appengine/gophers: alert if Firebase JS not setup
<!-- [START init_firebase] -->
<!-- *******************************************************************************************
* TODO(DEVELOPER): Paste the initialization snippet from:
- * Firebase Console > Overview > Add Firebase to your web app.
+ * http://console.firebase.google.com > Overview > Add Firebase to your web app.
***************************************************************************************** -->
<!-- [END init_firebase] -->
-
+ <script>
+ if (typeof firebase === 'undefined') {
+ const msg = "Please paste the Firebase initialization snippet into index.html. See https://console.firebase.google.com > Overview > Add Firebase to your web app.";
+ console.log(msg);
+ alert(msg);
+ }
+ </script>
<!-- [START include_firebaseui] -->
<script src="https://cdn.firebase.com/libs/firebaseui/2.6.2/firebaseui.js"></script>
<link type="text/css" rel="stylesheet" href="https://cdn.firebase.com/libs/firebaseui/2.6.2/firebaseui.css" />
