firebase.js

import { initializeApp } from 'firebase/app';
import { initializeFirestore } from 'firebase/firestore'
import { getAuth } from "firebase/auth";

const firebaseConfig = {
    apiKey: "<your_project_key>",
    authDomain: "<your_project_key>",
    projectId: "<your_project_key>",
    storageBucket: "<your_project_key>",
    messagingSenderId: "<your_project_key>",
    appId: "<your_project_key>",
    measurementId: "<your_project_key>"
};
// app instance
const app = initializeApp(firebaseConfig);

// auth instance
const auth = getAuth(app);

// db instance (firestore)
const db = initializeFirestore(app, {experimentalForceLongPolling: true});

// using app and db in other files
export {
    app,
    db,
    auth
}