49 lines
2.2 KiB
JavaScript
49 lines
2.2 KiB
JavaScript
// Caution! Be sure you understand the caveats before using an up-front
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// preload strategy: https://googlechrome.github.io/samples/service-worker/prefetch/
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self.importScripts('./service-worker-assets.js');
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self.addEventListener('install', event => event.waitUntil(onInstall(event)));
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self.addEventListener('activate', event => event.waitUntil(onActivate(event)));
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self.addEventListener('fetch', event => event.respondWith(onFetch(event)));
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const cacheNamePrefix = 'offline-cache-';
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const cacheName = `${cacheNamePrefix}${self.assetsManifest.version}`;
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const offlineAssetsInclude = [/\.dll$/, /\.pdb$/, /\.wasm/, /\.html/, /\.js$/, /\.json$/, /\.css$/, /\.woff$/, /\.png$/, /\.jpe?g$/, /\.gif$/, /\.ico$/, /\.blat$/, /\.dat$/];
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const offlineAssetsExclude = [/^service-worker\.js$/];
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async function onInstall(event) {
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console.info('Service worker installing');
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// Fetch and cache all matching items from the assets manifest
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const assetsRequests = self.assetsManifest.assets
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.filter(asset => offlineAssetsInclude.some(pattern => pattern.test(asset.url)))
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.filter(asset => !offlineAssetsExclude.some(pattern => pattern.test(asset.url)))
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.map(asset => new Request(asset.url, {integrity: asset.hash, cache: 'no-cache'}));
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await caches.open(cacheName).then(cache => cache.addAll(assetsRequests));
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}
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async function onActivate(event) {
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console.info('Service worker activated');
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// Delete unused caches
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const cacheKeys = await caches.keys();
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await Promise.all(cacheKeys
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.filter(key => key.startsWith(cacheNamePrefix) && key !== cacheName)
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.map(key => caches.delete(key)));
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}
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async function onFetch(event) {
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let cachedResponse = null;
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if (event.request.method === 'GET') {
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// For all navigation requests, try to serve index.html from cache
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// If you need some routes to be uncached, add conditions here
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const shouldServeIndexHtml = event.request.mode === 'navigate';
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const request = shouldServeIndexHtml ? 'index.html' : event.request;
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const cache = await caches.open(cacheName);
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cachedResponse = await cache.match(request);
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}
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return cachedResponse || fetch(event.request);
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}
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