diff --git a/README.md b/README.md
index 31c1217ac..e8e2de24b 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-# lodash-es v4.9.0
+# lodash-es v4.10.0
 
 The [Lodash](https://lodash.com/) library exported as [ES](http://www.ecma-international.org/ecma-262/6.0/) modules.
 
@@ -7,4 +7,4 @@ Generated using [lodash-cli](https://www.npmjs.com/package/lodash-cli):
 $ lodash modularize exports=es -o ./
 ```
 
-See the [package source](https://github.com/lodash/lodash/tree/4.9.0-es) for more details.
+See the [package source](https://github.com/lodash/lodash/tree/4.10.0-es) for more details.
diff --git a/_baseFor.js b/_baseFor.js
index 7dbcfb36f..64b462b27 100644
--- a/_baseFor.js
+++ b/_baseFor.js
@@ -2,7 +2,7 @@ import createBaseFor from './_createBaseFor';
 
 /**
  * The base implementation of `baseForOwn` which iterates over `object`
- * properties returned by `keysFunc` invoking `iteratee` for each property.
+ * properties returned by `keysFunc` and invokes `iteratee` for each property.
  * Iteratee functions may exit iteration early by explicitly returning `false`.
  *
  * @private
diff --git a/_baseGet.js b/_baseGet.js
index 0b7194ff6..a34892e8d 100644
--- a/_baseGet.js
+++ b/_baseGet.js
@@ -1,4 +1,4 @@
-import baseCastPath from './_baseCastPath';
+import castPath from './_castPath';
 import isKey from './_isKey';
 
 /**
@@ -10,7 +10,7 @@ import isKey from './_isKey';
  * @returns {*} Returns the resolved value.
  */
 function baseGet(object, path) {
-  path = isKey(path, object) ? [path] : baseCastPath(path);
+  path = isKey(path, object) ? [path] : castPath(path);
 
   var index = 0,
       length = path.length;
diff --git a/_baseInvoke.js b/_baseInvoke.js
index 8ba20a268..a38b84a83 100644
--- a/_baseInvoke.js
+++ b/_baseInvoke.js
@@ -1,5 +1,5 @@
 import apply from './_apply';
-import baseCastPath from './_baseCastPath';
+import castPath from './_castPath';
 import isKey from './_isKey';
 import last from './last';
 import parent from './_parent';
@@ -16,7 +16,7 @@ import parent from './_parent';
  */
 function baseInvoke(object, path, args) {
   if (!isKey(path, object)) {
-    path = baseCastPath(path);
+    path = castPath(path);
     object = parent(object, path);
     path = last(path);
   }
diff --git a/_basePullAt.js b/_basePullAt.js
index 470afcbcc..ecf27ccb3 100644
--- a/_basePullAt.js
+++ b/_basePullAt.js
@@ -1,4 +1,4 @@
-import baseCastPath from './_baseCastPath';
+import castPath from './_castPath';
 import isIndex from './_isIndex';
 import isKey from './_isKey';
 import last from './last';
@@ -31,7 +31,7 @@ function basePullAt(array, indexes) {
         splice.call(array, index, 1);
       }
       else if (!isKey(index, array)) {
-        var path = baseCastPath(index),
+        var path = castPath(index),
             object = parent(array, path);
 
         if (object != null) {
diff --git a/_baseSet.js b/_baseSet.js
index 6e96a08ea..c08d7ac03 100644
--- a/_baseSet.js
+++ b/_baseSet.js
@@ -1,5 +1,5 @@
 import assignValue from './_assignValue';
-import baseCastPath from './_baseCastPath';
+import castPath from './_castPath';
 import isIndex from './_isIndex';
 import isKey from './_isKey';
 import isObject from './isObject';
@@ -15,7 +15,7 @@ import isObject from './isObject';
  * @returns {Object} Returns `object`.
  */
 function baseSet(object, path, value, customizer) {
-  path = isKey(path, object) ? [path] : baseCastPath(path);
+  path = isKey(path, object) ? [path] : castPath(path);
 
   var index = -1,
       length = path.length,
diff --git a/_baseUnset.js b/_baseUnset.js
index 7b937db9a..8a35e22f6 100644
--- a/_baseUnset.js
+++ b/_baseUnset.js
@@ -1,4 +1,4 @@
-import baseCastPath from './_baseCastPath';
+import castPath from './_castPath';
 import has from './has';
 import isKey from './_isKey';
 import last from './last';
@@ -13,7 +13,7 @@ import parent from './_parent';
  * @returns {boolean} Returns `true` if the property is deleted, else `false`.
  */
 function baseUnset(object, path) {
-  path = isKey(path, object) ? [path] : baseCastPath(path);
+  path = isKey(path, object) ? [path] : castPath(path);
   object = parent(object, path);
   var key = last(path);
   return (object != null && has(object, key)) ? delete object[key] : true;
diff --git a/_baseCastArrayLikeObject.js b/_castArrayLikeObject.js
similarity index 78%
rename from _baseCastArrayLikeObject.js
rename to _castArrayLikeObject.js
index 5bf6e11a1..ddea66adf 100644
--- a/_baseCastArrayLikeObject.js
+++ b/_castArrayLikeObject.js
@@ -7,8 +7,8 @@ import isArrayLikeObject from './isArrayLikeObject';
  * @param {*} value The value to inspect.
  * @returns {Array|Object} Returns the cast array-like object.
  */
-function baseCastArrayLikeObject(value) {
+function castArrayLikeObject(value) {
   return isArrayLikeObject(value) ? value : [];
 }
 
-export default baseCastArrayLikeObject;
+export default castArrayLikeObject;
diff --git a/_baseCastFunction.js b/_castFunction.js
similarity index 79%
rename from _baseCastFunction.js
rename to _castFunction.js
index 169d6c3aa..f5ac5d351 100644
--- a/_baseCastFunction.js
+++ b/_castFunction.js
@@ -7,8 +7,8 @@ import identity from './identity';
  * @param {*} value The value to inspect.
  * @returns {Function} Returns cast function.
  */
-function baseCastFunction(value) {
+function castFunction(value) {
   return typeof value == 'function' ? value : identity;
 }
 
-export default baseCastFunction;
+export default castFunction;
diff --git a/_baseCastPath.js b/_castPath.js
similarity index 83%
rename from _baseCastPath.js
rename to _castPath.js
index 41c7ecdd6..ffaf2b6c1 100644
--- a/_baseCastPath.js
+++ b/_castPath.js
@@ -8,8 +8,8 @@ import stringToPath from './_stringToPath';
  * @param {*} value The value to inspect.
  * @returns {Array} Returns the cast property path array.
  */
-function baseCastPath(value) {
+function castPath(value) {
   return isArray(value) ? value : stringToPath(value);
 }
 
-export default baseCastPath;
+export default castPath;
diff --git a/_castSlice.js b/_castSlice.js
new file mode 100644
index 000000000..4d8a7f52b
--- /dev/null
+++ b/_castSlice.js
@@ -0,0 +1,18 @@
+import baseSlice from './_baseSlice';
+
+/**
+ * Casts `array` to a slice if it's needed.
+ *
+ * @private
+ * @param {Array} array The array to inspect.
+ * @param {number} start The start position.
+ * @param {number} [end=array.length] The end position.
+ * @returns {Array} Returns the cast slice.
+ */
+function castSlice(array, start, end) {
+  var length = array.length;
+  end = end === undefined ? length : end;
+  return (!start && end >= length) ? array : baseSlice(array, start, end);
+}
+
+export default castSlice;
diff --git a/_createCaseFirst.js b/_createCaseFirst.js
index 69684d3b8..35279b667 100644
--- a/_createCaseFirst.js
+++ b/_createCaseFirst.js
@@ -1,18 +1,8 @@
+import castSlice from './_castSlice';
+import reHasComplexSymbol from './_reHasComplexSymbol';
 import stringToArray from './_stringToArray';
 import toString from './toString';
 
-/** 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 + ']');
-
 /**
  * Creates a function like `_.lowerFirst`.
  *
@@ -28,8 +18,13 @@ function createCaseFirst(methodName) {
       ? stringToArray(string)
       : undefined;
 
-    var chr = strSymbols ? strSymbols[0] : string.charAt(0),
-        trailing = strSymbols ? strSymbols.slice(1).join('') : string.slice(1);
+    var chr = strSymbols
+      ? strSymbols[0]
+      : string.charAt(0);
+
+    var trailing = strSymbols
+      ? castSlice(strSymbols, 1).join('')
+      : string.slice(1);
 
     return chr[methodName]() + trailing;
   };
diff --git a/_createPadding.js b/_createPadding.js
index 29d5fd138..acc7dba42 100644
--- a/_createPadding.js
+++ b/_createPadding.js
@@ -1,19 +1,9 @@
 import baseRepeat from './_baseRepeat';
+import castSlice from './_castSlice';
+import reHasComplexSymbol from './_reHasComplexSymbol';
 import stringSize from './_stringSize';
 import stringToArray from './_stringToArray';
 
-/** 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 + ']');
-
 /* Built-in method references for those with the same name as other `lodash` methods. */
 var nativeCeil = Math.ceil;
 
@@ -35,7 +25,7 @@ function createPadding(length, chars) {
   }
   var result = baseRepeat(chars, nativeCeil(length / stringSize(chars)));
   return reHasComplexSymbol.test(chars)
-    ? stringToArray(result).slice(0, length).join('')
+    ? castSlice(stringToArray(result), 0, length).join('')
     : result.slice(0, length);
 }
 
diff --git a/_hasPath.js b/_hasPath.js
index 901750cbc..74c454216 100644
--- a/_hasPath.js
+++ b/_hasPath.js
@@ -1,4 +1,4 @@
-import baseCastPath from './_baseCastPath';
+import castPath from './_castPath';
 import isArguments from './isArguments';
 import isArray from './isArray';
 import isIndex from './_isIndex';
@@ -16,7 +16,7 @@ import isString from './isString';
  * @returns {boolean} Returns `true` if `path` exists, else `false`.
  */
 function hasPath(object, path, hasFunc) {
-  path = isKey(path, object) ? [path] : baseCastPath(path);
+  path = isKey(path, object) ? [path] : castPath(path);
 
   var result,
       index = -1,
diff --git a/_reHasComplexSymbol.js b/_reHasComplexSymbol.js
new file mode 100644
index 000000000..fff4f9cbb
--- /dev/null
+++ b/_reHasComplexSymbol.js
@@ -0,0 +1,13 @@
+/** 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 + ']');
+
+export default reHasComplexSymbol;
diff --git a/_stringSize.js b/_stringSize.js
index 82337db1a..c85c6cbcb 100644
--- a/_stringSize.js
+++ b/_stringSize.js
@@ -1,3 +1,5 @@
+import reHasComplexSymbol from './_reHasComplexSymbol';
+
 /** Used to compose unicode character classes. */
 var rsAstralRange = '\\ud800-\\udfff',
     rsComboMarksRange = '\\u0300-\\u036f\\ufe20-\\ufe23',
@@ -24,9 +26,6 @@ var reOptMod = rsModifier + '?',
 /** Used to match [string symbols](https://mathiasbynens.be/notes/javascript-unicode). */
 var reComplexSymbol = RegExp(rsFitz + '(?=' + rsFitz + ')|' + rsSymbol + rsSeq, 'g');
 
-/** Used to detect strings with [zero-width joiners or code points from the astral planes](http://eev.ee/blog/2015/09/12/dark-corners-of-unicode/). */
-var reHasComplexSymbol = RegExp('[' + rsZWJ + rsAstralRange  + rsComboMarksRange + rsComboSymbolsRange + rsVarRange + ']');
-
 /**
  * Gets the number of symbols in `string`.
  *
diff --git a/_baseCastKey.js b/_toKey.js
similarity index 51%
rename from _baseCastKey.js
rename to _toKey.js
index cd2d475c9..4ce40d7b4 100644
--- a/_baseCastKey.js
+++ b/_toKey.js
@@ -1,14 +1,14 @@
 import isSymbol from './isSymbol';
 
 /**
- * Casts `value` to a string if it's not a string or symbol.
+ * Converts `value` to a string key if it's not a string or symbol.
  *
  * @private
  * @param {*} value The value to inspect.
- * @returns {string|symbol} Returns the cast key.
+ * @returns {string|symbol} Returns the key.
  */
-function baseCastKey(key) {
+function toKey(key) {
   return (typeof key == 'string' || isSymbol(key)) ? key : (key + '');
 }
 
-export default baseCastKey;
+export default toKey;
diff --git a/at.js b/at.js
index 74b5eeb9e..f0ed13489 100644
--- a/at.js
+++ b/at.js
@@ -10,8 +10,7 @@ import rest from './rest';
  * @since 1.0.0
  * @category Object
  * @param {Object} object The object to iterate over.
- * @param {...(string|string[])} [paths] The property paths of elements to pick,
- *  specified individually or in arrays.
+ * @param {...(string|string[])} [paths] The property paths of elements to pick.
  * @returns {Array} Returns the new array of picked elements.
  * @example
  *
diff --git a/bindAll.js b/bindAll.js
index 31478b7e9..b9dec1a18 100644
--- a/bindAll.js
+++ b/bindAll.js
@@ -14,8 +14,7 @@ import rest from './rest';
  * @memberOf _
  * @category Util
  * @param {Object} object The object to bind and assign the bound methods to.
- * @param {...(string|string[])} methodNames The object method names to bind,
- *  specified individually or in arrays.
+ * @param {...(string|string[])} methodNames The object method names to bind.
  * @returns {Object} Returns `object`.
  * @example
  *
diff --git a/cond.js b/cond.js
index 5c560ab44..eea509455 100644
--- a/cond.js
+++ b/cond.js
@@ -7,7 +7,7 @@ import rest from './rest';
 var FUNC_ERROR_TEXT = 'Expected a function';
 
 /**
- * Creates a function that iterates over `pairs` invoking the corresponding
+ * Creates a function that iterates over `pairs` and invokes the corresponding
  * function of the first predicate to return truthy. The predicate-function
  * pairs are invoked with the `this` binding and arguments of the created
  * function.
diff --git a/debounce.js b/debounce.js
index f13119b66..eaeacd277 100644
--- a/debounce.js
+++ b/debounce.js
@@ -169,6 +169,9 @@ function debounce(func, wait, options) {
       timerId = setTimeout(timerExpired, wait);
       return invokeFunc(lastCallTime);
     }
+    if (timerId === undefined) {
+      timerId = setTimeout(timerExpired, wait);
+    }
     return result;
   }
   debounced.cancel = cancel;
diff --git a/forEach.js b/forEach.js
index 8ac8b6cf7..1ecb92922 100644
--- a/forEach.js
+++ b/forEach.js
@@ -4,7 +4,7 @@ import baseIteratee from './_baseIteratee';
 import isArray from './isArray';
 
 /**
- * Iterates over elements of `collection` invoking `iteratee` for each element.
+ * Iterates over elements of `collection` and invokes `iteratee` for each element.
  * The iteratee is invoked with three arguments: (value, index|key, collection).
  * Iteratee functions may exit iteration early by explicitly returning `false`.
  *
diff --git a/forIn.js b/forIn.js
index cc773b166..30945a53a 100644
--- a/forIn.js
+++ b/forIn.js
@@ -4,9 +4,9 @@ import keysIn from './keysIn';
 
 /**
  * Iterates over own and inherited enumerable string keyed properties of an
- * object invoking `iteratee` for each property. The iteratee is invoked with
- * three arguments: (value, key, object). Iteratee functions may exit iteration
- * early by explicitly returning `false`.
+ * object and invokes `iteratee` for each property. The iteratee is invoked
+ * with three arguments: (value, key, object). Iteratee functions may exit
+ * iteration early by explicitly returning `false`.
  *
  * @static
  * @memberOf _
diff --git a/forOwn.js b/forOwn.js
index acf1f4f53..f9631a6fc 100644
--- a/forOwn.js
+++ b/forOwn.js
@@ -2,10 +2,10 @@ import baseForOwn from './_baseForOwn';
 import baseIteratee from './_baseIteratee';
 
 /**
- * Iterates over own enumerable string keyed properties of an object invoking
- * `iteratee` for each property. The iteratee is invoked with three arguments:
- * (value, key, object). Iteratee functions may exit iteration early by
- * explicitly returning `false`.
+ * Iterates over own enumerable string keyed properties of an object and
+ * invokes `iteratee` for each property. The iteratee is invoked with three
+ * arguments: (value, key, object). Iteratee functions may exit iteration
+ * early by explicitly returning `false`.
  *
  * @static
  * @memberOf _
diff --git a/intersection.js b/intersection.js
index 2e5f6b07a..ab7f50f16 100644
--- a/intersection.js
+++ b/intersection.js
@@ -1,6 +1,6 @@
 import arrayMap from './_arrayMap';
-import baseCastArrayLikeObject from './_baseCastArrayLikeObject';
 import baseIntersection from './_baseIntersection';
+import castArrayLikeObject from './_castArrayLikeObject';
 import rest from './rest';
 
 /**
@@ -21,7 +21,7 @@ import rest from './rest';
  * // => [2]
  */
 var intersection = rest(function(arrays) {
-  var mapped = arrayMap(arrays, baseCastArrayLikeObject);
+  var mapped = arrayMap(arrays, castArrayLikeObject);
   return (mapped.length && mapped[0] === arrays[0])
     ? baseIntersection(mapped)
     : [];
diff --git a/intersectionBy.js b/intersectionBy.js
index 9a298fae4..f6e8bbb7c 100644
--- a/intersectionBy.js
+++ b/intersectionBy.js
@@ -1,7 +1,7 @@
 import arrayMap from './_arrayMap';
-import baseCastArrayLikeObject from './_baseCastArrayLikeObject';
 import baseIntersection from './_baseIntersection';
 import baseIteratee from './_baseIteratee';
+import castArrayLikeObject from './_castArrayLikeObject';
 import last from './last';
 import rest from './rest';
 
@@ -30,7 +30,7 @@ import rest from './rest';
  */
 var intersectionBy = rest(function(arrays) {
   var iteratee = last(arrays),
-      mapped = arrayMap(arrays, baseCastArrayLikeObject);
+      mapped = arrayMap(arrays, castArrayLikeObject);
 
   if (iteratee === last(mapped)) {
     iteratee = undefined;
diff --git a/intersectionWith.js b/intersectionWith.js
index d0543e8b5..d4fa027e5 100644
--- a/intersectionWith.js
+++ b/intersectionWith.js
@@ -1,6 +1,6 @@
 import arrayMap from './_arrayMap';
-import baseCastArrayLikeObject from './_baseCastArrayLikeObject';
 import baseIntersection from './_baseIntersection';
+import castArrayLikeObject from './_castArrayLikeObject';
 import last from './last';
 import rest from './rest';
 
@@ -27,7 +27,7 @@ import rest from './rest';
  */
 var intersectionWith = rest(function(arrays) {
   var comparator = last(arrays),
-      mapped = arrayMap(arrays, baseCastArrayLikeObject);
+      mapped = arrayMap(arrays, castArrayLikeObject);
 
   if (comparator === last(mapped)) {
     comparator = undefined;
diff --git a/lodash.default.js b/lodash.default.js
index 903a4eeab..604e265e0 100644
--- a/lodash.default.js
+++ b/lodash.default.js
@@ -1,6 +1,6 @@
 /**
  * @license
- * lodash 4.9.0 (Custom Build) <https://lodash.com/>
+ * lodash 4.10.0 (Custom Build) <https://lodash.com/>
  * Build: `lodash modularize exports="es" -o ./`
  * Copyright jQuery Foundation and other contributors <https://jquery.org/>
  * Released under MIT license <https://lodash.com/license>
@@ -44,7 +44,7 @@ import toInteger from './toInteger';
 import lodash from './wrapperLodash';
 
 /** Used as the semantic version number. */
-var VERSION = '4.9.0';
+var VERSION = '4.10.0';
 
 /** Used to compose bitmasks for wrapper metadata. */
 var BIND_KEY_FLAG = 2;
diff --git a/lodash.js b/lodash.js
index 58564153d..618aa60ab 100644
--- a/lodash.js
+++ b/lodash.js
@@ -1,6 +1,6 @@
 /**
  * @license
- * lodash 4.9.0 (Custom Build) <https://lodash.com/>
+ * lodash 4.10.0 (Custom Build) <https://lodash.com/>
  * Build: `lodash modularize exports="es" -o ./`
  * Copyright jQuery Foundation and other contributors <https://jquery.org/>
  * Released under MIT license <https://lodash.com/license>
diff --git a/map.js b/map.js
index 9fb895872..888dc851f 100644
--- a/map.js
+++ b/map.js
@@ -14,8 +14,8 @@ import isArray from './isArray';
  * The guarded methods are:
  * `ary`, `chunk`, `curry`, `curryRight`, `drop`, `dropRight`, `every`,
  * `fill`, `invert`, `parseInt`, `random`, `range`, `rangeRight`, `repeat`,
- * `sampleSize`, `slice`, `some`, `sortBy`, `take`, `takeRight`, `template`,
- * `trim`, `trimEnd`, `trimStart`, and `words`
+ * `sampleSize`, `slice`, `some`, `sortBy`, `split`, `take`, `takeRight`,
+ * `template`, `trim`, `trimEnd`, `trimStart`, and `words`
  *
  * @static
  * @memberOf _
diff --git a/omit.js b/omit.js
index ebcef2d53..3eeb7ca89 100644
--- a/omit.js
+++ b/omit.js
@@ -1,10 +1,10 @@
 import arrayMap from './_arrayMap';
-import baseCastKey from './_baseCastKey';
 import baseDifference from './_baseDifference';
 import baseFlatten from './_baseFlatten';
 import basePick from './_basePick';
 import getAllKeysIn from './_getAllKeysIn';
 import rest from './rest';
+import toKey from './_toKey';
 
 /**
  * The opposite of `_.pick`; this method creates an object composed of the
@@ -16,8 +16,7 @@ import rest from './rest';
  * @memberOf _
  * @category Object
  * @param {Object} object The source object.
- * @param {...(string|string[])} [props] The property identifiers to omit,
- *  specified individually or in arrays.
+ * @param {...(string|string[])} [props] The property identifiers to omit.
  * @returns {Object} Returns the new object.
  * @example
  *
@@ -30,7 +29,7 @@ var omit = rest(function(object, props) {
   if (object == null) {
     return {};
   }
-  props = arrayMap(baseFlatten(props, 1), baseCastKey);
+  props = arrayMap(baseFlatten(props, 1), toKey);
   return basePick(object, baseDifference(getAllKeysIn(object), props));
 });
 
diff --git a/over.js b/over.js
index f08e5db61..1d49032a1 100644
--- a/over.js
+++ b/over.js
@@ -9,7 +9,8 @@ import createOver from './_createOver';
  * @memberOf _
  * @since 4.0.0
  * @category Util
- * @param {...(Function|Function[])} iteratees The iteratees to invoke.
+ * @param {...(Array|Array[]|Function|Function[]|Object|Object[]|string|string[])}
+ *  [iteratees=[_.identity]] The iteratees to invoke.
  * @returns {Function} Returns the new function.
  * @example
  *
diff --git a/overArgs.js b/overArgs.js
index 4e9e24ced..1e33d0279 100644
--- a/overArgs.js
+++ b/overArgs.js
@@ -17,8 +17,8 @@ var nativeMin = Math.min;
  * @memberOf _
  * @category Function
  * @param {Function} func The function to wrap.
- * @param {...(Function|Function[])} [transforms] The functions to transform.
- * arguments, specified individually or in arrays.
+ * @param {...(Array|Array[]|Function|Function[]|Object|Object[]|string|string[])}
+ *  [transforms[_.identity]] The functions to transform.
  * @returns {Function} Returns the new function.
  * @example
  *
diff --git a/overEvery.js b/overEvery.js
index 335503d1b..c3fd2b615 100644
--- a/overEvery.js
+++ b/overEvery.js
@@ -9,7 +9,8 @@ import createOver from './_createOver';
  * @memberOf _
  * @since 4.0.0
  * @category Util
- * @param {...(Function|Function[])} predicates The predicates to check.
+ * @param {...(Array|Array[]|Function|Function[]|Object|Object[]|string|string[])}
+ *  [predicates=[_.identity]] The predicates to check.
  * @returns {Function} Returns the new function.
  * @example
  *
diff --git a/overSome.js b/overSome.js
index 9c8021f91..70aab0b8a 100644
--- a/overSome.js
+++ b/overSome.js
@@ -9,7 +9,8 @@ import createOver from './_createOver';
  * @memberOf _
  * @since 4.0.0
  * @category Util
- * @param {...(Function|Function[])} predicates The predicates to check.
+ * @param {...(Array|Array[]|Function|Function[]|Object|Object[]|string|string[])}
+ *  [predicates=[_.identity]] The predicates to check.
  * @returns {Function} Returns the new function.
  * @example
  *
diff --git a/package.json b/package.json
index 927bb673d..95f3bf0e7 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "lodash-es",
-  "version": "4.9.0",
+  "version": "4.10.0",
   "description": "Lodash exported as ES modules.",
   "homepage": "https://lodash.com/custom-builds",
   "license": "MIT",
diff --git a/pick.js b/pick.js
index 0e1daa36c..fb587cc51 100644
--- a/pick.js
+++ b/pick.js
@@ -10,8 +10,7 @@ import rest from './rest';
  * @memberOf _
  * @category Object
  * @param {Object} object The source object.
- * @param {...(string|string[])} [props] The property identifiers to pick,
- *  specified individually or in arrays.
+ * @param {...(string|string[])} [props] The property identifiers to pick.
  * @returns {Object} Returns the new object.
  * @example
  *
diff --git a/pullAt.js b/pullAt.js
index 2f96df516..7f22bca73 100644
--- a/pullAt.js
+++ b/pullAt.js
@@ -16,8 +16,7 @@ import rest from './rest';
  * @since 3.0.0
  * @category Array
  * @param {Array} array The array to modify.
- * @param {...(number|number[])} [indexes] The indexes of elements to remove,
- *  specified individually or in arrays.
+ * @param {...(number|number[])} [indexes] The indexes of elements to remove.
  * @returns {Array} Returns the new array of removed elements.
  * @example
  *
diff --git a/rearg.js b/rearg.js
index 8990017c9..caaa0328b 100644
--- a/rearg.js
+++ b/rearg.js
@@ -16,8 +16,7 @@ var REARG_FLAG = 256;
  * @since 3.0.0
  * @category Function
  * @param {Function} func The function to rearrange arguments for.
- * @param {...(number|number[])} indexes The arranged argument indexes,
- *  specified individually or in arrays.
+ * @param {...(number|number[])} indexes The arranged argument indexes.
  * @returns {Function} Returns the new function.
  * @example
  *
diff --git a/result.js b/result.js
index f6d0bbb5d..8565004e4 100644
--- a/result.js
+++ b/result.js
@@ -1,4 +1,4 @@
-import baseCastPath from './_baseCastPath';
+import castPath from './_castPath';
 import isFunction from './isFunction';
 import isKey from './_isKey';
 
@@ -32,7 +32,7 @@ import isKey from './_isKey';
  * // => 'default'
  */
 function result(object, path, defaultValue) {
-  path = isKey(path, object) ? [path] : baseCastPath(path);
+  path = isKey(path, object) ? [path] : castPath(path);
 
   var index = -1,
       length = path.length;
diff --git a/sortBy.js b/sortBy.js
index edb45a3b9..9fe3665bc 100644
--- a/sortBy.js
+++ b/sortBy.js
@@ -15,8 +15,7 @@ import rest from './rest';
  * @category Collection
  * @param {Array|Object} collection The collection to iterate over.
  * @param {...(Array|Array[]|Function|Function[]|Object|Object[]|string|string[])}
- *  [iteratees=[_.identity]] The iteratees to sort by, specified individually
- *  or in arrays.
+ *  [iteratees=[_.identity]] The iteratees to sort by.
  * @returns {Array} Returns the new sorted array.
  * @example
  *
@@ -46,7 +45,7 @@ var sortBy = rest(function(collection, iteratees) {
   if (length > 1 && isIterateeCall(collection, iteratees[0], iteratees[1])) {
     iteratees = [];
   } else if (length > 2 && isIterateeCall(iteratees[0], iteratees[1], iteratees[2])) {
-    iteratees.length = 1;
+    iteratees = [iteratees[0]];
   }
   return baseOrderBy(collection, baseFlatten(iteratees, 1), []);
 });
diff --git a/split.js b/split.js
index 773ce73bc..2452e01b2 100644
--- a/split.js
+++ b/split.js
@@ -1,18 +1,12 @@
+import castSlice from './_castSlice';
+import isIterateeCall from './_isIterateeCall';
 import isRegExp from './isRegExp';
+import reHasComplexSymbol from './_reHasComplexSymbol';
 import stringToArray from './_stringToArray';
 import toString from './toString';
 
-/** 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 + ']');
+/** Used as references for the maximum length and index of an array. */
+var MAX_ARRAY_LENGTH = 4294967295;
 
 /**
  * Splits `string` by `separator`.
@@ -34,6 +28,13 @@ var reHasComplexSymbol = RegExp('[' + rsZWJ + rsAstralRange  + rsComboMarksRange
  * // => ['a', 'b']
  */
 function split(string, separator, limit) {
+  if (limit && typeof limit != 'number' && isIterateeCall(string, separator, limit)) {
+    separator = limit = undefined;
+  }
+  limit = limit === undefined ? MAX_ARRAY_LENGTH : limit >>> 0;
+  if (!limit) {
+    return [];
+  }
   string = toString(string);
   if (string && (
         typeof separator == 'string' ||
@@ -41,8 +42,7 @@ function split(string, separator, limit) {
       )) {
     separator += '';
     if (separator == '' && reHasComplexSymbol.test(string)) {
-      var strSymbols = stringToArray(string);
-      return limit === undefined ? strSymbols : strSymbols.slice(0, limit < 0 ? 0 : limit);
+      return castSlice(stringToArray(string), 0, limit);
     }
   }
   return string.split(separator, limit);
diff --git a/spread.js b/spread.js
index debde0b4d..94923335f 100644
--- a/spread.js
+++ b/spread.js
@@ -1,5 +1,6 @@
 import apply from './_apply';
 import arrayPush from './_arrayPush';
+import castSlice from './_castSlice';
 import rest from './rest';
 import toInteger from './toInteger';
 
@@ -50,7 +51,7 @@ function spread(func, start) {
   start = start === undefined ? 0 : nativeMax(toInteger(start), 0);
   return rest(function(args) {
     var array = args[start],
-        otherArgs = args.slice(0, start);
+        otherArgs = castSlice(args, 0, start);
 
     if (array) {
       arrayPush(otherArgs, array);
diff --git a/toPath.js b/toPath.js
index 4d5faee08..dc277f4cc 100644
--- a/toPath.js
+++ b/toPath.js
@@ -1,9 +1,9 @@
 import arrayMap from './_arrayMap';
-import baseCastKey from './_baseCastKey';
 import copyArray from './_copyArray';
 import isArray from './isArray';
 import isSymbol from './isSymbol';
 import stringToPath from './_stringToPath';
+import toKey from './_toKey';
 
 /**
  * Converts `value` to a property path array.
@@ -33,7 +33,7 @@ import stringToPath from './_stringToPath';
  */
 function toPath(value) {
   if (isArray(value)) {
-    return arrayMap(value, baseCastKey);
+    return arrayMap(value, toKey);
   }
   return isSymbol(value) ? [value] : copyArray(stringToPath(value));
 }
diff --git a/toString.js b/toString.js
index 989b014a7..5a3b4d7f1 100644
--- a/toString.js
+++ b/toString.js
@@ -9,8 +9,8 @@ var symbolProto = Symbol ? Symbol.prototype : undefined,
     symbolToString = symbolProto ? symbolProto.toString : undefined;
 
 /**
- * Converts `value` to a string if it's not one. An empty string is returned
- * for `null` and `undefined` values. The sign of `-0` is preserved.
+ * Converts `value` to a string. An empty string is returned for `null`
+ * and `undefined` values. The sign of `-0` is preserved.
  *
  * @static
  * @memberOf _
diff --git a/trim.js b/trim.js
index eff4ec95f..2eef9e40d 100644
--- a/trim.js
+++ b/trim.js
@@ -1,3 +1,4 @@
+import castSlice from './_castSlice';
 import charsEndIndex from './_charsEndIndex';
 import charsStartIndex from './_charsStartIndex';
 import stringToArray from './_stringToArray';
@@ -36,16 +37,15 @@ function trim(string, chars, guard) {
   if (guard || chars === undefined) {
     return string.replace(reTrim, '');
   }
-  chars = (chars + '');
-  if (!chars) {
+  if (!(chars += '')) {
     return string;
   }
   var strSymbols = stringToArray(string),
-      chrSymbols = stringToArray(chars);
+      chrSymbols = stringToArray(chars),
+      start = charsStartIndex(strSymbols, chrSymbols),
+      end = charsEndIndex(strSymbols, chrSymbols) + 1;
 
-  return strSymbols
-    .slice(charsStartIndex(strSymbols, chrSymbols), charsEndIndex(strSymbols, chrSymbols) + 1)
-    .join('');
+  return castSlice(strSymbols, start, end).join('');
 }
 
 export default trim;
diff --git a/trimEnd.js b/trimEnd.js
index 6eef62b7b..f3a9962ad 100644
--- a/trimEnd.js
+++ b/trimEnd.js
@@ -1,3 +1,4 @@
+import castSlice from './_castSlice';
 import charsEndIndex from './_charsEndIndex';
 import stringToArray from './_stringToArray';
 import toString from './toString';
@@ -32,14 +33,13 @@ function trimEnd(string, chars, guard) {
   if (guard || chars === undefined) {
     return string.replace(reTrimEnd, '');
   }
-  chars = (chars + '');
-  if (!chars) {
+  if (!(chars += '')) {
     return string;
   }
-  var strSymbols = stringToArray(string);
-  return strSymbols
-    .slice(0, charsEndIndex(strSymbols, stringToArray(chars)) + 1)
-    .join('');
+  var strSymbols = stringToArray(string),
+      end = charsEndIndex(strSymbols, stringToArray(chars)) + 1;
+
+  return castSlice(strSymbols, 0, end).join('');
 }
 
 export default trimEnd;
diff --git a/trimStart.js b/trimStart.js
index 26b9395a1..ddcba5d76 100644
--- a/trimStart.js
+++ b/trimStart.js
@@ -1,3 +1,4 @@
+import castSlice from './_castSlice';
 import charsStartIndex from './_charsStartIndex';
 import stringToArray from './_stringToArray';
 import toString from './toString';
@@ -32,14 +33,13 @@ function trimStart(string, chars, guard) {
   if (guard || chars === undefined) {
     return string.replace(reTrimStart, '');
   }
-  chars = (chars + '');
-  if (!chars) {
+  if (!(chars += '')) {
     return string;
   }
-  var strSymbols = stringToArray(string);
-  return strSymbols
-    .slice(charsStartIndex(strSymbols, stringToArray(chars)))
-    .join('');
+  var strSymbols = stringToArray(string),
+      start = charsStartIndex(strSymbols, stringToArray(chars));
+
+  return castSlice(strSymbols, start).join('');
 }
 
 export default trimStart;
diff --git a/truncate.js b/truncate.js
index f93ae1e2d..a9cc9a0e1 100644
--- a/truncate.js
+++ b/truncate.js
@@ -1,5 +1,7 @@
+import castSlice from './_castSlice';
 import isObject from './isObject';
 import isRegExp from './isRegExp';
+import reHasComplexSymbol from './_reHasComplexSymbol';
 import stringSize from './_stringSize';
 import stringToArray from './_stringToArray';
 import toInteger from './toInteger';
@@ -12,18 +14,6 @@ var DEFAULT_TRUNC_LENGTH = 30,
 /** Used to match `RegExp` flags from their coerced string values. */
 var reFlags = /\w*$/;
 
-/** 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 + ']');
-
 /**
  * Truncates `string` if it's longer than the given maximum string length.
  * The last characters of the truncated string are replaced with the omission
@@ -85,7 +75,7 @@ function truncate(string, options) {
     return omission;
   }
   var result = strSymbols
-    ? strSymbols.slice(0, end).join('')
+    ? castSlice(strSymbols, 0, end).join('')
     : string.slice(0, end);
 
   if (separator === undefined) {
diff --git a/update.js b/update.js
index 7a7b0a1f3..ec4bbe332 100644
--- a/update.js
+++ b/update.js
@@ -1,5 +1,5 @@
-import baseCastFunction from './_baseCastFunction';
 import baseUpdate from './_baseUpdate';
+import castFunction from './_castFunction';
 
 /**
  * This method is like `_.set` except that accepts `updater` to produce the
@@ -29,7 +29,7 @@ import baseUpdate from './_baseUpdate';
  * // => 0
  */
 function update(object, path, updater) {
-  return object == null ? object : baseUpdate(object, path, baseCastFunction(updater));
+  return object == null ? object : baseUpdate(object, path, castFunction(updater));
 }
 
 export default update;
diff --git a/updateWith.js b/updateWith.js
index 68a571db1..528ef2f4b 100644
--- a/updateWith.js
+++ b/updateWith.js
@@ -1,5 +1,5 @@
-import baseCastFunction from './_baseCastFunction';
 import baseUpdate from './_baseUpdate';
+import castFunction from './_castFunction';
 
 /**
  * This method is like `_.update` except that it accepts `customizer` which is
@@ -27,7 +27,7 @@ import baseUpdate from './_baseUpdate';
  */
 function updateWith(object, path, updater, customizer) {
   customizer = typeof customizer == 'function' ? customizer : undefined;
-  return object == null ? object : baseUpdate(object, path, baseCastFunction(updater), customizer);
+  return object == null ? object : baseUpdate(object, path, castFunction(updater), customizer);
 }
 
 export default updateWith;
diff --git a/words.js b/words.js
index 65f297732..27ce8391f 100644
--- a/words.js
+++ b/words.js
@@ -1,5 +1,8 @@
 import toString from './toString';
 
+/** Used to match non-compound words composed of alphanumeric characters. */
+var reBasicWord = /[a-zA-Z0-9]+/g;
+
 /** Used to compose unicode character classes. */
 var rsAstralRange = '\\ud800-\\udfff',
     rsComboMarksRange = '\\u0300-\\u036f\\ufe20-\\ufe23',
@@ -38,9 +41,6 @@ var rsLowerMisc = '(?:' + rsLower + '|' + rsMisc + ')',
     rsSeq = rsOptVar + reOptMod + rsOptJoin,
     rsEmoji = '(?:' + [rsDingbat, rsRegional, rsSurrPair].join('|') + ')' + rsSeq;
 
-/** Used to match non-compound words composed of alphanumeric characters. */
-var reBasicWord = /[a-zA-Z0-9]+/g;
-
 /** Used to match complex or compound words. */
 var reComplexWord = RegExp([
   rsUpper + '?' + rsLower + '+(?=' + [rsBreak, rsUpper, '$'].join('|') + ')',
diff --git a/wrapperAt.js b/wrapperAt.js
index 4eee46c87..bc82ec1b9 100644
--- a/wrapperAt.js
+++ b/wrapperAt.js
@@ -13,8 +13,7 @@ import thru from './thru';
  * @memberOf _
  * @since 1.0.0
  * @category Seq
- * @param {...(string|string[])} [paths] The property paths of elements to pick,
- *  specified individually or in arrays.
+ * @param {...(string|string[])} [paths] The property paths of elements to pick.
  * @returns {Object} Returns the new `lodash` wrapper instance.
  * @example
  *