https://www.opovo.com.br/firebase-messaging-sw.js

1importScripts('https://www.gstatic.com/firebasejs/3.9.0/firebase-app.js');
2importScripts('https://www.gstatic.com/firebasejs/3.9.0/firebase-messaging.js');
3
4// Initialize the Firebase app in the service worker by passing in the
5// messagingSenderId.
6firebase.initializeApp({
7  'messagingSenderId': '620431458743'
8});
9
10// Retrieve an instance of Firebase Messaging so that it can handle background
11// messages.
12const messaging = firebase.messaging();
13
14messaging.setBackgroundMessageHandler(function(payload) {
15  var notification = JSON.parse(payload.data.notification);
16  
17  // Customize notification here
18  const notificationTitle = notification.title;
19  const notificationOptions = {
20    body: notification.body,
21    icon:notification.icon,
22    click_action: notification.click_action
23  };
24
25  self.addEventListener('notificationclick', function(event) {
26    event.notification.close();
27    event.waitUntil(self.clients.openWindow(notification.click_action));
28  });
29
30  return self.registration.showNotification(notificationTitle,
31      notificationOptions);
32});