[adblockplusui] Issue 4915 - Define ext for background pages in antiadblockInit.js

lib/antiadblockInit.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/>.
  */
 
 Cu.import("resource://gre/modules/Services.jsm");
 
 let {Utils} = require("utils");
 let {Prefs} = require("prefs");
 let {ActiveFilter} = require("filterClasses");
 let {FilterStorage} = require("filterStorage");
 let {FilterNotifier} = require("filterNotifier");
 let {Subscription} = require("subscriptionClasses");
 let {Notification} = require("notification");
 
-let ext = (
-  typeof window != "undefined" && window.ext ?
-  window.ext :
-  require("ext_background")
-);

[Sebastian Noack, 2017/02/20 16:27:25]

For reference, if it wouldn't be for ESLint's non-undef rule, this could be as
simple as:

  let ext = typeof ext != "undefined" ? ext : require("ext_background");

But even without directly accessing global variables from other scripts, it can
still be a little simpler:

  let ext = typeof window != "undefined" &&
            window.ext || require("ext_background");

[wspee, 2017/03/01 14:53:38]

Done.

[Wladimir Palant, 2017/03/02 11:14:39]

That wouldn't work, ESLint isn't spoiling the fun here but rather preventing a
bug. ext refers to the local let variable here, not to the global one you would
be interested in.
No, not simpler but clearly more obfuscated.

+let ext;
+if (typeof window != "undefined" && window.ext)
+  ext = window.ext;
+else
+  ext = require("ext_background");
 
 exports.initAntiAdblockNotification = function initAntiAdblockNotification()
 {
   let notification = {
     id: "antiadblock",
     type: "question",
     title: ext.i18n.getMessage("notification_antiadblock_title"),
     message: ext.i18n.getMessage("notification_antiadblock_message"),
     urlFilters: []
   };
@@ skipping 44 matching lines @@
     if (url in FilterStorage.knownSubscriptions && !subscription.disabled)
       addAntiAdblockNotification(subscription);
     else
       removeAntiAdblockNotification();
   }
 
   FilterNotifier.on("subscription.updated", onSubscriptionChange);
   FilterNotifier.on("subscription.removed", onSubscriptionChange);
   FilterNotifier.on("subscription.disabled", onSubscriptionChange);
 }