {Array} array The array to flatten.
    * @param {number} depth The maximum recursion depth.
-   * @param {boolean} [isStrict] Restrict flattening to arrays-like objects.
+   * @param {boolean} [predicate=isFlattenable] The function invoked per iteration.
+   * @param {boolean} [isStrict] Restrict to values that pass `predicate` checks.
    * @param {Array} [result=[]] The initial result value.
    * @returns {Array} Returns the new flattened array.
    */
-  function baseFlatten(array, depth, isStrict, result) {
-    result || (result = []);
-
+  function baseFlatten(array, depth, predicate, isStrict, result) {
     var index = -1,
         length = array.length;
 
+    predicate || (predicate = isFlattenable);
+    result || (result = []);
+
     while (++index < length) {
       var value = array[index];
-      if (depth > 0 && isArrayLikeObject(value) &&
-          (isStrict || isArray(value) || isArguments(value))) {
+      if (depth > 0 && predicate(value)) {
         if (depth > 1) {
           // Recursively flatten arrays (susceptible to call stack limits).
-          baseFlatten(value, depth - 1, isStrict, result);
+          baseFlatten(value, depth - 1, predicate, isStrict, result);
         } else {
           arrayPush(result, value);
         }
diff --git a/_createOver.js b/_createOver.js
index ca834ba30..1b817838d 100644
--- a/_createOver.js
+++ b/_createOver.js
@@ -1,4 +1,4 @@
-define(['./_apply', './_arrayMap', './_baseFlatten', './_baseIteratee', './rest'], function(apply, arrayMap, baseFlatten, baseIteratee, rest) {
+define(['./_apply', './_arrayMap', './_baseFlatten', './_baseIteratee', './_isFlattenableIteratee', './rest'], function(apply, arrayMap, baseFlatten, baseIteratee, isFlattenableIteratee, rest) {
 
   /**
    * Creates a function like `_.over`.
@@ -9,7 +9,7 @@ define(['./_apply', './_arrayMap', './_baseFlatten', './_baseIteratee', './rest'
    */
   function createOver(arrayFunc) {
     return rest(function(iteratees) {
-      iteratees = arrayMap(baseFlatten(iteratees, 1), baseIteratee);
+      iteratees = arrayMap(baseFlatten(iteratees, 1, isFlattenableIteratee), baseIteratee);
       return rest(function(args) {
         var thisArg = this;
         return arrayFunc(iteratees, function(iteratee) {
diff --git a/_getTag.js b/_getTag.js
index 4ba142f0a..872e4f8ea 100644
--- a/_getTag.js
+++ b/_getTag.js
@@ -1,5 +1,8 @@
 define(['./_DataView', './_Map', './_Promise', './_Set', './_WeakMap', './_toSource'], function(DataView, Map, Promise, Set, WeakMap, toSource) {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /** `Object#toString` result references. */
   var mapTag = '[object Map]',
       objectTag = '[object Object]',
@@ -46,8 +49,8 @@ define(['./_DataView', './_Map', './_Promise', './_Set', './_WeakMap', './_toSou
       (WeakMap && getTag(new WeakMap) != weakMapTag)) {
     getTag = function(value) {
       var result = objectToString.call(value),
-          Ctor = result == objectTag ? value.constructor : null,
-          ctorString = toSource(Ctor);
+          Ctor = result == objectTag ? value.constructor : undefined,
+          ctorString = Ctor ? toSource(Ctor) : undefined;
 
       if (ctorString) {
         switch (ctorString) {
diff --git a/_isFlattenable.js b/_isFlattenable.js
new file mode 100644
index 000000000..e04aeb6f0
--- /dev/null
+++ b/_isFlattenable.js
@@ -0,0 +1,15 @@
+define(['./isArguments', './isArray', './isArrayLikeObject'], function(isArguments, isArray, isArrayLikeObject) {
+
+  /**
+   * Checks if `value` is a flattenable `arguments` object or array.
+   *
+   * @private
+   * @param {*} value The value to check.
+   * @returns {boolean} Returns `true` if `value` is flattenable, else `false`.
+   */
+  function isFlattenable(value) {
+    return isArrayLikeObject(value) && (isArray(value) || isArguments(value));
+  }
+
+  return isFlattenable;
+});
diff --git a/_isFlattenableIteratee.js b/_isFlattenableIteratee.js
new file mode 100644
index 000000000..7390271f3
--- /dev/null
+++ b/_isFlattenableIteratee.js
@@ -0,0 +1,16 @@
+define(['./isArray', './isFunction'], function(isArray, isFunction) {
+
+  /**
+   * Checks if `value` is a flattenable array and not a `_.matchesProperty`
+   * iteratee shorthand.
+   *
+   * @private
+   * @param {*} value The value to check.
+   * @returns {boolean} Returns `true` if `value` is flattenable, else `false`.
+   */
+  function isFlattenableIteratee(value) {
+    return isArray(value) && !(value.length == 2 && !isFunction(value[0]));
+  }
+
+  return isFlattenableIteratee;
+});
diff --git a/_toSource.js b/_toSource.js
index a7c389282..1560ba83d 100644
--- a/_toSource.js
+++ b/_toSource.js
@@ -1,4 +1,4 @@
-define(['./isFunction', './toString'], function(isFunction, toString) {
+define([], function() {
 
   /** Used to resolve the decompiled source of functions. */
   var funcToString = Function.prototype.toString;
@@ -11,12 +11,15 @@ define(['./isFunction', './toString'], function(isFunction, toString) {
    * @returns {string} Returns the source code.
    */
   function toSource(func) {
-    if (isFunction(func)) {
+    if (func != null) {
       try {
         return funcToString.call(func);
       } catch (e) {}
+      try {
+        return (func + '');
+      } catch (e) {}
     }
-    return toString(func);
+    return '';
   }
 
   return toSource;
diff --git a/assignInWith.js b/assignInWith.js
index 7ad9d0c0d..0ff470621 100644
--- a/assignInWith.js
+++ b/assignInWith.js
@@ -3,7 +3,7 @@ define(['./_copyObjectWith', './_createAssigner', './keysIn'], function(copyObje
   /**
    * This method is like `_.assignIn` except that it accepts `customizer`
    * which is invoked to produce the assigned values. If `customizer` returns
-   * `undefined` assignment is handled by the method instead. The `customizer`
+   * `undefined`, assignment is handled by the method instead. The `customizer`
    * is invoked with five arguments: (objValue, srcValue, key, object, source).
    *
    * **Note:** This method mutates `object`.
diff --git a/assignWith.js b/assignWith.js
index 8cf2170a1..5cb9fa092 100644
--- a/assignWith.js
+++ b/assignWith.js
@@ -3,7 +3,7 @@ define(['./_copyObjectWith', './_createAssigner', './keys'], function(copyObject
   /**
    * This method is like `_.assign` except that it accepts `customizer`
    * which is invoked to produce the assigned values. If `customizer` returns
-   * `undefined` assignment is handled by the method instead. The `customizer`
+   * `undefined`, assignment is handled by the method instead. The `customizer`
    * is invoked with five arguments: (objValue, srcValue, key, object, source).
    *
    * **Note:** This method mutates `object`.
diff --git a/cloneWith.js b/cloneWith.js
index 512869e85..f84f1a35a 100644
--- a/cloneWith.js
+++ b/cloneWith.js
@@ -2,7 +2,7 @@ define(['./_baseClone'], function(baseClone) {
 
   /**
    * This method is like `_.clone` except that it accepts `customizer` which
-   * is invoked to produce the cloned value. If `customizer` returns `undefined`
+   * is invoked to produce the cloned value. If `customizer` returns `undefined`,
    * cloning is handled by the method instead. The `customizer` is invoked with
    * up to four arguments; (value [, index|key, object, stack]).
    *
diff --git a/create.js b/create.js
index bc2abec36..c51eeef74 100644
--- a/create.js
+++ b/create.js
@@ -2,7 +2,7 @@ define(['./_baseAssign', './_baseCreate'], function(baseAssign, baseCreate) {
 
   /**
    * Creates an object that inherits from the `prototype` object. If a
-   * `properties` object is given its own enumerable string keyed properties
+   * `properties` object is given, its own enumerable string keyed properties
    * are assigned to the created object.
    *
    * @static
diff --git a/debounce.js b/debounce.js
index f250113f5..3bafaeb82 100644
--- a/debounce.js
+++ b/debounce.js
@@ -24,7 +24,7 @@ define(['./isObject', './now', './toNumber'], function(isObject, now, toNumber)
    * on the trailing edge of the timeout only if the debounced function is
    * invoked more than once during the `wait` timeout.
    *
-   * See [David Corbacho's article](http://drupalmotion.com/article/debounce-and-throttle-visual-explanation)
+   * See [David Corbacho's article](https://css-tricks.com/debouncing-throttling-explained-examples/)
    * for details over the differences between `_.debounce` and `_.throttle`.
    *
    * @static
diff --git a/difference.js b/difference.js
index 0f9298fd7..90e09c7cb 100644
--- a/difference.js
+++ b/difference.js
@@ -20,7 +20,7 @@ define(['./_baseDifference', './_baseFlatten', './isArrayLikeObject', './rest'],
    */
   var difference = rest(function(array, values) {
     return isArrayLikeObject(array)
-      ? baseDifference(array, baseFlatten(values, 1, true))
+      ? baseDifference(array, baseFlatten(values, 1, isArrayLikeObject, true))
       : [];
   });
 
diff --git a/differenceBy.js b/differenceBy.js
index 96d8efab4..9b0e9f4d6 100644
--- a/differenceBy.js
+++ b/differenceBy.js
@@ -33,7 +33,7 @@ define(['./_baseDifference', './_baseFlatten', './_baseIteratee', './isArrayLike
       iteratee = undefined;
     }
     return isArrayLikeObject(array)
-      ? baseDifference(array, baseFlatten(values, 1, true), baseIteratee(iteratee))
+      ? baseDifference(array, baseFlatten(values, 1, isArrayLikeObject, true), baseIteratee(iteratee))
       : [];
   });
 
diff --git a/differenceWith.js b/differenceWith.js
index ba68aa3c0..6ce42902e 100644
--- a/differenceWith.js
+++ b/differenceWith.js
@@ -30,7 +30,7 @@ define(['./_baseDifference', './_baseFlatten', './isArrayLikeObject', './last',
       comparator = undefined;
     }
     return isArrayLikeObject(array)
-      ? baseDifference(array, baseFlatten(values, 1, true), undefined, comparator)
+      ? baseDifference(array, baseFlatten(values, 1, isArrayLikeObject, true), undefined, comparator)
       : [];
   });
 
diff --git a/get.js b/get.js
index cb3c64c73..18dd1cc43 100644
--- a/get.js
+++ b/get.js
@@ -5,7 +5,7 @@ define(['./_baseGet'], function(baseGet) {
 
   /**
    * Gets the value at `path` of `object`. If the resolved value is
-   * `undefined` the `defaultValue` is used in its place.
+   * `undefined`, the `defaultValue` is used in its place.
    *
    * @static
    * @memberOf _
diff --git a/groupBy.js b/groupBy.js
index a8b08256c..ea76ce3f2 100644
--- a/groupBy.js
+++ b/groupBy.js
@@ -8,9 +8,10 @@ define(['./_createAggregator'], function(createAggregator) {
 
   /**
    * Creates an object composed of keys generated from the results of running
-   * each element of `collection` thru `iteratee`. The corresponding value of
-   * each key is an array of elements responsible for generating the key. The
-   * iteratee is invoked with one argument: (value).
+   * each element of `collection` thru `iteratee`. The order of grouped values
+   * is determined by the order they occur in `collection`. The corresponding
+   * value of each key is an array of elements responsible for generating the
+   * key. The iteratee is invoked with one argument: (value).
    *
    * @static
    * @memberOf _
diff --git a/has.js b/has.js
index 5575cf8cf..7855e7253 100644
--- a/has.js
+++ b/has.js
@@ -12,16 +12,16 @@ define(['./_baseHas', './_hasPath'], function(baseHas, hasPath) {
    * @returns {boolean} Returns `true` if `path` exists, else `false`.
    * @example
    *
-   * var object = { 'a': { 'b': { 'c': 3 } } };
-   * var other = _.create({ 'a': _.create({ 'b': _.create({ 'c': 3 }) }) });
+   * var object = { 'a': { 'b': 2 } };
+   * var other = _.create({ 'a': _.create({ 'b': 2 }) });
    *
    * _.has(object, 'a');
    * // => true
    *
-   * _.has(object, 'a.b.c');
+   * _.has(object, 'a.b');
    * // => true
    *
-   * _.has(object, ['a', 'b', 'c']);
+   * _.has(object, ['a', 'b']);
    * // => true
    *
    * _.has(other, 'a');
diff --git a/hasIn.js b/hasIn.js
index 90b6952d6..b46ba2a2e 100644
--- a/hasIn.js
+++ b/hasIn.js
@@ -12,15 +12,15 @@ define(['./_baseHasIn', './_hasPath'], function(baseHasIn, hasPath) {
    * @returns {boolean} Returns `true` if `path` exists, else `false`.
    * @example
    *
-   * var object = _.create({ 'a': _.create({ 'b': _.create({ 'c': 3 }) }) });
+   * var object = _.create({ 'a': _.create({ 'b': 2 }) });
    *
    * _.hasIn(object, 'a');
    * // => true
    *
-   * _.hasIn(object, 'a.b.c');
+   * _.hasIn(object, 'a.b');
    * // => true
    *
-   * _.hasIn(object, ['a', 'b', 'c']);
+   * _.hasIn(object, ['a', 'b']);
    * // => true
    *
    * _.hasIn(object, 'b');
diff --git a/inRange.js b/inRange.js
index cb4ddf280..be6c625c2 100644
--- a/inRange.js
+++ b/inRange.js
@@ -5,7 +5,7 @@ define(['./_baseInRange', './toNumber'], function(baseInRange, toNumber) {
 
   /**
    * Checks if `n` is between `start` and up to but not including, `end`. If
-   * `end` is not specified it's set to `start` with `start` then set to `0`.
+   * `end` is not specified, it's set to `start` with `start` then set to `0`.
    * If `start` is greater than `end` the params are swapped to support
    * negative ranges.
    *
diff --git a/includes.js b/includes.js
index 2af31fbd8..4beac82e6 100644
--- a/includes.js
+++ b/includes.js
@@ -4,7 +4,7 @@ define(['./_baseIndexOf', './isArrayLike', './isString', './toInteger', './value
   var nativeMax = Math.max;
 
   /**
-   * Checks if `value` is in `collection`. If `collection` is a string it's
+   * Checks if `value` is in `collection`. If `collection` is a string, it's
    * checked for a substring of `value`, otherwise
    * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
    * is used for equality comparisons. If `fromIndex` is negative, it's used as
diff --git a/indexOf.js b/indexOf.js
index 349faf175..2da5031b9 100644
--- a/indexOf.js
+++ b/indexOf.js
@@ -6,8 +6,8 @@ define(['./_baseIndexOf', './toInteger'], function(baseIndexOf, toInteger) {
   /**
    * Gets the index at which the first occurrence of `value` is found in `array`
    * using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
-   * for equality comparisons. If `fromIndex` is negative, it's used as the offset
-   * from the end of `array`.
+   * for equality comparisons. If `fromIndex` is negative, it's used as the
+   * offset from the end of `array`.
    *
    * @static
    * @memberOf _
diff --git a/invokeMap.js b/invokeMap.js
index 69aecab21..5cc83c8f3 100644
--- a/invokeMap.js
+++ b/invokeMap.js
@@ -6,8 +6,8 @@ define(['./_apply', './_baseEach', './_baseInvoke', './isArrayLike', './_isKey',
   /**
    * 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's
-   * invoked for, and `this` bound to, each element in `collection`.
+   * are provided to each invoked method. If `methodName` is a function, it's
+   * invoked for and `this` bound to, each element in `collection`.
    *
    * @static
    * @memberOf _
diff --git a/isEqualWith.js b/isEqualWith.js
index 1e55e2f32..c4c3a07de 100644
--- a/isEqualWith.js
+++ b/isEqualWith.js
@@ -5,7 +5,7 @@ define(['./_baseIsEqual'], function(baseIsEqual) {
 
   /**
    * This method is like `_.isEqual` except that it accepts `customizer` which
-   * is invoked to compare values. If `customizer` returns `undefined` comparisons
+   * is invoked to compare values. If `customizer` returns `undefined`, comparisons
    * are handled by the method instead. The `customizer` is invoked with up to
    * six arguments: (objValue, othValue [, index|key, object, other, stack]).
    *
diff --git a/isMatchWith.js b/isMatchWith.js
index 8a9a6480e..48849f450 100644
--- a/isMatchWith.js
+++ b/isMatchWith.js
@@ -5,7 +5,7 @@ define(['./_baseIsMatch', './_getMatchData'], function(baseIsMatch, getMatchData
 
   /**
    * This method is like `_.isMatch` except that it accepts `customizer` which
-   * is invoked to compare values. If `customizer` returns `undefined` comparisons
+   * is invoked to compare values. If `customizer` returns `undefined`, comparisons
    * are handled by the method instead. The `customizer` is invoked with five
    * arguments: (objValue, srcValue, index|key, object, source).
    *
diff --git a/iteratee.js b/iteratee.js
index b3a8b3d26..1acae35b3 100644
--- a/iteratee.js
+++ b/iteratee.js
@@ -2,8 +2,8 @@ define(['./_baseClone', './_baseIteratee'], function(baseClone, baseIteratee) {
 
   /**
    * Creates a function that invokes `func` with the arguments of the created
-   * function. If `func` is a property name the created function returns the
-   * property value for a given element. If `func` is an array or object the
+   * function. If `func` is a property name, the created function returns the
+   * property value for a given element. If `func` is an array or object, the
    * created function returns `true` for elements that contain the equivalent
    * source properties, otherwise it returns `false`.
    *
diff --git a/main.js b/main.js
index 62f381b0c..faae1d357 100644
--- a/main.js
+++ b/main.js
@@ -1,6 +1,6 @@
 /**
  * @license
- * lodash 4.8.2 (Custom Build) <https://lodash.com/>
+ * lodash 4.9.0 (Custom Build) <https://lodash.com/>
  * Build: `lodash exports="amd" -d -o ./main.js`
  * Copyright jQuery Foundation and other contributors <https://jquery.org/>
  * Released under MIT license <https://lodash.com/license>
@@ -13,7 +13,7 @@
   var undefined;
 
   /** Used as the semantic version number. */
-  var VERSION = '4.8.2';
+  var VERSION = '4.9.0';
 
   /** Used as the size to enable large array optimizations. */
   var LARGE_ARRAY_SIZE = 200;
@@ -1488,9 +1488,9 @@
      * Shortcut fusion is an optimization to merge iteratee calls; this avoids
      * the creation of intermediate arrays and can greatly reduce the number of
      * iteratee executions. Sections of a chain sequence qualify for shortcut
-     * fusion if the section is applied to an array of at least two hundred
-     * elements and any iteratees accept only one argument. The heuristic for
-     * whether a section qualifies for shortcut fusion is subject to change.
+     * fusion if the section is applied to an array of at least `200` elements
+     * and any iteratees accept only one argument. The heuristic for whether a
+     * section qualifies for shortcut fusion is subject to change.
      *
      * Chaining is supported in custom builds as long as the `_#value` method is
      * directly or indirectly included in the build.
@@ -1812,7 +1812,7 @@
     /*------------------------------------------------------------------------*/
 
     /**
-     * Creates an hash object.
+     * Creates a hash object.
      *
      * @private
      * @constructor
@@ -2701,23 +2701,24 @@
      * @private
      * @param {Array} array The array to flatten.
      * @param {number} depth The maximum recursion depth.
-     * @param {boolean} [isStrict] Restrict flattening to arrays-like objects.
+     * @param {boolean} [predicate=isFlattenable] The function invoked per iteration.
+     * @param {boolean} [isStrict] Restrict to values that pass `predicate` checks.
      * @param {Array} [result=[]] The initial result value.
      * @returns {Array} Returns the new flattened array.
      */
-    function baseFlatten(array, depth, isStrict, result) {
-      result || (result = []);
-
+    function baseFlatten(array, depth, predicate, isStrict, result) {
       var index = -1,
           length = array.length;
 
+      predicate || (predicate = isFlattenable);
+      result || (result = []);
+
       while (++index < length) {
         var value = array[index];
-        if (depth > 0 && isArrayLikeObject(value) &&
-            (isStrict || isArray(value) || isArguments(value))) {
+        if (depth > 0 && predicate(value)) {
           if (depth > 1) {
             // Recursively flatten arrays (susceptible to call stack limits).
-            baseFlatten(value, depth - 1, isStrict, result);
+            baseFlatten(value, depth - 1, predicate, isStrict, result);
           } else {
             arrayPush(result, value);
           }
@@ -4609,7 +4610,7 @@
      */
     function createOver(arrayFunc) {
       return rest(function(iteratees) {
-        iteratees = arrayMap(baseFlatten(iteratees, 1), getIteratee());
+        iteratees = arrayMap(baseFlatten(iteratees, 1, isFlattenableIteratee), getIteratee());
         return rest(function(args) {
           var thisArg = this;
           return arrayFunc(iteratees, function(iteratee) {
@@ -5152,10 +5153,10 @@
     }
 
     /**
-     * Gets the appropriate "iteratee" function. If the `_.iteratee` method is
-     * customized this function returns the custom method, otherwise it returns
-     * `baseIteratee`. If arguments are provided, the chosen function is invoked
-     * with them and its result is returned.
+     * Gets the appropriate "iteratee" function. If `_.iteratee` is customized,
+     * this function returns the custom method, otherwise it returns `baseIteratee`.
+     * If arguments are provided, the chosen function is invoked with them and
+     * its result is returned.
      *
      * @private
      * @param {*} [value] The value to convert to an iteratee.
@@ -5291,8 +5292,8 @@
         (WeakMap && getTag(new WeakMap) != weakMapTag)) {
       getTag = function(value) {
         var result = objectToString.call(value),
-            Ctor = result == objectTag ? value.constructor : null,
-            ctorString = toSource(Ctor);
+            Ctor = result == objectTag ? value.constructor : undefined,
+            ctorString = Ctor ? toSource(Ctor) : undefined;
 
         if (ctorString) {
           switch (ctorString) {
@@ -5464,6 +5465,29 @@
       return null;
     }
 
+    /**
+     * Checks if `value` is a flattenable `arguments` object or array.
+     *
+     * @private
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is flattenable, else `false`.
+     */
+    function isFlattenable(value) {
+      return isArrayLikeObject(value) && (isArray(value) || isArguments(value));
+    }
+
+    /**
+     * Checks if `value` is a flattenable array and not a `_.matchesProperty`
+     * iteratee shorthand.
+     *
+     * @private
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is flattenable, else `false`.
+     */
+    function isFlattenableIteratee(value) {
+      return isArray(value) && !(value.length == 2 && !isFunction(value[0]));
+    }
+
     /**
      * Checks if the given arguments are from an iteratee call.
      *
@@ -5768,12 +5792,15 @@
      * @returns {string} Returns the source code.
      */
     function toSource(func) {
-      if (isFunction(func)) {
+      if (func != null) {
         try {
           return funcToString.call(func);
         } catch (e) {}
+        try {
+          return (func + '');
+        } catch (e) {}
       }
-      return toString(func);
+      return '';
     }
 
     /**
@@ -5923,7 +5950,7 @@
      */
     var difference = rest(function(array, values) {
       return isArrayLikeObject(array)
-        ? baseDifference(array, baseFlatten(values, 1, true))
+        ? baseDifference(array, baseFlatten(values, 1, isArrayLikeObject, true))
         : [];
     });
 
@@ -5957,7 +5984,7 @@
         iteratee = undefined;
       }
       return isArrayLikeObject(array)
-        ? baseDifference(array, baseFlatten(values, 1, true), getIteratee(iteratee))
+        ? baseDifference(array, baseFlatten(values, 1, isArrayLikeObject, true), getIteratee(iteratee))
         : [];
     });
 
@@ -5988,7 +6015,7 @@
         comparator = undefined;
       }
       return isArrayLikeObject(array)
-        ? baseDifference(array, baseFlatten(values, 1, true), undefined, comparator)
+        ? baseDifference(array, baseFlatten(values, 1, isArrayLikeObject, true), undefined, comparator)
         : [];
     });
 
@@ -6387,8 +6414,8 @@
     /**
      * Gets the index at which the first occurrence of `value` is found in `array`
      * using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
-     * for equality comparisons. If `fromIndex` is negative, it's used as the offset
-     * from the end of `array`.
+     * for equality comparisons. If `fromIndex` is negative, it's used as the
+     * offset from the end of `array`.
      *
      * @static
      * @memberOf _
@@ -7254,7 +7281,7 @@
      * // => [2, 1, 4]
      */
     var union = rest(function(arrays) {
-      return baseUniq(baseFlatten(arrays, 1, true));
+      return baseUniq(baseFlatten(arrays, 1, isArrayLikeObject, true));
     });
 
     /**
@@ -7285,7 +7312,7 @@
       if (isArrayLikeObject(iteratee)) {
         iteratee = undefined;
       }
-      return baseUniq(baseFlatten(arrays, 1, true), getIteratee(iteratee));
+      return baseUniq(baseFlatten(arrays, 1, isArrayLikeObject, true), getIteratee(iteratee));
     });
 
     /**
@@ -7313,7 +7340,7 @@
       if (isArrayLikeObject(comparator)) {
         comparator = undefined;
       }
-      return baseUniq(baseFlatten(arrays, 1, true), undefined, comparator);
+      return baseUniq(baseFlatten(arrays, 1, isArrayLikeObject, true), undefined, comparator);
     });
 
     /**
@@ -8326,9 +8353,10 @@
 
     /**
      * Creates an object composed of keys generated from the results of running
-     * each element of `collection` thru `iteratee`. The corresponding value of
-     * each key is an array of elements responsible for generating the key. The
-     * iteratee is invoked with one argument: (value).
+     * each element of `collection` thru `iteratee`. The order of grouped values
+     * is determined by the order they occur in `collection`. The corresponding
+     * value of each key is an array of elements responsible for generating the
+     * key. The iteratee is invoked with one argument: (value).
      *
      * @static
      * @memberOf _
@@ -8356,7 +8384,7 @@
     });
 
     /**
-     * Checks if `value` is in `collection`. If `collection` is a string it's
+     * Checks if `value` is in `collection`. If `collection` is a string, it's
      * checked for a substring of `value`, otherwise
      * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
      * is used for equality comparisons. If `fromIndex` is negative, it's used as
@@ -8401,8 +8429,8 @@
     /**
      * 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's
-     * invoked for, and `this` bound to, each element in `collection`.
+     * are provided to each invoked method. If `methodName` is a function, it's
+     * invoked for and `this` bound to, each element in `collection`.
      *
      * @static
      * @memberOf _
@@ -8603,7 +8631,7 @@
      * Reduces `collection` to a value which is the accumulated result of running
      * each element in `collection` thru `iteratee`, where each successive
      * invocation is supplied the return value of the previous. If `accumulator`
-     * is not given the first element of `collection` is used as the initial
+     * is not given, the first element of `collection` is used as the initial
      * value. The iteratee is invoked with four arguments:
      * (accumulator, value, index|key, collection).
      *
@@ -9246,7 +9274,7 @@
      * on the trailing edge of the timeout only if the debounced function is
      * invoked more than once during the `wait` timeout.
      *
-     * See [David Corbacho's article](http://drupalmotion.com/article/debounce-and-throttle-visual-explanation)
+     * See [David Corbacho's article](https://css-tricks.com/debouncing-throttling-explained-examples/)
      * for details over the differences between `_.debounce` and `_.throttle`.
      *
      * @static
@@ -9468,7 +9496,7 @@
 
     /**
      * Creates a function that memoizes the result of `func`. If `resolver` is
-     * provided it determines the cache key for storing the result based on the
+     * provided, it determines the cache key for storing the result based on the
      * arguments provided to the memoized function. By default, the first argument
      * provided to the memoized function is used as the map cache key. The `func`
      * is invoked with the `this` binding of the memoized function.
@@ -9617,8 +9645,7 @@
      * // => [100, 10]
      */
     var overArgs = rest(function(func, transforms) {
-      transforms = arrayMap(baseFlatten(transforms, 1), getIteratee());
-
+      transforms = arrayMap(baseFlatten(transforms, 1, isFlattenableIteratee), getIteratee());
       var funcsLength = transforms.length;
       return rest(function(args) {
         var index = -1,
@@ -9851,7 +9878,7 @@
      * invoked on the trailing edge of the timeout only if the throttled function
      * is invoked more than once during the `wait` timeout.
      *
-     * See [David Corbacho's article](http://drupalmotion.com/article/debounce-and-throttle-visual-explanation)
+     * See [David Corbacho's article](https://css-tricks.com/debouncing-throttling-explained-examples/)
      * for details over the differences between `_.throttle` and `_.debounce`.
      *
      * @static
@@ -10016,7 +10043,7 @@
 
     /**
      * This method is like `_.clone` except that it accepts `customizer` which
-     * is invoked to produce the cloned value. If `customizer` returns `undefined`
+     * is invoked to produce the cloned value. If `customizer` returns `undefined`,
      * cloning is handled by the method instead. The `customizer` is invoked with
      * up to four arguments; (value [, index|key, object, stack]).
      *
@@ -10495,7 +10522,7 @@
 
     /**
      * This method is like `_.isEqual` except that it accepts `customizer` which
-     * is invoked to compare values. If `customizer` returns `undefined` comparisons
+     * is invoked to compare values. If `customizer` returns `undefined`, comparisons
      * are handled by the method instead. The `customizer` is invoked with up to
      * six arguments: (objValue, othValue [, index|key, object, other, stack]).
      *
@@ -10788,7 +10815,7 @@
 
     /**
      * This method is like `_.isMatch` except that it accepts `customizer` which
-     * is invoked to compare values. If `customizer` returns `undefined` comparisons
+     * is invoked to compare values. If `customizer` returns `undefined`, comparisons
      * are handled by the method instead. The `customizer` is invoked with five
      * arguments: (objValue, srcValue, index|key, object, source).
      *
@@ -11599,7 +11626,7 @@
     /**
      * This method is like `_.assignIn` except that it accepts `customizer`
      * which is invoked to produce the assigned values. If `customizer` returns
-     * `undefined` assignment is handled by the method instead. The `customizer`
+     * `undefined`, assignment is handled by the method instead. The `customizer`
      * is invoked with five arguments: (objValue, srcValue, key, object, source).
      *
      * **Note:** This method mutates `object`.
@@ -11631,7 +11658,7 @@
     /**
      * This method is like `_.assign` except that it accepts `customizer`
      * which is invoked to produce the assigned values. If `customizer` returns
-     * `undefined` assignment is handled by the method instead. The `customizer`
+     * `undefined`, assignment is handled by the method instead. The `customizer`
      * is invoked with five arguments: (objValue, srcValue, key, object, source).
      *
      * **Note:** This method mutates `object`.
@@ -11686,7 +11713,7 @@
 
     /**
      * Creates an object that inherits from the `prototype` object. If a
-     * `properties` object is given its own enumerable string keyed properties
+     * `properties` object is given, its own enumerable string keyed properties
      * are assigned to the created object.
      *
      * @static
@@ -12030,7 +12057,7 @@
 
     /**
      * Gets the value at `path` of `object`. If the resolved value is
-     * `undefined` the `defaultValue` is used in its place.
+     * `undefined`, the `defaultValue` is used in its place.
      *
      * @static
      * @memberOf _
@@ -12070,16 +12097,16 @@
      * @returns {boolean} Returns `true` if `path` exists, else `false`.
      * @example
      *
-     * var object = { 'a': { 'b': { 'c': 3 } } };
-     * var other = _.create({ 'a': _.create({ 'b': _.create({ 'c': 3 }) }) });
+     * var object = { 'a': { 'b': 2 } };
+     * var other = _.create({ 'a': _.create({ 'b': 2 }) });
      *
      * _.has(object, 'a');
      * // => true
      *
-     * _.has(object, 'a.b.c');
+     * _.has(object, 'a.b');
      * // => true
      *
-     * _.has(object, ['a', 'b', 'c']);
+     * _.has(object, ['a', 'b']);
      * // => true
      *
      * _.has(other, 'a');
@@ -12101,15 +12128,15 @@
      * @returns {boolean} Returns `true` if `path` exists, else `false`.
      * @example
      *
-     * var object = _.create({ 'a': _.create({ 'b': _.create({ 'c': 3 }) }) });
+     * var object = _.create({ 'a': _.create({ 'b': 2 }) });
      *
      * _.hasIn(object, 'a');
      * // => true
      *
-     * _.hasIn(object, 'a.b.c');
+     * _.hasIn(object, 'a.b');
      * // => true
      *
-     * _.hasIn(object, ['a', 'b', 'c']);
+     * _.hasIn(object, ['a', 'b']);
      * // => true
      *
      * _.hasIn(object, 'b');
@@ -12394,7 +12421,7 @@
     /**
      * This method is like `_.merge` except that it accepts `customizer` which
      * is invoked to produce the merged values of the destination and source
-     * properties. If `customizer` returns `undefined` merging is handled by the
+     * properties. If `customizer` returns `undefined`, merging is handled by the
      * method instead. The `customizer` is invoked with seven arguments:
      * (objValue, srcValue, key, object, source, stack).
      *
@@ -12586,7 +12613,7 @@
     }
 
     /**
-     * Sets the value at `path` of `object`. If a portion of `path` doesn't exist
+     * Sets the value at `path` of `object`. If a portion of `path` doesn't exist,
      * it's created. Arrays are created for missing index properties while objects
      * are created for all other missing properties. Use `_.setWith` to customize
      * `path` creation.
@@ -12939,7 +12966,7 @@
 
     /**
      * Checks if `n` is between `start` and up to but not including, `end`. If
-     * `end` is not specified it's set to `start` with `start` then set to `0`.
+     * `end` is not specified, it's set to `start` with `start` then set to `0`.
      * If `start` is greater than `end` the params are swapped to support
      * negative ranges.
      *
@@ -13534,7 +13561,18 @@
      * // => ['a', 'b']
      */
     function split(string, separator, limit) {
-      return toString(string).split(separator, limit);
+      string = toString(string);
+      if (string && (
+            typeof separator == 'string' ||
+            (separator != null && !isRegExp(separator))
+          )) {
+        separator += '';
+        if (separator == '' && reHasComplexSymbol.test(string)) {
+          var strSymbols = stringToArray(string);
+          return limit === undefined ? strSymbols : strSymbols.slice(0, limit < 0 ? 0 : limit);
+        }
+      }
+      return string.split(separator, limit);
     }
 
     /**
@@ -13596,7 +13634,7 @@
      * in "interpolate" delimiters, HTML-escape interpolated data properties in
      * "escape" delimiters, and execute JavaScript in "evaluate" delimiters. Data
      * properties may be accessed as free variables in the template. If a setting
-     * object is given it takes precedence over `_.templateSettings` values.
+     * object is given, it takes precedence over `_.templateSettings` values.
      *
      * **Note:** In the development build `_.template` utilizes
      * [sourceURLs](http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/#toc-sourceurl)
@@ -14391,8 +14429,8 @@
 
     /**
      * Creates a function that invokes `func` with the arguments of the created
-     * function. If `func` is a property name the created function returns the
-     * property value for a given element. If `func` is an array or object the
+     * function. If `func` is a property name, the created function returns the
+     * property value for a given element. If `func` is an array or object, the
      * created function returns `true` for elements that contain the equivalent
      * source properties, otherwise it returns `false`.
      *
@@ -14505,14 +14543,14 @@
      * @example
      *
      * var objects = [
-     *   { 'a': { 'b': { 'c': _.constant(2) } } },
-     *   { 'a': { 'b': { 'c': _.constant(1) } } }
+     *   { 'a': { 'b': _.constant(2) } },
+     *   { 'a': { 'b': _.constant(1) } }
      * ];
      *
-     * _.map(objects, _.method('a.b.c'));
+     * _.map(objects, _.method('a.b'));
      * // => [2, 1]
      *
-     * _.map(objects, _.method(['a', 'b', 'c']));
+     * _.map(objects, _.method(['a', 'b']));
      * // => [2, 1]
      */
     var method = rest(function(path, args) {
@@ -14552,7 +14590,7 @@
 
     /**
      * Adds all own enumerable string keyed function properties of a source
-     * object to the destination object. If `object` is a function then methods
+     * object to the destination object. If `object` is a function, then methods
      * are added to its prototype as well.
      *
      * **Note:** Use `_.runInContext` to create a pristine `lodash` function to
@@ -14765,14 +14803,14 @@
      * @example
      *
      * var objects = [
-     *   { 'a': { 'b': { 'c': 2 } } },
-     *   { 'a': { 'b': { 'c': 1 } } }
+     *   { 'a': { 'b': 2 } },
+     *   { 'a': { 'b': 1 } }
      * ];
      *
-     * _.map(objects, _.property('a.b.c'));
+     * _.map(objects, _.property('a.b'));
      * // => [2, 1]
      *
-     * _.map(_.sortBy(objects, _.property(['a', 'b', 'c'])), 'a.b.c');
+     * _.map(_.sortBy(objects, _.property(['a', 'b'])), 'a.b');
      * // => [1, 2]
      */
     function property(path) {
@@ -14809,7 +14847,7 @@
     /**
      * Creates an array of numbers (positive and/or negative) progressing from
      * `start` up to, but not including, `end`. A step of `-1` is used if a negative
-     * `start` is specified without an `end` or `step`. If `end` is not specified
+     * `start` is specified without an `end` or `step`. If `end` is not specified,
      * it's set to `start` with `start` then set to `0`.
      *
      * **Note:** JavaScript follows the IEEE-754 standard for resolving
@@ -14956,7 +14994,7 @@
     }
 
     /**
-     * Generates a unique ID. If `prefix` is given the ID is appended to it.
+     * Generates a unique ID. If `prefix` is given, the ID is appended to it.
      *
      * @static
      * @since 0.1.0
@@ -15064,7 +15102,7 @@
     var floor = createRound('floor');
 
     /**
-     * Computes the maximum value of `array`. If `array` is empty or falsey
+     * Computes the maximum value of `array`. If `array` is empty or falsey,
      * `undefined` is returned.
      *
      * @static
@@ -15164,7 +15202,7 @@
     }
 
     /**
-     * Computes the minimum value of `array`. If `array` is empty or falsey
+     * Computes the minimum value of `array`. If `array` is empty or falsey,
      * `undefined` is returned.
      *
      * @static
diff --git a/max.js b/max.js
index 06c792c37..f0d7579db 100644
--- a/max.js
+++ b/max.js
@@ -4,7 +4,7 @@ define(['./_baseExtremum', './gt', './identity'], function(baseExtremum, gt, ide
   var undefined;
 
   /**
-   * Computes the maximum value of `array`. If `array` is empty or falsey
+   * Computes the maximum value of `array`. If `array` is empty or falsey,
    * `undefined` is returned.
    *
    * @static
diff --git a/memoize.js b/memoize.js
index b21a9757d..299354007 100644
--- a/memoize.js
+++ b/memoize.js
@@ -5,7 +5,7 @@ define(['./_MapCache'], function(MapCache) {
 
   /**
    * Creates a function that memoizes the result of `func`. If `resolver` is
-   * provided it determines the cache key for storing the result based on the
+   * provided, it determines the cache key for storing the result based on the
    * arguments provided to the memoized function. By default, the first argument
    * provided to the memoized function is used as the map cache key. The `func`
    * is invoked with the `this` binding of the memoized function.
diff --git a/mergeWith.js b/mergeWith.js
index df7b6a3d5..5c3470fd8 100644
--- a/mergeWith.js
+++ b/mergeWith.js
@@ -3,7 +3,7 @@ define(['./_baseMerge', './_createAssigner'], function(baseMerge, createAssigner
   /**
    * This method is like `_.merge` except that it accepts `customizer` which
    * is invoked to produce the merged values of the destination and source
-   * properties. If `customizer` returns `undefined` merging is handled by the
+   * properties. If `customizer` returns `undefined`, merging is handled by the
    * method instead. The `customizer` is invoked with seven arguments:
    * (objValue, srcValue, key, object, source, stack).
    *
diff --git a/method.js b/method.js
index 84a87e506..79bac64a9 100644
--- a/method.js
+++ b/method.js
@@ -14,14 +14,14 @@ define(['./_baseInvoke', './rest'], function(baseInvoke, rest) {
    * @example
    *
    * var objects = [
-   *   { 'a': { 'b': { 'c': _.constant(2) } } },
-   *   { 'a': { 'b': { 'c': _.constant(1) } } }
+   *   { 'a': { 'b': _.constant(2) } },
+   *   { 'a': { 'b': _.constant(1) } }
    * ];
    *
-   * _.map(objects, _.method('a.b.c'));
+   * _.map(objects, _.method('a.b'));
    * // => [2, 1]
    *
-   * _.map(objects, _.method(['a', 'b', 'c']));
+   * _.map(objects, _.method(['a', 'b']));
    * // => [2, 1]
    */
   var method = rest(function(path, args) {
diff --git a/min.js b/min.js
index 6f30e4cb4..f6722baed 100644
--- a/min.js
+++ b/min.js
@@ -4,7 +4,7 @@ define(['./_baseExtremum', './identity', './lt'], function(baseExtremum, identit
   var undefined;
 
   /**
-   * Computes the minimum value of `array`. If `array` is empty or falsey
+   * Computes the minimum value of `array`. If `array` is empty or falsey,
    * `undefined` is returned.
    *
    * @static
diff --git a/mixin.js b/mixin.js
index c1903aa91..7e54a7ff6 100644
--- a/mixin.js
+++ b/mixin.js
@@ -2,7 +2,7 @@ define(['./_arrayEach', './_arrayPush', './_baseFunctions', './_copyArray', './i
 
   /**
    * Adds all own enumerable string keyed function properties of a source
-   * object to the destination object. If `object` is a function then methods
+   * object to the destination object. If `object` is a function, then methods
    * are added to its prototype as well.
    *
    * **Note:** Use `_.runInContext` to create a pristine `lodash` function to
diff --git a/overArgs.js b/overArgs.js
index 308998de5..14f6e7d77 100644
--- a/overArgs.js
+++ b/overArgs.js
@@ -1,4 +1,4 @@
-define(['./_apply', './_arrayMap', './_baseFlatten', './_baseIteratee', './rest'], function(apply, arrayMap, baseFlatten, baseIteratee, rest) {
+define(['./_apply', './_arrayMap', './_baseFlatten', './_baseIteratee', './_isFlattenableIteratee', './rest'], function(apply, arrayMap, baseFlatten, baseIteratee, isFlattenableIteratee, rest) {
 
   /* Built-in method references for those with the same name as other `lodash` methods. */
   var nativeMin = Math.min;
@@ -36,8 +36,7 @@ define(['./_apply', './_arrayMap', './_baseFlatten', './_baseIteratee', './rest'
    * // => [100, 10]
    */
   var overArgs = rest(function(func, transforms) {
-    transforms = arrayMap(baseFlatten(transforms, 1), baseIteratee);
-
+    transforms = arrayMap(baseFlatten(transforms, 1, isFlattenableIteratee), baseIteratee);
     var funcsLength = transforms.length;
     return rest(function(args) {
       var index = -1,
diff --git a/package.json b/package.json
index 93c03682a..6d2c90ccd 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "lodash-amd",
-  "version": "4.8.2",
+  "version": "4.9.0",
   "description": "Lodash exported as AMD modules.",
   "homepage": "https://lodash.com/custom-builds",
   "license": "MIT",
diff --git a/property.js b/property.js
index 0e7f36744..7a433dad8 100644
--- a/property.js
+++ b/property.js
@@ -12,14 +12,14 @@ define(['./_baseProperty', './_basePropertyDeep', './_isKey'], function(baseProp
    * @example
    *
    * var objects = [
-   *   { 'a': { 'b': { 'c': 2 } } },
-   *   { 'a': { 'b': { 'c': 1 } } }
+   *   { 'a': { 'b': 2 } },
+   *   { 'a': { 'b': 1 } }
    * ];
    *
-   * _.map(objects, _.property('a.b.c'));
+   * _.map(objects, _.property('a.b'));
    * // => [2, 1]
    *
-   * _.map(_.sortBy(objects, _.property(['a', 'b', 'c'])), 'a.b.c');
+   * _.map(_.sortBy(objects, _.property(['a', 'b'])), 'a.b');
    * // => [1, 2]
    */
   function property(path) {
diff --git a/range.js b/range.js
index d2957bbcf..1637f2ea2 100644
--- a/range.js
+++ b/range.js
@@ -3,7 +3,7 @@ define(['./_createRange'], function(createRange) {
   /**
    * Creates an array of numbers (positive and/or negative) progressing from
    * `start` up to, but not including, `end`. A step of `-1` is used if a negative
-   * `start` is specified without an `end` or `step`. If `end` is not specified
+   * `start` is specified without an `end` or `step`. If `end` is not specified,
    * it's set to `start` with `start` then set to `0`.
    *
    * **Note:** JavaScript follows the IEEE-754 standard for resolving
diff --git a/reduce.js b/reduce.js
index 072a7c834..f4b00e35a 100644
--- a/reduce.js
+++ b/reduce.js
@@ -4,7 +4,7 @@ define(['./_arrayReduce', './_baseEach', './_baseIteratee', './_baseReduce', './
    * Reduces `collection` to a value which is the accumulated result of running
    * each element in `collection` thru `iteratee`, where each successive
    * invocation is supplied the return value of the previous. If `accumulator`
-   * is not given the first element of `collection` is used as the initial
+   * is not given, the first element of `collection` is used as the initial
    * value. The iteratee is invoked with four arguments:
    * (accumulator, value, index|key, collection).
    *
diff --git a/set.js b/set.js
index 35bc6dc3b..f1c1ca53f 100644
--- a/set.js
+++ b/set.js
@@ -1,7 +1,7 @@
 define(['./_baseSet'], function(baseSet) {
 
   /**
-   * Sets the value at `path` of `object`. If a portion of `path` doesn't exist
+   * Sets the value at `path` of `object`. If a portion of `path` doesn't exist,
    * it's created. Arrays are created for missing index properties while objects
    * are created for all other missing properties. Use `_.setWith` to customize
    * `path` creation.
diff --git a/split.js b/split.js
index d831fe06d..59cd3f172 100644
--- a/split.js
+++ b/split.js
@@ -1,4 +1,19 @@
-define(['./toString'], function(toString) {
+define(['./isRegExp', './_stringToArray', './toString'], function(isRegExp, stringToArray, toString) {
+
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
+  /** Used to compose unicode character classes. */
+  var rsAstralRange = '\\ud800-\\udfff',
+      rsComboMarksRange = '\\u0300-\\u036f\\ufe20-\\ufe23',
+      rsComboSymbolsRange = '\\u20d0-\\u20f0',
+      rsVarRange = '\\ufe0e\\ufe0f';
+
+  /** Used to compose unicode capture groups. */
+  var rsZWJ = '\\u200d';
+
+  /** Used to detect strings with [zero-width joiners or code points from the astral planes](http://eev.ee/blog/2015/09/12/dark-corners-of-unicode/). */
+  var reHasComplexSymbol = RegExp('[' + rsZWJ + rsAstralRange  + rsComboMarksRange + rsComboSymbolsRange + rsVarRange + ']');
 
   /**
    * Splits `string` by `separator`.
@@ -20,7 +35,18 @@ define(['./toString'], function(toString) {
    * // => ['a', 'b']
    */
   function split(string, separator, limit) {
-    return toString(string).split(separator, limit);
+    string = toString(string);
+    if (string && (
+          typeof separator == 'string' ||
+          (separator != null && !isRegExp(separator))
+        )) {
+      separator += '';
+      if (separator == '' && reHasComplexSymbol.test(string)) {
+        var strSymbols = stringToArray(string);
+        return limit === undefined ? strSymbols : strSymbols.slice(0, limit < 0 ? 0 : limit);
+      }
+    }
+    return string.split(separator, limit);
   }
 
   return split;
diff --git a/template.js b/template.js
index 65591f90c..0ca5d3bfd 100644
--- a/template.js
+++ b/template.js
@@ -25,7 +25,7 @@ define(['./_assignInDefaults', './assignInWith', './attempt', './_baseValues', '
    * in "interpolate" delimiters, HTML-escape interpolated data properties in
    * "escape" delimiters, and execute JavaScript in "evaluate" delimiters. Data
    * properties may be accessed as free variables in the template. If a setting
-   * object is given it takes precedence over `_.templateSettings` values.
+   * object is given, it takes precedence over `_.templateSettings` values.
    *
    * **Note:** In the development build `_.template` utilizes
    * [sourceURLs](http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/#toc-sourceurl)
diff --git a/throttle.js b/throttle.js
index a63e41b9f..d49e00016 100644
--- a/throttle.js
+++ b/throttle.js
@@ -17,7 +17,7 @@ define(['./debounce', './isObject'], function(debounce, isObject) {
    * invoked on the trailing edge of the timeout only if the throttled function
    * is invoked more than once during the `wait` timeout.
    *
-   * See [David Corbacho's article](http://drupalmotion.com/article/debounce-and-throttle-visual-explanation)
+   * See [David Corbacho's article](https://css-tricks.com/debouncing-throttling-explained-examples/)
    * for details over the differences between `_.throttle` and `_.debounce`.
    *
    * @static
diff --git a/union.js b/union.js
index db26f604b..bcaa37782 100644
--- a/union.js
+++ b/union.js
@@ -1,4 +1,4 @@
-define(['./_baseFlatten', './_baseUniq', './rest'], function(baseFlatten, baseUniq, rest) {
+define(['./_baseFlatten', './_baseUniq', './isArrayLikeObject', './rest'], function(baseFlatten, baseUniq, isArrayLikeObject, rest) {
 
   /**
    * Creates an array of unique values, in order, from all given arrays using
@@ -17,7 +17,7 @@ define(['./_baseFlatten', './_baseUniq', './rest'], function(baseFlatten, baseUn
    * // => [2, 1, 4]
    */
   var union = rest(function(arrays) {
-    return baseUniq(baseFlatten(arrays, 1, true));
+    return baseUniq(baseFlatten(arrays, 1, isArrayLikeObject, true));
   });
 
   return union;
diff --git a/unionBy.js b/unionBy.js
index 71eeafd29..180fad6b1 100644
--- a/unionBy.js
+++ b/unionBy.js
@@ -31,7 +31,7 @@ define(['./_baseFlatten', './_baseIteratee', './_baseUniq', './isArrayLikeObject
     if (isArrayLikeObject(iteratee)) {
       iteratee = undefined;
     }
-    return baseUniq(baseFlatten(arrays, 1, true), baseIteratee(iteratee));
+    return baseUniq(baseFlatten(arrays, 1, isArrayLikeObject, true), baseIteratee(iteratee));
   });
 
   return unionBy;
diff --git a/unionWith.js b/unionWith.js
index 76cf0e445..b40c85577 100644
--- a/unionWith.js
+++ b/unionWith.js
@@ -28,7 +28,7 @@ define(['./_baseFlatten', './_baseUniq', './isArrayLikeObject', './last', './res
     if (isArrayLikeObject(comparator)) {
       comparator = undefined;
     }
-    return baseUniq(baseFlatten(arrays, 1, true), undefined, comparator);
+    return baseUniq(baseFlatten(arrays, 1, isArrayLikeObject, true), undefined, comparator);
   });
 
   return unionWith;
diff --git a/uniqueId.js b/uniqueId.js
index e26abf6b9..c2950c739 100644
--- a/uniqueId.js
+++ b/uniqueId.js
@@ -4,7 +4,7 @@ define(['./toString'], function(toString) {
   var idCounter = 0;
 
   /**
-   * Generates a unique ID. If `prefix` is given the ID is appended to it.
+   * Generates a unique ID. If `prefix` is given, the ID is appended to it.
    *
    * @static
    * @since 0.1.0
diff --git a/wrapperLodash.js b/wrapperLodash.js
index e4dda7814..31b3e9585 100644
--- a/wrapperLodash.js
+++ b/wrapperLodash.js
@@ -24,9 +24,9 @@ define(['./_LazyWrapper', './_LodashWrapper', './_baseLodash', './isArray', './i
    * Shortcut fusion is an optimization to merge iteratee calls; this avoids
    * the creation of intermediate arrays and can greatly reduce the number of
    * iteratee executions. Sections of a chain sequence qualify for shortcut
-   * fusion if the section is applied to an array of at least two hundred
-   * elements and any iteratees accept only one argument. The heuristic for
-   * whether a section qualifies for shortcut fusion is subject to change.
+   * fusion if the section is applied to an array of at least `200` elements
+   * and any iteratees accept only one argument. The heuristic for whether a
+   * section qualifies for shortcut fusion is subject to change.
    *
    * Chaining is supported in custom builds as long as the `_#value` method is
    * directly or indirectly included in the build.