Issue 2259 - Removed non-standard JavaScript code from Element Hiding Helper

chrome/content/composer.js

 /*
  * This Source Code is subject to the terms of the Mozilla Public License
  * version 2.0 (the "License"). You can obtain a copy of the License at
  * http://mozilla.org/MPL/2.0/.
  */
 
 let {Prefs} = require("prefs");
 
 let domainData;
 let nodeData;
@@ skipping 230 matching lines @@
           else if (attr.value.substr(0, attr.selected.length) == attr.selected)
             op = "^=";
           else if (attr.value.substr(attr.value.length - attr.selected.length) == attr.selected)
             op = "$=";
   
           let useFallback = false;
           if (attr.name == "id" && op == "=")
             expression += "#" + escapeName(attr.selected).replace(/^([^a-zA-Z\\])/, escapeChar).replace(/\\(\s)$/, escapeChar);
           else if (attr.name == "class" && /\S/.test(attr.selected))
           {
-            let knownClasses = {};
-            for (let cls of attr.value.split(/\s+/))
-              knownClasses[cls] = true;
-
+            let knownClasses = new Set(attr.value.split(/\s+/));

[Sebastian Noack, 2015/04/04 15:30:21]

While introducing Sets and changing this code anyway, I think it makes sense to
use a Set here as well.

             let classes = attr.selected.split(/\s+/).filter(cls => cls != "");
-            if (classes.every(cls => knownClasses.hasOwnProperty(cls)))
+            if (classes.every(cls => knownClasses.has(cls)))
               expression += "." + classes.map(escapeName).join(".");
             else
               useFallback = true;
           }
           else
             useFallback = true;
 
           if (useFallback)
           {
             var escapedValue = attr.selected.replace(/(["\\])/g, '\\$1')
@@ skipping 364 matching lines @@
 
   fillAttributes(item.nodeData);
 }
 
 function addExpression()
 {
   AdblockPlus.addPatterns([document.getElementById("expression").value]);
 
   togglePreview(false);
 }