Issue 4871 - Have ESLint pass 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";
 
 {
   if (typeof ext == "undefined")

[kzar, 2017/02/08 08:39:24]

(This change is required since we'll be using `let` instead of `var` to declare
`ext` in adblockpluschrome when the related ESLint changes land there.)

     window.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 {Notification: NotificationStorage} = require("notification");
@@ skipping 52 matching lines @@
     pref: "prefs.respond",
     subscription: "subscriptions.respond"
   };
 
   function sendMessage(type, action, ...args)
   {
     let pages = changeListeners.keys();
     if (pages.length == 0)
       return;
 
     for (let i = 0; i < args.length; i++)

[Thomas Greiner, 2017/02/08 10:11:09]

Why not use a for-of loop instead to simplify the code?

[kzar, 2017/02/08 10:27:24]

Since we need to replace some arguments in place.

[Thomas Greiner, 2017/02/08 10:37:26]

Ah, don't know how I overlooked that. :p You're of course absolutely right.

Usually we'd use `Array.map()` for that instead of a for-loop so not sure why it
wasn't used here. Anyway, no need to make this change if you consider it to be
out of scope for this review.

     {
       let arg = args[i];
       if (arg instanceof Subscription)
         args[i] = convertSubscription(arg);
       else if (arg instanceof Filter)
         args[i] = convertFilter(arg);
     }
 
     for (let page of pages)
     {
@@ skipping 18 matching lines @@
       if (type == "filter" && action == "loaded")
         name = "load";
       else
         name = type + "." + action;
 
       if (!(name in listenedFilterChanges))
       {
         listenedFilterChanges[name] = null;
         FilterNotifier.on(name, () =>
         {
-          sendMessage(...[type, action].concat(args));

[Thomas Greiner, 2017/02/08 10:11:09]

Looks like a more complicated way of writing `sendMessage(type, action,
...args)`.

[kzar, 2017/02/08 10:27:24]

Good point, Done.

+          sendMessage(type, action, ...args);
         });
       }
     }
   }
 
   function getListenerFilters(page)
   {
     let listenerFilters = changeListeners.get(page);
     if (!listenerFilters)
     {
@@ skipping 15 matching lines @@
     }
 
     if (message.what == "doclink")
       return Utils.getDocLink(message.link);
 
     if (message.what == "localeInfo")
     {
       let bidiDir;
       if ("chromeRegistry" in Utils)
       {
-        let rtl = Utils.chromeRegistry.isLocaleRTL("adblockplus");

[Thomas Greiner, 2017/02/08 10:11:09]

Detail: It'd be great if the variable name would reflect that it's a boolean by
calling it `isRtl` or `isRTL`.

[kzar, 2017/02/08 10:27:24]

Done.

-        bidiDir = rtl ? "rtl" : "ltr";
+        let isRtl = Utils.chromeRegistry.isLocaleRTL("adblockplus");
+        bidiDir = isRtl ? "rtl" : "ltr";
       }
       else
       {
         bidiDir = ext.i18n.getMessage("@@bidi_dir");
       }
 
       return {locale: Utils.appLocale, bidiDir};
     }
 
     if (message.what == "features")
@@ skipping 239 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);
     }
   });
 }