sgc-portal/mobile-src/public/firebase-messaging-sw.js

// this file must be placed in root

importScripts('https://www.gstatic.com/firebasejs/4.6.1/firebase-app.js');
importScripts('https://www.gstatic.com/firebasejs/4.6.1/firebase-messaging.js');

firebase.initializeApp({
    messagingSenderId: '813343642322',
});

self.addEventListener('push', function (event) {
    const payload = event.data.json();
    const title = payload.notification.title;
    const options = {
        body: payload.notification.body,
        icon: payload.notification.icon,
        data: payload.notification.click_action,
    };
    event.waitUntil(self.registration.showNotification(title, options));
});

self.addEventListener('notificationclick', function (event) {
    event.notification.close();
    event.waitUntil(clients.openWindow('/mobile/#' + (event.notification.data || '')));
});