https://studydriver.com/sw.js

1importScripts('https://push.esputnik.com/service-worker.js');
2
3var ver = "v1.0";
4
5self.addEventListener('install', function(t) {
6    t.waitUntil(
7        caches.open(ver)
8            .then(function(cache) {
9                return cache.addAll([
10                    "/offline/"
11                ]);
12            })
13    );
14});
15
16self.addEventListener('activate', function(t) {
17    t.waitUntil(caches.keys().then(function(t) {
18        return Promise.all(t.map(function(t) {
19            if (-1 === ver.indexOf(t)) {
20                return caches.delete(t);
21            }
22        }))
23    }))
24});
25
26self.addEventListener('fetch', function(t) {
27    // Always bypass for range requests, due to browser bugs
28    if (t.request.headers.has('range')) return;
29    t.respondWith(
30        caches.match(t.request)
31            .then(function(response) {
32                return response || fetch(t.request);
33            })
34            .catch(function() {
35                return caches.match('/offline/');
36            })
37    );
38});