Optimize createPadding for the common case.

lodash.js

@@ -3511,6 +3511,34 @@
       return result;
     }
 
+    /**
+     * The base implementation of `_.repeat` which doesn't coerce arguments.
+     *
+     * @private
+     * @param {string} string The string to repeat.
+     * @param {number} n The number of times to repeat the string.
+     * @returns {string} Returns the repeated string.
+     */
+    function baseRepeat(string, n) {
+      var result = '';
+      if (!string || n < 1 || n > MAX_SAFE_INTEGER) {
+        return result;
+      }
+      // Leverage the exponentiation by squaring algorithm for a faster repeat.
+      // See https://en.wikipedia.org/wiki/Exponentiation_by_squaring for more details.
+      do {
+        if (n % 2) {
+          result += string;
+        }
+        n = nativeFloor(n / 2);
+        if (n) {
+          string += string;
+        }
+      } while (n);
+
+      return result;
+    }
+
     /**
      * The base implementation of `_.set`.
      *
@@ -4560,14 +4588,18 @@
       if (!length || strLength >= length) {
         return '';
       }
-      var padLength = length - strLength;
       chars = chars === undefined ? ' ' : (chars + '');
       chars = chars == '' ? ' ' : chars;
+      length -= strLength;
 
-      var result = repeat(chars, nativeCeil(padLength / stringSize(chars)));
+      var charsLength = chars.length;
+      if (charsLength == 1) {
+        return baseRepeat(chars, length);
+      }
+      var result = baseRepeat(chars, nativeCeil(length / stringSize(chars)));
       return reHasComplexSymbol.test(chars)
-        ? stringToArray(result).slice(0, padLength).join('')
-        : result.slice(0, padLength);
+        ? stringToArray(result).slice(0, length).join('')
+        : result.slice(0, length);
     }
 
     /**
@@ -13170,26 +13202,7 @@
      * // => ''
      */
     function repeat(string, n) {
-      string = toString(string);
-      n = toInteger(n);
-
-      var result = '';
-      if (!string || n < 1 || n > MAX_SAFE_INTEGER) {
-        return result;
-      }
-      // Leverage the exponentiation by squaring algorithm for a faster repeat.
-      // See https://en.wikipedia.org/wiki/Exponentiation_by_squaring for more details.
-      do {
-        if (n % 2) {
-          result += string;
-        }
-        n = nativeFloor(n / 2);
-        if (n) {
-          string += string;
-        }
-      } while (n);
-
-      return result;
+      return baseRepeat(toString(string), toInteger(n));
     }
 
     /**
@@ -14107,13 +14120,13 @@
 
     /**
      * Creates a function that invokes `func` with the arguments of the created
-     * function. If `func` is a property name the created callback returns the
-     * property value for a given element. If `func` is an object the created
-     * callback returns `true` for elements that contain the equivalent object
-     * properties, otherwise it returns `false`.
+     * 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`.
      *
      * @static
-     * @since 0.1.0
+     * @since 4.0.0
      * @memberOf _
      * @category Util
      * @param {*} [func=_.identity] The value to convert to a callback.
@@ -14121,20 +14134,31 @@
      * @example
      *
      * var users = [
-     *   { 'user': 'barney', 'age': 36 },
-     *   { 'user': 'fred',   'age': 40 }
+     *   { 'user': 'barney', 'age': 36, 'active': true },
+     *   { 'user': 'fred',   'age': 40, 'active': false }
      * ];
      *
+     * // The `_.matches` iteratee shorthand.
+     * _.filter(users, _.iteratee({ 'user': 'barney', 'active': true }));
+     * // => [{ 'user': 'barney', 'age': 36, 'active': true }]
+     *
+     * // The `_.matchesProperty` iteratee shorthand.
+     * _.filter(users, _.iteratee(['user', 'fred']));
+     * // => [{ 'user': 'fred', 'age': 40 }]
+     *
+     * // The `_.property` iteratee shorthand.
+     * _.map(users, _.iteratee('user'));
+     * // => ['barney', 'fred']
+     *
      * // Create custom iteratee shorthands.
-     * _.iteratee = _.wrap(_.iteratee, function(callback, func) {
-     *   var p = /^(\S+)\s*([<>])\s*(\S+)$/.exec(func);
-     *   return !p ? callback(func) : function(object) {
-     *     return (p[2] == '>' ? object[p[1]] > p[3] : object[p[1]] < p[3]);
+     * _.iteratee = _.wrap(_.iteratee, function(iteratee, func) {
+     *   return !_.isRegExp(func) ? iteratee(func) : function(string) {
+     *     return func.test(string);
      *   };
      * });
      *
-     * _.filter(users, 'age > 36');
-     * // => [{ 'user': 'fred', 'age': 40 }]
+     * _.filter(['abc', 'def'], /ef/);
+     * // => ['def']
      */
     function iteratee(func) {
       return baseIteratee(typeof func == 'function' ? func : baseClone(func, true));