Bump to v4.15.0.

split.js

@@ -1,20 +1,14 @@
 import baseToString from './_baseToString.js';
 import castSlice from './_castSlice.js';
+import hasUnicode from './_hasUnicode.js';
 import isIterateeCall from './_isIterateeCall.js';
 import isRegExp from './isRegExp.js';
-import reHasComplexSymbol from './_reHasComplexSymbol.js';
 import stringToArray from './_stringToArray.js';
 import toString from './toString.js';
 
 /** Used as references for the maximum length and index of an array. */
 var MAX_ARRAY_LENGTH = 4294967295;
 
-/** Used for built-in method references. */
-var stringProto = String.prototype;
-
-/* Built-in method references for those with the same name as other `lodash` methods. */
-var nativeSplit = stringProto.split;
-
 /**
  * Splits `string` by `separator`.
  *
@@ -48,11 +42,11 @@ function split(string, separator, limit) {
         (separator != null && !isRegExp(separator))
       )) {
     separator = baseToString(separator);
-    if (separator == '' && reHasComplexSymbol.test(string)) {
+    if (!separator && hasUnicode(string)) {
       return castSlice(stringToArray(string), 0, limit);
     }
   }
-  return nativeSplit.call(string, separator, limit);
+  return string.split(separator, limit);
 }
 
 export default split;