Issue 4795 - Use modern JavaScript syntax

background.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/>.
  */
 
-var RegExpFilter = require("filterClasses").RegExpFilter;
-var ElemHide = require("elemHide").ElemHide;
-var checkWhitelisted = require("whitelisting").checkWhitelisted;
-var extractHostFromFrame = require("url").extractHostFromFrame;
-var port = require("messaging").port;
-var devtools = require("devtools");
+"use strict";
 
-port.on("get-selectors", function(msg, sender)
+const {RegExpFilter} = require("filterClasses");
+const {ElemHide} = require("elemHide");
+const {checkWhitelisted} = require("whitelisting");
+const {extractHostFromFrame} = require("url");
+const {port} = require("messaging");
+const devtools = require("devtools");
+
+port.on("get-selectors", (msg, sender) =>
 {
-  var selectors;
-  var trace = devtools && devtools.hasPanel(sender.page);
+  let selectors;
+  let trace = devtools && devtools.hasPanel(sender.page);
 
   if (!checkWhitelisted(sender.page, sender.frame,
                         RegExpFilter.typeMap.DOCUMENT |
                         RegExpFilter.typeMap.ELEMHIDE))
   {
-    var specificOnly = checkWhitelisted(sender.page, sender.frame,
+    let specificOnly = checkWhitelisted(sender.page, sender.frame,
                                         RegExpFilter.typeMap.GENERICHIDE);
     selectors = ElemHide.getSelectorsForDomain(
       extractHostFromFrame(sender.frame),
       specificOnly ? ElemHide.SPECIFIC_ONLY : ElemHide.ALL_MATCHING
     );
   }
   else
   {
     selectors = [];
   }
 
   return {selectors: selectors, trace: trace};
 });
 
-port.on("forward", function(msg, sender)
+port.on("forward", (msg, sender) =>
 {
-  var targetPage;
+  let targetPage;
   if (msg.targetPageId)
     targetPage = ext.getPage(msg.targetPageId);
   else
     targetPage = sender.page;
 
   if (targetPage)
   {
     msg.payload.sender = sender.page.id;
     if (msg.expectsResponse)
       return new Promise(targetPage.sendMessage.bind(targetPage, msg.payload));
     targetPage.sendMessage(msg.payload);
   }
 });