Hi Dennis Riungu, this is the best way that I found, to initialize firebase.

As official doc mentioned, centralizing all firebase related function into ONE single file, and export it.

export const DB = firebase.database()
export default firebase

This avoids creating multiple firebase.database() //or authinstances.

import * as firebase from 'firebase'
import 'firebase/auth/dist/index.cjs'
import 'firebase/firestore/dist/index.cjs'
import 'firebase/database/dist/index.cjs'
const config = {
   apiKey: 'foo',
   authDomain: 'foo',
   databaseURL: 'foo',
   projectId: 'foo',
   messagingSenderId: 'foo',
   storageBucket: 'foo',
}
if (!firebase.apps.length) {
   firebase.initializeApp(config)
}
export const auth = firebase.auth()
export const DB = firebase.database()
export default firebase