and here is the service worker code. importScripts('https://www.gstatic.com/firebasejs/8.10.1/firebase-app.js'); importScripts('https://www.gstatic.com/firebasejs/8.10.1/firebase-messaging.js'); // Initialize the Firebase app in the service worker const firebaseConfig = { apiKey: "AIzaSyAk9sULZ5s9B5Y8YxPhqXcWTeBrfCF-kTg", authDomain: "yum-alert-app.firebaseapp.com", projectId: "yum-alert-app", storageBucket: "yum-alert-app.firebasestorage.app", messagingSenderId: "1060315863763", appId: "1:1060315863763:web:af5158b631f329ceb9d226", measurementId: "G-RWHRBVVRYD" }; firebase.initializeApp(firebaseConfig); // Retrieve an instance of Firebase Messaging so that it can handle background messages. const messaging = firebase.messaging();