Decides whether to use analytics after the analytics API has been given a chance to load.

index.html

@@ -222,24 +222,5 @@
             <a id="feedbackButton" data-container="body" data-toggle="popover" data-placement="right" data-i18n="[data-content]feedback"><i class="fa fa-heart"></i></a>
         </div>
     </div>
-    <script type="text/javascript">
-      if (!config.disableThirdPartyRequests) {
-        [
-          // FIXME The implementation provided by analytics.js starts an
-          // asynchronous download of the Google Analytics integration.
-          // Unfortunately, modules/statistics/AnalyticsAdapter.js has already
-          // made the decision to not use it at the current point of the
-          // execution and has initialized itself with the NoopAnalytics
-          // implementation i.e. the implementation of the method
-          // AnalyticsAdapter.sendEvent will amount to nothing.
-          'analytics.js?v=1'
-        ].forEach(function(extSrc) {
-          var extScript = document.createElement('script');
-          extScript.src = extSrc;
-          extScript.async = false;
-          document.head.appendChild(extScript);
-        });
-      }
-    </script>
   </body>
 </html>

modules/statistics/AnalyticsAdapter.js

@@ -1,15 +1,43 @@
+var ScriptUtil = require('../util/ScriptUtil');
+
+// Load the integration of a third-party analytics API such as Google Analytics.
+// Since we cannot guarantee the quality of the third-party service (e.g. their
+// server may take noticeably long time to respond), it is in our best interest
+// (in the sense that the intergration of the analytics API is important to us
+// but not enough to allow it to prevent people from joining a conference) to
+// download the API asynchronously. Additionally, Google Analytics will download
+// its implementation asynchronously anyway so it makes sense to append the
+// loading on our side rather than prepend it.
+if (config.disableThirdPartyRequests !== true) {
+    ScriptUtil.loadScript(
+            'analytics.js?v=1',
+            /* async */ true,
+            /* prepend */ false);
+}
+
+// NoopAnalytics
 function NoopAnalytics() {}
+
 NoopAnalytics.prototype.sendEvent = function () {};
 
+// AnalyticsAdapter
 function AnalyticsAdapter() {
-  var AnalyticsImpl = window.Analytics || NoopAnalytics;
-  this.analytics = new AnalyticsImpl();
+    // XXX Since we asynchronously load the integration of the analytics API and
+    // the analytics API may asynchronously load its implementation (e.g. Google
+    // Analytics), we cannot make the decision with respect to which analytics
+    // implementation we will use here and we have to postpone it i.e. we will
+    // make a lazy decision.
 }
 
 AnalyticsAdapter.prototype.sendEvent = function (action, data) {
+  var a = this.analytics;
+
+  if (a === null || typeof a === 'undefined') {
+      this.analytics = a = new (window.Analytics || NoopAnalytics)();
+  }
   try {
-    this.analytics.sendEvent.apply(this.analytics, arguments);
+      a.sendEvent.apply(a, arguments);
   } catch (ignored) {}
 };
 
-module.exports = new AnalyticsAdapter();
+module.exports = new AnalyticsAdapter();

modules/statistics/CallStats.js

@@ -1,6 +1,7 @@
 /* global config, $, APP, Strophe, callstats */
 
 var Settings = require('../settings/Settings');
+var ScriptUtil = require('../util/ScriptUtil');
 var jsSHA = require('jssha');
 var io = require('socket.io-client');
 var callStats = null;
@@ -49,15 +50,10 @@ if (_enabled) {
     // enough to allow it to prevent people from joining a conference) to (1)
     // start downloading their API as soon as possible and (2) do the
     // downloading asynchronously.
-    (function (d, src) {
-        var elementName = 'script';
-        var newScript = d.createElement(elementName);
-        var referenceNode = d.getElementsByTagName(elementName)[0];
-
-        newScript.async = true;
-        newScript.src = src;
-        referenceNode.parentNode.insertBefore(newScript, referenceNode);
-    })(document, 'https://api.callstats.io/static/callstats.min.js');
+    ScriptUtil.loadScript(
+            'https://api.callstats.io/static/callstats.min.js',
+            /* async */ true,
+            /* prepend */ true);
     // FIXME At the time of this writing, we hope that the callstats.io API will
     // have loaded by the time we needed it (i.e. CallStats.init is invoked).
 }

modules/util/ScriptUtil.js

@@ -0,0 +1,32 @@
+/**
+ * Implements utility functions which facilitate the dealing with scripts such
+ * as the download and execution of a JavaScript file.
+ */
+var ScriptUtil = {
+    /**
+     * Loads a script from a specific source.
+     *
+     * @param src the source from the which the script is to be (down)loaded
+     * @param async true to asynchronously load the script or false to
+     * synchronously load the script
+     * @param prepend true to schedule the loading of the script as soon as
+     * possible or false to schedule the loading of the script at the end of the
+     * scripts known at the time
+     */
+    loadScript: function (src, async, prepend) {
+        var d = document;
+        var tagName = 'script';
+        var script = d.createElement(tagName);
+        var referenceNode = d.getElementsByTagName(tagName)[0];
+
+        script.async = async;
+        script.src = src;
+        if (prepend) {
+            referenceNode.parentNode.insertBefore(script, referenceNode);
+        } else {
+            referenceNode.parentNode.appendChild(script);
+        }
+    },
+};
+
+module.exports = ScriptUtil;