sw.js

const cacheName 	= 'app-shell';
const filesToCache 	= [
	'/es6-todo-app/assets/todo.css',
	'/es6-todo-app/assets/todo.js',
	'/es6-todo-app/index.html',
	'/es6-todo-app/sw.js',
	'/es6-todo-app/'
];

self.addEventListener('install', function(e) {
	console.log('[ServiceWorker] Install');
	e.waitUntil(
		caches.open(cacheName).then(function(cache) {
			console.log('[ServiceWorker] Caching app shell');
			return cache.addAll(filesToCache);
		})
	);
})

self.addEventListener('activate', function(e) {
	console.log('[ServiceWorker] Activate');
	e.waitUntil(
		caches.keys().then(function(keyList) {
			return Promise.all(keyList.map(function(key) {
				if (key !== cacheName) {
					console.log('[ServiceWorker] Removing old cache', key);
					return caches.delete(key);
				}
			}));
		})
	);
	return self.clients.claim();
});

self.addEventListener('fetch', function(e) {
	console.log('[ServiceWorker] Fetch', e.request.url);
	e.respondWith(
		caches.match(e.request).then(function(response) {
			return response || fetch(e.request);
		})
	);
});