Edit

[EDIT] FILE: firebase-messaging-sw.js

importScripts('https://www.gstatic.com/firebasejs/7.2.1/firebase-app.js');
importScripts('https://www.gstatic.com/firebasejs/7.2.1/firebase-messaging.js');
// For an optimal experience using Cloud Messaging, also add the Firebase SDK for Analytics. 
importScripts('https://www.gstatic.com/firebasejs/7.2.1/firebase-analytics.js');

// Initialize the Firebase app in the service worker by passing in the
// messagingSenderId.
firebase.initializeApp({
  'messagingSenderId': '665549591775'
});

// Retrieve an instance of Firebase Messaging so that it can handle background
// messages.
const messaging = firebase.messaging();

messaging.setBackgroundMessageHandler(function(payload) {
  console.log('[push_notification/firebase-messaging-sw.js] Received background message ', payload);
  // Customize notification here
  const notificationTitle = 'Background Message Title';
  const notificationOptions = {
    body: 'Background Message body.',
    icon: '/itwonders-web-logo.png'
  };

return self.registration.showNotification(notificationTitle,
      notificationOptions);
});

CANCEL