Basic way to initialize firebase for web

Firebase.js

import firebase from "firebase/app";
import "firebase/auth";
import "firebase/firestore";
import "firebase/functions";
import "firebase/storage";
import "firebase/messaging";
import "firebase/performance";

const config = {
  // set your config here
};

if (!firebase.apps.length) {
  firebase.initializeApp(config);
}

const auth = firebase.auth();
const storage = firebase.storage();
const functions = firebase.functions();
const firestore = firebase.firestore();
let messaging = null;
try {
  if (firebase.messaging.isSupported()) {
    messaging = firebase.messaging();
    messaging.usePublicVapidKey("your publicVapidKey here");
  }
} catch (e) {}
const perf = firebase.performance();

export { firebase, auth, storage, functions, firestore, messaging };