optional integration of google analytics

firebase-init.js

@@ -9,5 +9,7 @@ const FIREBASE_INIT = {
   // Project Settings -> Cloud Messaging -> Web configuration -> Web Push certificates.
   // This value IS NOT included in the generated js config you get from
   // the firebase console. It needs to be added separately.
-  messagingVapidKey: "BOgQVPOMzIMXUpsYGpbVkZoEBc0ifKY_f2kSU5DNDGYI6i6CoKqqxDd7w7PJ3FaGRBgVGJffldETumOx831jl58"
+  messagingVapidKey: "BOgQVPOMzIMXUpsYGpbVkZoEBc0ifKY_f2kSU5DNDGYI6i6CoKqqxDd7w7PJ3FaGRBgVGJffldETumOx831jl58",
+  // Google analytics tag. Uncomment and use one you got from https://analytics.google.com/.
+  // measurementId: "G-ABCDEF1234"
 };

src/index.js

@@ -9,6 +9,19 @@ import { IntlProvider } from 'react-intl';
 import TinodeWeb from './views/tinode-web.jsx';
 import HashNavigation from './lib/navigation.js';
 
+// Insert google analytics script and tag if configured.
+if (FIREBASE_INIT && FIREBASE_INIT.measurementId) {
+  const head = document.getElementsByTagName('head')[0];
+  let script = document.createElement('script');
+  script.src = 'https://www.googletagmanager.com/gtag/js?id=' + FIREBASE_INIT.measurementId;
+  script.async = true;
+  head.prepend(script);
+  window.dataLayer = window.dataLayer || [];
+  function gtag(){dataLayer.push(arguments);}
+  gtag('js', new Date());
+  gtag('config', FIREBASE_INIT.measurementId);
+}
+
 // Allow loading translation strings for just one language.
 const messageLoader = {
   'de': _ => import('./i18n.min/de.json'),

umd/index.dev.js

@@ -21701,6 +21701,19 @@ __webpack_require__.r(__webpack_exports__);
 
 
 
+if (FIREBASE_INIT && FIREBASE_INIT.measurementId) {
+  const head = document.getElementsByTagName('head')[0];
+  let script = document.createElement('script');
+  script.src = 'https://www.googletagmanager.com/gtag/js?id=' + FIREBASE_INIT.measurementId;
+  script.async = true;
+  head.prepend(script);
+  window.dataLayer = window.dataLayer || [];
+  function gtag() {
+    dataLayer.push(arguments);
+  }
+  gtag('js', new Date());
+  gtag('config', FIREBASE_INIT.measurementId);
+}
 const messageLoader = {
   'de': _ => __webpack_require__.e(/*! import() */ "src_i18n_min_de_json").then(__webpack_require__.t.bind(__webpack_require__, /*! ./i18n.min/de.json */ "./src/i18n.min/de.json", 19)),
   'en': _ => __webpack_require__.e(/*! import() */ "src_i18n_min_en_json").then(__webpack_require__.t.bind(__webpack_require__, /*! ./i18n.min/en.json */ "./src/i18n.min/en.json", 19)),