sw.js

// use a cacheName for cache versioning
var cacheName = 'v1::static';

// during the install phase you usually want to cache static assets
self.addEventListener('install', function(e) {
    // once the SW is installed, go ahead and fetch the resources to make this work offline
    e.waitUntil(
        caches.open(cacheName).then(function(cache) {
            return cache.addAll([
                './css/style.css',
                './js/build/script.min.js',
                './js/build/vendor.min.js',
                './js/vendor/modernizr.min.js',
                './js/vendor/jquery.min.js',
                'https://fonts.googleapis.com/css?family=Roboto:300,600,300italic,600italic'
            ]).then(function() {
                self.skipWaiting();
            });
        })
    );
});

// when the browser fetches a url
self.addEventListener('fetch', function(event) {
    // either respond with the cached object or go ahead and fetch the actual url
    event.respondWith(
        caches.match(event.request).then(function(response) {
            if (response) {
                console.log('Retrieved from cache', response.url);
                // retrieve from cache
                return response;
            }
            // fetch as normal
            return fetch(event.request);
        })
    );
});

self.addEventListener('push', function(event) {
    console.log('Received a push message');

    var title = 'New message.'; 
    var body = 'You have received a new message.';
    var icon = './launcher-icon-8x.png';
    var tag = 'simple-push-demo-notification-tag';

    event.waitUntil(
        self.registration.showNotification(title, {
            body: body,
            icon: icon,
            tag: tag
        })
    );
});