Bump to v4.0.0.

internal/createPadding.js

@@ -1,29 +1,46 @@
-define(['../string/repeat', './root'], function(repeat, root) {
+define(['../repeat', './stringSize', './stringToArray', '../toInteger'], function(repeat, stringSize, stringToArray, toInteger) {
 
-  /* Native method references for those with the same name as other `lodash` methods. */
-  var nativeCeil = Math.ceil,
-      nativeIsFinite = root.isFinite;
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
+  /** Used to compose unicode character classes. */
+  var rsAstralRange = '\\ud800-\\udfff',
+      rsComboRange = '\\u0300-\\u036f\\ufe20-\\ufe23',
+      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 + rsComboRange + rsVarRange + ']');
+
+  /* Built-in method references for those with the same name as other `lodash` methods. */
+  var nativeCeil = Math.ceil;
 
   /**
-   * Creates the padding required for `string` based on the given `length`.
-   * The `chars` string is truncated if the number of characters exceeds `length`.
+   * Creates the padding for `string` based on `length`. The `chars` string
+   * is truncated if the number of characters exceeds `length`.
    *
    * @private
    * @param {string} string The string to create padding for.
    * @param {number} [length=0] The padding length.
    * @param {string} [chars=' '] The string used as padding.
-   * @returns {string} Returns the pad for `string`.
+   * @returns {string} Returns the padding for `string`.
    */
   function createPadding(string, length, chars) {
-    var strLength = string.length;
-    length = +length;
+    length = toInteger(length);
 
-    if (strLength >= length || !nativeIsFinite(length)) {
+    var strLength = stringSize(string);
+    if (!length || strLength >= length) {
       return '';
     }
     var padLength = length - strLength;
-    chars = chars == null ? ' ' : (chars + '');
-    return repeat(chars, nativeCeil(padLength / chars.length)).slice(0, padLength);
+    chars = chars === undefined ? ' ' : (chars + '');
+
+    var result = repeat(chars, nativeCeil(padLength / stringSize(chars)));
+    return reHasComplexSymbol.test(chars)
+      ? stringToArray(result).slice(0, padLength).join('')
+      : result.slice(0, padLength);
   }
 
   return createPadding;