forked from sent/waves
53 lines
1.7 KiB
JavaScript
53 lines
1.7 KiB
JavaScript
const CACHE_NAME = 'offline';
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const OFFLINE_URL = 'offline.html';
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self.addEventListener('install', function(event) {
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console.log('[ServiceWorker] Install');
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event.waitUntil((async () => {
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const cache = await caches.open(CACHE_NAME);
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// Setting {cache: 'reload'} in the new request will ensure that the response
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// isn't fulfilled from the HTTP cache; i.e., it will be from the network.
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await cache.add(new Request(OFFLINE_URL, {cache: 'reload'}));
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})());
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self.skipWaiting();
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});
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self.addEventListener('activate', (event) => {
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console.log('[ServiceWorker] Activate');
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event.waitUntil((async () => {
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// Enable navigation preload if it's supported.
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// See https://developers.google.com/web/updates/2017/02/navigation-preload
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if ('navigationPreload' in self.registration) {
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await self.registration.navigationPreload.enable();
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}
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})());
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// Tell the active service worker to take control of the page immediately.
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self.clients.claim();
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});
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self.addEventListener('fetch', function(event) {
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// console.log('[Service Worker] Fetch', event.request.url);
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if (event.request.mode === 'navigate') {
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event.respondWith((async () => {
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try {
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const preloadResponse = await event.preloadResponse;
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if (preloadResponse) {
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return preloadResponse;
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}
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const networkResponse = await fetch(event.request);
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return networkResponse;
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} catch (error) {
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console.log('[Service Worker] Fetch failed; returning offline page instead.', error);
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const cache = await caches.open(CACHE_NAME);
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const cachedResponse = await cache.match(OFFLINE_URL);
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return cachedResponse;
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}
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})());
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}
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});
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