Use module pattern

js/cast.js

@@ -1,15 +1,14 @@
 /*global chrome*/
 /*jslint browser: true */
-var launchBtn, disabledBtn, stopBtn;
+var castModule = (function () {
-var session;
+    'use strict';
+    var launchBtn, disabledBtn, stopBtn, session;
 
     function receiverListener(e) {
-    'use strict';
         return (e === chrome.cast.ReceiverAvailability.AVAILABLE);
     }
 
     function onMediaDiscovered() {
-    'use strict';
         if (launchBtn) {
             stopBtn.classList.remove('cast_hidden');
             launchBtn.classList.add('cast_hidden');
@@ -17,20 +16,17 @@ function onMediaDiscovered() {
     }
 
     function onStopCast() {
-    'use strict';
         stopBtn.classList.add('cast_hidden');
         launchBtn.classList.remove('cast_hidden');
     }
 
     function updateListener() {
-    'use strict';
         if (session.status !== chrome.cast.SessionStatus.CONNECTED) {
             onStopCast();
         }
     }
 
     function sessionListener(e) {
-    'use strict';
         session = e;
         session.addMediaListener(onMediaDiscovered.bind(this, 'addMediaListener'));
         session.addUpdateListener(updateListener.bind(this));
@@ -40,34 +36,28 @@ function sessionListener(e) {
     }
 
     function stopCast() {
-    'use strict';
         session.stop(onStopCast);
     }
 
     function onMediaError() {
-    'use strict';
         stopCast();
     }
 
     function onRequestSessionSuccess(e) {
-    'use strict';
         session = e;
         var videoLink = document.getElementById('video_link'), videoURL = videoLink.dataset.video, mediaInfo = new chrome.cast.media.MediaInfo(videoURL, 'video/' + videoLink.dataset.ext), request = new chrome.cast.media.LoadRequest(mediaInfo);
         session.loadMedia(request, onMediaDiscovered.bind(this, 'loadMedia'), onMediaError);
     }
 
     function onLaunchError(e) {
-    'use strict';
         throw e.description;
     }
 
     function launchCast() {
-    'use strict';
         chrome.cast.requestSession(onRequestSessionSuccess, onLaunchError);
     }
 
     function onInitSuccess() {
-    'use strict';
         launchBtn = document.getElementById('cast_btn_launch');
         disabledBtn = document.getElementById('cast_disabled');
         stopBtn = document.getElementById('cast_btn_stop');
@@ -80,18 +70,15 @@ function onInitSuccess() {
     }
 
     function onError(e) {
-    'use strict';
         throw e.code;
     }
 
     function initializeCastApi() {
-    'use strict';
         var sessionRequest = new chrome.cast.SessionRequest(chrome.cast.media.DEFAULT_MEDIA_RECEIVER_APP_ID), apiConfig = new chrome.cast.ApiConfig(sessionRequest, sessionListener, receiverListener, chrome.cast.AutoJoinPolicy.ORIGIN_SCOPED);
         chrome.cast.initialize(apiConfig, onInitSuccess, onError);
     }
 
     function loadCastApi(loaded, errorInfo) {
-    'use strict';
         if (loaded) {
             initializeCastApi();
         } else {
@@ -99,13 +86,15 @@ function loadCastApi(loaded, errorInfo) {
         }
     }
 
-function initCast() {
+    return {
-    'use strict';
+        init: function () {
             var intro = document.getElementById('download_intro');
             if (intro) {
                 intro.insertAdjacentHTML('beforeend', '<img class="cast_icon" id="cast_disabled" src="img/ic_media_route_disabled_holo_light.png" alt="" title="Google Cast is not supported on this browser." /> <img class="cast_btn cast_hidden cast_icon" id="cast_btn_launch" src="img/ic_media_route_off_holo_light.png" title="Cast to ChromeCast" alt="Google Cast™" /> <img src="img/ic_media_route_on_holo_light.png" alt="Casting to ChromeCast…" title="Stop casting" id="cast_btn_stop" class="cast_btn cast_hidden cast_icon" />');
                 window.__onGCastApiAvailable = loadCastApi;
             }
         }
+    };
+}());
 
-window.addEventListener('load', initCast, false);
+window.addEventListener('load', castModule.init, false);