Error: No Firebase App '[DEFAULT]' has been created - call Firebase App.initializeApp()

Question

I have a firebase database linked up to two apps, one being an iOS app and another being a web app coded in node.js which is a basic algorithm that sets data to the database

Answer 1

Flutter web

For me the error occurred when I run my application in "release" mode

flutter run -d chrome --release

and when I deployed the application on the Firebase hosting

firebase deploy

Solution

Since I initialized Firebase in the index.html, I had to change the implementation order of firebase and main.dart.js

<script>
  var firebaseConfig = {
  apiKey: "xxxxxxxxxxxxxxxxxxxxxx",
  authDomain: "xxxxxxxxxxx.firebaseapp.com",
  databaseURL: "https://xxxxxxxxxx.firebaseio.com",
  projectId: "xxxxxxxxxxx",
  storageBucket: "xxxxxxxx.appspot.com",
  messagingSenderId: "xxxxxxxxxxx",
  appId: "1:xxxxxxxxxx:web:xxxxxxxxxxxxx",
  measurementId: "G-xxxxxxxxx"
  };
  // Initialize Firebase
  firebase.initializeApp(firebaseConfig);
  firebase.analytics();
</script>

//moved below firebase init
<script src="main.dart.js" type="application/javascript"></script>

Answer 2

Complete tutorial source link

Use initializeApp before @NgModule

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { RouteReuseStrategy } from '@angular/router';

import { IonicModule, IonicRouteStrategy } from '@ionic/angular';
import { SplashScreen } from '@ionic-native/splash-screen/ngx';
import { StatusBar } from '@ionic-native/status-bar/ngx';

import { AppComponent } from './app.component';
import { AppRoutingModule } from './app-routing.module';
import { environment } from 'src/environments/environment';
import { AuthenticateService } from './services/authentication.service';
import { AngularFireAuthModule } from '@angular/fire/auth';

import * as firebase from 'firebase';

firebase.initializeApp(environment.firebase);

@NgModule({
  declarations: [AppComponent],
  entryComponents: [],
  imports: [
    BrowserModule, 
    IonicModule.forRoot(), 
    AppRoutingModule,
    AngularFireAuthModule
  ],
  providers: [
    StatusBar,
    SplashScreen,
    AuthenticateService,
    { provide: RouteReuseStrategy, useClass: IonicRouteStrategy }
  ],
  bootstrap: [AppComponent]
})
export class AppModule {}

Answer 3

I had a similar issue following Firebase's online guide found here.

The section heading "Initialize multiple apps" is misleading as the first example under this heading actually demonstrates how to initialize a single, default app. Here's said example:

// Initialize the default app
var defaultApp = admin.initializeApp(defaultAppConfig);

console.log(defaultApp.name);  // "[DEFAULT]"

// Retrieve services via the defaultApp variable...
var defaultAuth = defaultApp.auth();
var defaultDatabase = defaultApp.database();

// ... or use the equivalent shorthand notation
defaultAuth = admin.auth();
defaultDatabase = admin.database();

If you are migrating from the previous 2.x SDK you will have to update the way you access the database as shown above, or you will get the, No Firebase App '[DEFAULT]' error.

Google has better documentation at the following:

1. INITIALIZE: https://firebase.google.com/docs/database/admin/start

2. SAVE: https://firebase.google.com/docs/database/admin/save-data

3. RETRIEVE: https://firebase.google.com/docs/database/admin/retrieve-data