https://fmnd.org/sw.js

1const CACHE_NAME = 'sw-v1';
2self.addEventListener('install', function(event) {
3    event.waitUntil(
4        caches.open(CACHE_NAME)
5        // .then(function(cache) {cache.addAll('./homepage.html')})
6    )
7})
8self.addEventListener('fetch', function (event) {
9    if (event.request.method === 'GET') {
10        event.respondWith(
11            caches.match(event.request)
12                .then(function(cached) {
13                    var networked = fetch(event.request)
14                        .then(function(response) {
15                            var cacheCopy = response.clone()
16                            // caches.open(CACHE_NAME)
17                                // .then(cache => cache.put(event.request, cacheCopy))
18                            return response;
19                        })
20                        .catch(function() {caches.match(offlinePage)});
21                    return cached || networked;
22                })
23        )
24    }
25    return;
26})