https://futuress.org/sw.js

1const PRECACHE = 'pre-cache'
2const RUNTIME = 'runtime-cache'
3
4// A list of local resources we always want to be cached.
5const PRECACHE_URLS = [
6  '/offline/'
7]
8
9const OFFLINE_URL = [
10  '/offline/'
11]
12
13// The install handler takes care of precaching the resources we always need.
14self.addEventListener('install', event => {
15  event.waitUntil(
16    caches.open(PRECACHE)
17      .then(cache => cache.addAll(PRECACHE_URLS))
18      .then(self.skipWaiting())
19  )
20})
21
22// The activate handler takes care of cleaning up old caches.
23self.addEventListener('activate', event => {
24  const currentCaches = [PRECACHE, RUNTIME]
25  event.waitUntil(
26    caches.keys().then(cacheNames => {
27      return cacheNames.filter(cacheName => !currentCaches.includes(cacheName))
28    }).then(cachesToDelete => {
29      return Promise.all(cachesToDelete.map(cacheToDelete => {
30        return caches.delete(cacheToDelete)
31      }))
32    }).then(() => self.clients.claim())
33  )
34})
35
36// The fetch handler serves responses for same-origin resources from a cache.
37// If no response is found, it populates the runtime cache with the response
38// from the network before returning it to the page.
39self.addEventListener('fetch', event => {
40  // Skip cross-origin requests, like those for Google Analytics.
41  if (event.request.url.startsWith(self.location.origin)) {
42    // Exclude certain paths from caching
43    if (event.request.url.includes('/ghost') || // Ghost Admin
44      event.request.url.includes('/signin') || // Signin Page
45      event.request.url.includes('/signup') || // Signin Page
46      event.request.url.includes('/account') || // Signin Page
47      event.request.url.includes('/members')) // Members
48    {
49      return false
50    }
51
52    event.respondWith(
53      caches.match(event.request).then(cachedResponse => {
54        return caches.open(RUNTIME).then(cache => {
55          return fetch(event.request).then(response => {
56            // Put a copy of the response in the runtime cache.
57            return cache.put(event.request, response.clone()).then(() => {
58              return response
59            })
60          }).catch(error => {
61            if (cachedResponse) {
62              return cachedResponse
63            } else {
64              // Check if the user is offline first and is trying to navigate to a web page
65              return caches.match(OFFLINE_URL)
66            }
67          })
68        })
69      })
70    )
71  }
72})