Issue 7303 - Deprecate the use of String.prototype.substr()

lib/common.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 184 matching lines @@
 {
   let qualifiedSelector = "";
 
   for (let sub of splitSelector(selector))
   {
     sub = sub.trim();
 
     qualifiedSelector += ", ";
 
     let index = findTargetSelectorIndex(sub);
-    let [, type = "", rest] = /^([a-z][a-z-]*)?(.*)/i.exec(sub.substr(index));
+    let [, type = "", rest] = /^([a-z][a-z-]*)?(.*)/i.exec(sub.substring(index));
 
     // Note that the first group in the regular expression is optional. If it
     // doesn't match (e.g. "#foo::nth-child(1)"), type will be an empty string.
-    qualifiedSelector += sub.substr(0, index) + type + qualifier + rest;
+    qualifiedSelector += sub.substring(0, index) + type + qualifier + rest;
   }
 
   // Remove the initial comma and space.
-  return qualifiedSelector.substr(2);
+  return qualifiedSelector.substring(2);
 }
 
 exports.qualifySelector = qualifySelector;