Issue 4795 - Use modern JavaScript syntax

lib/subscriptionInit.js

Index: lib/subscriptionInit.js
diff --git a/lib/subscriptionInit.js b/lib/subscriptionInit.js
index 211fcb343adc88a79220ca2616899bc400c40357..1c530da32d57cd9e7bbfaf0e1269ea7ee29a9a53 100644
--- a/lib/subscriptionInit.js
+++ b/lib/subscriptionInit.js
@@ -19,14 +19,14 @@
 
 "use strict";
 
-let {Subscription, DownloadableSubscription,
-     SpecialSubscription} = require("subscriptionClasses");
-let {FilterStorage} = require("filterStorage");
-let {FilterNotifier} = require("filterNotifier");
-let {Prefs} = require("prefs");
-let {Synchronizer} = require("synchronizer");
-let {Utils} = require("utils");
-let {initNotifications} = require("notificationHelper");
+const {Subscription, DownloadableSubscription,
+       SpecialSubscription} = require("subscriptionClasses");
+const {FilterStorage} = require("filterStorage");
+const {FilterNotifier} = require("filterNotifier");
+const {Prefs} = require("prefs");
+const {Synchronizer} = require("synchronizer");
+const {Utils} = require("utils");
+const {initNotifications} = require("notificationHelper");
 
 let firstRun;
 let subscriptionsCallback = null;
@@ -180,7 +180,7 @@ exports.reinitialized = false;
  *
  * @param {function}
  */
-exports.setSubscriptionsCallback = function(callback)
+exports.setSubscriptionsCallback = callback =>
 {
   subscriptionsCallback = callback;
 };