From 61251b305ddfc043ab565d01f948c61c2d7dfadd Mon Sep 17 00:00:00 2001
From: John-David Dalton <john.david.dalton@gmail.com>
Date: Fri, 31 Jul 2015 14:02:59 -0700
Subject: [PATCH] Simplify `_.escapeRegExp` to align with the defunct ES7
 proposal.

---
 lodash.js    | 15 +++++++--------
 test/test.js | 38 ++++----------------------------------
 2 files changed, 11 insertions(+), 42 deletions(-)

diff --git a/lodash.js b/lodash.js
index bae836735..ca337d8ad 100644
--- a/lodash.js
+++ b/lodash.js
@@ -94,10 +94,9 @@
       rePropName = /[^.[\]]+|\[(?:(-?\d+(?:\.\d+)?)|(["'])((?:(?!\2)[^\n\\]|\\.)*?)\2)\]/g;
 
   /**
-   * Used to match `RegExp` [syntax characters](http://ecma-international.org/ecma-262/6.0/#sec-patterns)
-   * and those outlined by [`EscapeRegExpPattern`](http://ecma-international.org/ecma-262/6.0/#sec-escaperegexppattern).
+   * Used to match `RegExp` [syntax characters](http://ecma-international.org/ecma-262/6.0/#sec-patterns).
    */
-  var reRegExpChars = /^[:!,]|[\\^$.*+?()[\]{}|\/]|(^[0-9a-fA-Fnrtuvx])|([\n\r\u2028\u2029])/g,
+  var reRegExpChars = /[\\^$.*+?()[\]{}|]/g,
       reHasRegExpChars = RegExp(reRegExpChars.source);
 
   /** Used to match [combining diacritical marks](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks). */
@@ -9805,8 +9804,8 @@
     }
 
     /**
-     * Escapes the `RegExp` special characters "\", "/", "^", "$", ".", "|", "?",
-     * "*", "+", "(", ")", "[", "]", "{" and "}" in `string`.
+     * Escapes the `RegExp` special characters "^", "$", "\", ".", "*", "+",
+     * "?", "(", ")", "[", "]", "{", "}", and "|" in `string`.
      *
      * @static
      * @memberOf _
@@ -9816,13 +9815,13 @@
      * @example
      *
      * _.escapeRegExp('[lodash](https://lodash.com/)');
-     * // => '\[lodash\]\(https:\/\/lodash\.com\/\)'
+     * // => '\[lodash\]\(https://lodash\.com/\)'
      */
     function escapeRegExp(string) {
       string = baseToString(string);
       return (string && reHasRegExpChars.test(string))
-        ? string.replace(reRegExpChars, escapeRegExpChar)
-        : (string || '(?:)');
+        ? string.replace(reRegExpChars, '\\$&')
+        : string;
     }
 
     /**
diff --git a/test/test.js b/test/test.js
index d2add8bc1..580072c4f 100644
--- a/test/test.js
+++ b/test/test.js
@@ -287,15 +287,6 @@
     new URIError
   ];
 
-  /** Used to check escaped regexp characters. */
-  var regexpEscapes = {
-    '0': 'x30', '1': 'x31', '2': 'x32', '3': 'x33', '4': 'x34',
-    '5': 'x35', '6': 'x36', '7': 'x37', '8': 'x38', '9': 'x39',
-    'A': 'x41', 'B': 'x42', 'C': 'x43', 'D': 'x44', 'E': 'x45', 'F': 'x46',
-    'a': 'x61', 'b': 'x62', 'c': 'x63', 'd': 'x64', 'e': 'x65', 'f': 'x66',
-    'n': 'x6e', 'r': 'x72', 't': 'x74', 'u': 'x75', 'v': 'x76', 'x': 'x78'
-  };
-
   /** Used to check whether methods support typed arrays. */
   var typedArrays = [
     'Float32Array',
@@ -3609,41 +3600,20 @@
   QUnit.module('lodash.escapeRegExp');
 
   (function() {
-    var escaped = '\\/\\^\\$\\.\\*\\+\\?\\(\\)\\[\\]\\{\\}\\|\\n\\r\\u2028\\u2029\\\\',
-        unescaped = '/^$.*+?()[]{}|\n\r\u2028\u2029\\';
+    var escaped = '\\^\\$\\.\\*\\+\\?\\(\\)\\[\\]\\{\\}\\|\\\\',
+        unescaped = '^$.*+?()[]{}|\\';
 
     test('should escape values', 1, function() {
       strictEqual(_.escapeRegExp(unescaped + unescaped), escaped + escaped);
     });
 
-    test('should escape special characters at the start of a string', 1, function() {
-      var chars = [
-        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
-        'a', 'b', 'c', 'd', 'e', 'f',
-        'A', 'B', 'C', 'D', 'E', 'F',
-        'n', 'r', 't', 'u', 'v', 'x',
-        ':', '!', ','
-      ];
-
-      var expected = _.map(chars, function(chr) {
-        var escaped = '\\' + (regexpEscapes[chr] || chr);
-        return [escaped, escaped + 'z', 'z' + chr];
-      });
-
-      var actual = _.map(chars, function(chr) {
-        return [_.escapeRegExp(chr), _.escapeRegExp(chr + 'z'), _.escapeRegExp('z' + chr)];
-      });
-
-      deepEqual(actual, expected);
-    });
-
     test('should handle strings with nothing to escape', 1, function() {
       strictEqual(_.escapeRegExp('ghi'), 'ghi');
     });
 
-    test('should return `"(?:)"` when provided nullish or empty string values', 1, function() {
+    test('should return an empty string for empty values', 1, function() {
       var values = [, null, undefined, ''],
-          expected = _.map(values, _.constant('(?:)'));
+          expected = _.map(values, _.constant(''));
 
       var actual = _.map(values, function(value, index) {
         return index ? _.escapeRegExp(value) : _.escapeRegExp();