1const PRECACHE = 'precache-20201021';
 2const RUNTIME = 'runtime';
 3
 4// A list of local resources we always want to be cached.
 5const PRECACHE_URLS = [
 6    '/',
 7    'script.js',
 8    'style.css',
 9    'https://cdn.jsdelivr.net/npm/lzma@2.3.2/src/lzma_worker.min.js',
10    'https://cdn.jsdelivr.net/combine/' +
11        'npm/lzma@2.3.2/src/lzma.min.js,' +
12        'npm/slim-select@1.25.0/dist/slimselect.min.js,' +
13        'npm/clipboard@2/dist/clipboard.min.js,' +
14        'npm/micromodal@0.4.6/dist/micromodal.min.js,' +
15        'npm/codemirror@5.58.1,' +
16        'npm/codemirror@5.58.1/addon/mode/loadmode.min.js,' +
17        'npm/codemirror@5.58.1/addon/mode/overlay.min.js,' +
18        'npm/codemirror@5.58.1/addon/mode/multiplex.min.js,' +
19        'npm/codemirror@5.58.1/addon/mode/simple.min.js,' +
20        'npm/codemirror@5.58.1/addon/scroll/simplescrollbars.js,' +
21        'npm/codemirror@5.58.1/mode/meta.min.js',
22    'https://cdn.jsdelivr.net/combine/' +
23        'npm/bootstrap@4.4.1/dist/css/bootstrap-grid.min.css,' +
24        'npm/slim-select@1.25.0/dist/slimselect.min.css,' +
25        'npm/codemirror@5.58.1/lib/codemirror.min.css,' +
26        'npm/codemirror@5.58.1/addon/scroll/simplescrollbars.css,' +
27        'npm/codemirror@5.58.1/theme/dracula.min.css,' +
28        'npm/microtip@0.2.2/microtip.min.css',
29    'https://cdn.jsdelivr.net/gh/JetBrains/JetBrainsMono/web/woff2/JetBrainsMono-Regular.woff2',
30    'https://cdn.jsdelivr.net/gh/JetBrains/JetBrainsMono/web/woff/JetBrainsMono-Regular.woff',
31    'https://cdn.jsdelivr.net/gh/JetBrains/JetBrainsMono/ttf/JetBrainsMono-Regular.ttf',
32    'https://fonts.gstatic.com/s/roboto/v20/KFOmCnqEu92Fr1Mu4mxK.woff2',
33];
34
35// The install handler takes care of precaching the resources we always need.
36self.addEventListener('install', (event) => {
37    event.waitUntil(
38        caches
39            .open(PRECACHE)
40            .then((cache) => cache.addAll(PRECACHE_URLS))
41            .then(self.skipWaiting())
42    );
43});
44
45// The activate handler takes care of cleaning up old caches.
46self.addEventListener('activate', (event) => {
47    const currentCaches = [PRECACHE, RUNTIME];
48    event.waitUntil(
49        caches
50            .keys()
51            .then((cacheNames) => {
52                return cacheNames.filter((cacheName) => !currentCaches.includes(cacheName));
53            })
54            .then((cachesToDelete) => {
55                return Promise.all(
56                    cachesToDelete.map((cacheToDelete) => {
57                        return caches.delete(cacheToDelete);
58                    })
59                );
60            })
61            .then(() => self.clients.claim())
62    );
63});
64
65// The fetch handler serves responses for same-origin resources from a cache.
66// If no response is found, it populates the runtime cache with the response
67// from the network before returning it to the page.
68self.addEventListener('fetch', (event) => {
69    if (!event.request.url.startsWith(self.location.origin) && !event.request.url.startsWith('https://cdn.jsdelivr.net')) {
70        return;
71    }
72    event.respondWith(
73        caches.match(event.request, { ignoreSearch: true }).then((cachedResponse) => {
74            if (cachedResponse) {
75                return cachedResponse;
76            }
77
78            return caches.open(RUNTIME).then((cache) => {
79                return fetch(event.request).then((response) => {
80                    // Put a copy of the response in the runtime cache.
81                    return cache.put(event.request, response.clone()).then(() => {
82                        return response;
83                    });
84                });
85            });
86        })
87    );
88});