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

lib/common.js

Index: lib/common.js
===================================================================
--- a/lib/common.js
+++ b/lib/common.js
@@ -197,22 +197,22 @@
 
   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.
     // If `rest` is "*" then it is discarded.
     qualifiedSelector += sub.substring(0, index) + type + qualifier +
                          (rest != "*" ? rest : "");
   }
 
   // Remove the initial comma and space.
-  return qualifiedSelector.substr(2);
+  return qualifiedSelector.substring(2);
 }
 
 exports.qualifySelector = qualifySelector;