Firebase set up and config file to place inside your app folder to connect it to Firebase

firebase.js

// Firebase App (the core Firebase SDK) is always required and
// must be listed before other Firebase SDKs
import * as firebase from "firebase/app";

// Add the Firebase services that you want to use
// We only want to use Firebase Auth here
import "firebase/auth";

// Your app's Firebase configuration
var firebaseConfig = {
  apiKey: "YOUR_FIREBASE_API_KEY",
  authDomain: "YOUR_FIREBASE_AUTH_DOMAIN",
  databaseURL: "YOUR_FIREBASE_DB_URL",
  projectId: "YOUR_FIREBASE_PROJECT_ID",
  storageBucket: "",
  messagingSenderId: "YOUR_FIREBASE_MESSAGING_SENDER_ID",
  appId: "YOUR_FIREBASE_APP_ID"
};

// Initialize Firebase
firebase.initializeApp(firebaseConfig);

// Finally, export it to use it throughout your app
export default firebase;