firebase-messaging-sw.js

importScripts('https://www.gstatic.com/firebasejs/7.23.0/firebase-app.js');
importScripts('https://www.gstatic.com/firebasejs/7.23.0/firebase-messaging.js');

var firebaseConfig = {
  apiKey: "API_KEY",
  authDomain: "AUTH_DOMAIN",
  databaseURL: "DB_URL",
  projectId: "PROJECT_ID",
  storageBucket: "STORAGE_BUCKET",
  messagingSenderId: "SENDER_ID",
  appId: "APP_ID"
};

// Initialize the Firebase app in the service worker by passing in
// your app's Firebase config object.
// https://firebase.google.com/docs/web/setup#config-object
firebase.initializeApp(firebaseConfig);

// Retrieve an instance of Firebase Messaging so that it can handle background
// messages.
const messaging = firebase.messaging();
messaging.setBackgroundMessageHandler(function (payload) {
    const promiseChain = clients
        .matchAll({
            type: "window",
            includeUncontrolled: true
        })
        .then(windowClients => {
            for (let i = 0; i < windowClients.length; i++) {
                const windowClient = windowClients[i];
                windowClient.postMessage(payload);
            }
        })
        .then(() => {
            return registration.showNotification("New Message");
        });
    return promiseChain;
});
self.addEventListener('notificationclick', function (event) {
    console.log('notification received: ', event)
});