Flutter WEB: Firebase: No Firebase App '[DEFAULT]' has been created

Issue

After adding these dependencies to my pubspec.yaml in my flutter WEB project

  firebase_auth: ^0.18.4+1
  cloud_firestore: ^0.14.4
  firebase_core: ^0.5.3

and these below to my web/index.html file

<script src="https://www.gstatic.com/firebasejs/8.2.1/firebase-app.js"></script>
  <script src="https://www.gstatic.com/firebasejs/8.2.1/firebase-auth.js"></script>
  <script src="https://www.gstatic.com/firebasejs/8.2.1/firebase-firestore.js"></script>

<script>
  // Your web app's Firebase configuration
  var firebaseConfig = {
    apiKey: "xxxxxxxxxxxxxxxxxxxxxxxx",
    authDomain: "xxxxxxxxxxxxxxxxxxx",
    projectId: "xxxxxxxxxxxxxxxxxxxx",
    storageBucket: "xxxxxxxxxxxxxxxxx",
    messagingSenderId: "xxxxxxxxxxxxxxxx",
    appId: "xxxxxxxxxxxxxxxxxxx"
  };
  // Initialize Firebase
  firebase.initializeApp(firebaseConfig);
</script>

when I try to rebuild the WEB app I get:

Firebase: No Firebase App ‘[DEFAULT]’ has been created – call Firebase App.initializeApp() (app/no-app).

any error related to this?
additional error:

FirebaseError: Firebase: No Firebase App '[DEFAULT]' has been created - call Firebase App.initializeApp() (app/no-app).
    at Object.f [as app] (https://www.gstatic.com/firebasejs/8.2.1/firebase-app.js:1:16867)
    at Object.app$ [as app] (http://localhost:40783/packages/firebase_core_web/src/interop/core.dart.lib.js:32:101)
    at initializeApp (http://localhost:40783/packages/firebase_core_web/firebase_core_web.dart.lib.js:81:25)
    at initializeApp.next (<anonymous>)
    at runBody (http://localhost:40783/dart_sdk.js:37976:34)
    at Object._async [as async] (http://localhost:40783/dart_sdk.js:38007:7)
    at firebase_core_web.FirebaseCoreWeb.new.initializeApp (http://localhost:40783/packages/firebase_core_web/firebase_core_web.dart.lib.js:74:20)
    at initializeApp (http://localhost:40783/packages/firebase_core/firebase_core.dart.lib.js:122:59)
    at initializeApp.next (<anonymous>)
    at runBody (http://localhost:40783/dart_sdk.js:37976:34)
    at Object._async [as async] (http://localhost:40783/dart_sdk.js:38007:7)
    at Function.initializeApp (http://localhost:40783/packages/firebase_core/firebase_core.dart.lib.js:121:20)
    at main$ (http://localhost:40783/packages/vibeland/widgets/subscription_widget.dart.lib.js:9807:36)
    at main$.next (<anonymous>)
    at runBody (http://localhost:40783/dart_sdk.js:37976:34)
    at Object._async [as async] (http://localhost:40783/dart_sdk.js:38007:7)
    at main$ (http://localhost:40783/packages/vibeland/widgets/subscription_widget.dart.lib.js:9805:18)
    at main (http://localhost:40783/web_entrypoint.dart.lib.js:34:27)
    at main.next (<anonymous>)
    at http://localhost:40783/dart_sdk.js:37956:33
    at _RootZone.runUnary (http://localhost:40783/dart_sdk.js:37810:58)
    at _FutureListener.thenAwait.handleValue (http://localhost:40783/dart_sdk.js:32771:29)
    at handleValueCallback (http://localhost:40783/dart_sdk.js:33319:49)
    at Function._propagateToListeners (http://localhost:40783/dart_sdk.js:33357:17)
    at async._AsyncCallbackEntry.new.callback (http://localhost:40783/dart_sdk.js:33082:27)
    at Object._microtaskLoop (http://localhost:40783/dart_sdk.js:38071:13)
    at _startMicrotaskLoop (http://localhost:40783/dart_sdk.js:38077:13)
    at http://localhost:40783/dart_sdk.js:33574:9

Solution

Initialize it in the main() method

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  runApp(MyApp());
}

Answered By – Zyair

Answer Checked By – Jay B. (FlutterFixes Admin)