sw.js

// This is the service worker code that lives at the root (sw.js)

// You have to supply a name for your cache, this will
// allow us to remove an old one to avoid hitting disk
// space limits and displaying old resources
var cacheName = 'v1';

// Assets to cache
var assetsToCache = [
       '/',
	   '/manifest.json',
	   '/sw.js',
	   '/favicon.ico',
	   '/assets/css/style.css',
       '/index.php',
       '/assets/images/launcher-icon-1x.png',
       '/assets/images/launcher-icon-2x.png',
       '/assets/images/launcher-icon-3x.png',
       '/assets/images/launcher-icon-4x.png',
       '/assets/images/launcher-icon-256.png',
       '/assets/images/launcher-icon-384.png',
       '/assets/images/launcher-icon-512.png',
       '/assets/images/logo-black.png',
       '/assets/images/logo.svg'
];

self.addEventListener('sync', function(event) {
    if (event.registration.tag == "oneTimeSync") {
        console.dir(self.registration);
        console.log("One Time Sync Fired");
    }
});

self.addEventListener('install', function(event) {
  // waitUntil() ensures that the Service Worker will not
  // install until the code inside has successfully occurred
  event.waitUntil(
    // Create cache with the name supplied above and
    // return a promise for it
    caches.open(cacheName).then(function(cache) {
        // Important to `return` the promise here to have `skipWaiting()`
        // fire after the cache has been updated.
        return cache.addAll(assetsToCache);
    }).then(function() {
      // `skipWaiting()` forces the waiting ServiceWorker to become the
      // active ServiceWorker, triggering the `onactivate` event.
      // Together with `Clients.claim()` this allows a worker to take effect
      // immediately in the client(s).
      return self.skipWaiting();
    })
  );
});

// Activate event
// Be sure to call self.clients.claim()
self.addEventListener('activate', function(event) {
    // `claim()` sets this worker as the active worker for all clients that
    // match the workers scope and triggers an `oncontrollerchange` event for
    // the clients.
    return self.clients.claim();
});

self.addEventListener('fetch', function(event) {
  // Ignore non-get request like when accessing the admin panel
  if (event.request.method !== 'GET') { return; }
  // Don't try to handle non-secure assets because fetch will fail
  if (/http:/.test(event.request.url)) { return; }

  // Here's where we cache all the things!
  event.respondWith(
    // Open the cache created when install
    caches.open(cacheName).then(function(cache) {
      // Go to the network to ask for that resource
      return fetch(event.request).then(function(networkResponse) {
        // Add a copy of the response to the cache (updating the old version)
        cache.put(event.request, networkResponse.clone());
        // Respond with it
        return networkResponse;
      }).catch(function() {
        // If there is no internet connection, try to match the request
        // to some of our cached resources
        return cache.match(event.request);
      })
    })
  );
});

self.addEventListener('beforeinstallprompt', function(e)
{
	e.userChoice.then(function(choiceResult)
	{
		if(choiceResult.outcome == 'dismissed')
		{
			alert('User cancelled home screen install');
		}
		else
		{
			alert('User added to home screen');
		}
	});
});