Issue 4783 - Use modern JavaScript syntax for the messageResponder

messageResponder.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 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
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 "use strict";
 
 {
   var ext = ext || require("ext_background");
 
   const {port} = require("messaging");
   const {Prefs} = require("prefs");
   const {Utils} = require("utils");
   const {FilterStorage} = require("filterStorage");
   const {FilterNotifier} = require("filterNotifier");
   const {defaultMatcher} = require("matcher");
   const {ElemHideEmulation} = require("elemHideEmulation");
-  const {NotificationStorage} = require("notification");

[Thomas Greiner, 2017/01/18 11:40:09]

This doesn't work. What you'd want to do is:

const {Notification: NotificationStorage} = require("notification");

[kzar, 2017/01/18 11:54:41]

Done.

+  const {Notification: NotificationStorage} = require("notification");
 
   const {Filter, BlockingFilter, RegExpFilter} = require("filterClasses");
   const {Synchronizer} = require("synchronizer");
 
   const info = require("info");
   const {Subscription,
          DownloadableSubscription,
          SpecialSubscription} = require("subscriptionClasses");
 
   // Some modules doesn't exist on Firefox. Moreover,
@@ skipping 90 matching lines @@
       {
         listenedFilterChanges[name] = null;
         FilterNotifier.on(name, function()
         {
           let args = [type, action];
           for (let arg of arguments)
             args.push(arg);
           sendMessage.apply(null, args);
         });
       }
-    };

[Thomas Greiner, 2017/01/18 11:40:09]

Detail: This semicolon is still left over from your previous change.

[kzar, 2017/01/18 11:54:41]

Whoops, Done.

+    }
   }
 
   function getListenerFilters(page)
   {
     let listenerFilters = changeListeners.get(page);
     if (!listenerFilters)
     {
       listenerFilters = Object.create(null);
       changeListeners.set(page, listenerFilters);
     }
@@ skipping 77 matching lines @@
   {
     if (message.what == "elemhideemulation")
     {
       let filters = [];
       const {checkWhitelisted} = require("whitelisting");
 
       if (Prefs.enabled && !checkWhitelisted(sender.page, sender.frame,
                             RegExpFilter.typeMap.DOCUMENT |
                             RegExpFilter.typeMap.ELEMHIDE))
       {
-        const hostname = sender.frame.url.hostname;

[Thomas Greiner, 2017/01/18 11:40:09]

Detail: I don't see a compelling enough use-case for using `const` here. The
`hostname` variable should be allowed to change to allow for maximum flexibility
when maintaining this part of the code.

[kzar, 2017/01/18 11:54:41]

Done.

+        let hostname = sender.frame.url.hostname;
         filters = ElemHideEmulation.getRulesForDomain(hostname);
         filters = filters.map(filter =>
         {
           return {
             selector: filter.selector,
             text: filter.text
           };
         });
       }
       return filters;
@@ skipping 175 matching lines @@
   {
     let subscriptions = message.url ? [Subscription.fromURL(message.url)] :
                         FilterStorage.subscriptions;
     for (let subscription of subscriptions)
     {
       if (subscription instanceof DownloadableSubscription)
         Synchronizer.execute(subscription, true);
     }
   });
 }