Issue 6931 - Allow content filters for localhost

lib/filterClasses.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 1113 matching lines @@
   if (domains && /(^|,)~?(,|$)/.test(domains))
     return new InvalidFilter(text, "filter_invalid_domain");
 
   if (type == "@")
     return new ElemHideException(text, domains, body);
 
   if (type == "?" || type == "$")
   {
     // Element hiding emulation and snippet filters are inefficient so we need
     // to make sure that they're only applied if they specify active domains
-    if (!/,[^~][^,.]*\.[^,]/.test("," + domains) &&
-        domains.toLowerCase() != "localhost")
+    if (!(/,[^~][^,.]*\.[^,]/.test("," + domains) ||
+          ("," + domains + ",").includes(",localhost,")))
     {
       return new InvalidFilter(text, type == "?" ?
                                        "filter_elemhideemulation_nodomain" :
                                        "filter_snippet_nodomain");
     }
 
     if (type == "?")
       return new ElemHideEmulationFilter(text, domains, body);
 
     return new SnippetFilter(text, domains, body);
@@ skipping 102 matching lines @@
 
   /**
    * Script that should be executed
    * @type {string}
    */
   get script()
   {
     return this.body;
   }
 });