Move JobQueue to be a module so that we can use it in preload

background.html

@@ -737,7 +737,6 @@
   <script type='text/javascript' src='js/models/blockedNumbers.js'></script>
   <script type='text/javascript' src='js/models/profile.js'></script>
   <script type='text/javascript' src='js/expiring_messages.js'></script>
-  <script type='text/javascript' src='js/job_queue.js'></script>
 
   <script type='text/javascript' src='js/chromium.js'></script>
   <script type='text/javascript' src='js/registration.js'></script>

js/job_queue.js

@@ -1,28 +0,0 @@
-/* eslint-disable more/no-then */
-
-// eslint-disable-next-line func-names
-(function() {
-  'use strict';
-
-  class JobQueue {
-    constructor() {
-      this.pending = Promise.resolve();
-    }
-
-    add(job) {
-      const previous = this.pending || Promise.resolve();
-      this.pending = previous.then(job, job);
-      const current = this.pending;
-
-      current.then(() => {
-        if (this.pending === current) {
-          delete this.pending;
-        }
-      });
-
-      return current;
-    }
-  }
-
-  window.JobQueue = JobQueue;
-})();

js/modules/job_queue.js

@@ -0,0 +1,24 @@
+/* eslint-disable more/no-then */
+class JobQueue {
+  constructor() {
+    this.pending = Promise.resolve();
+  }
+
+  add(job) {
+    const previous = this.pending || Promise.resolve();
+    this.pending = previous.then(job, job);
+    const current = this.pending;
+
+    current.then(() => {
+      if (this.pending === current) {
+        delete this.pending;
+      }
+    });
+
+    return current;
+  }
+}
+
+module.exports = {
+  JobQueue,
+}

preload.js

@@ -5,6 +5,7 @@ const electron = require('electron');
 const semver = require('semver');
 
 const { deferredToPromise } = require('./js/modules/deferred_to_promise');
+const { JobQueue } = require('./js/modules/job_queue');
 
 const { app } = electron.remote;
 const { clipboard } = electron;
@@ -31,6 +32,7 @@ window.getNodeVersion = () => config.node_version;
 window.getHostName = () => config.hostname;
 window.getServerTrustRoot = () => config.serverTrustRoot;
 window.isBehindProxy = () => Boolean(config.proxyUrl);
+window.JobQueue = JobQueue;
 
 window.isBeforeVersion = (toCheck, baseVersion) => {
   try {

test/index.html

@@ -373,7 +373,6 @@
   <script type='text/javascript' src='../js/expiring_messages.js' data-cover></script>
   <script type='text/javascript' src='../js/notifications.js' data-cover></script>
   <script type='text/javascript' src='../js/focus_listener.js'></script>
-  <script type='text/javascript' src='../js/job_queue.js'></script>
 
   <script type="text/javascript" src="../js/chromium.js" data-cover></script>