firebase-messaging-sw.js

// public/

importScripts('https://www.gstatic.com/firebasejs/8.2.3/firebase-app.js');
importScripts('https://www.gstatic.com/firebasejs/8.2.3/firebase-messaging.js');

// Set Firebase configuration, once available
self.addEventListener('fetch', () => {
  const urlParams = new URLSearchParams(location.search);
  console.log('url', urlParams);
  self.firebaseConfig = Object.fromEntries(urlParams);
});

// "Default" Firebase configuration (prevents errors)
const defaultConfig = {
  apiKey: true,
  projectId: true,
  messagingSenderId: true,
  appId: true,
};

// Initialize Firebase app
firebase.initializeApp(self.firebaseConfig || defaultConfig);

const messaging = firebase.messaging();