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// Some user agents only offer app installation if there is a SW and it handles
// offline requests.
const cacheVersion = '1.0';
const CACHE_NAME = `cache-v${cacheVersion}`;
// The resources cached by this service worker.
// Only resources on the primary origin are cached. The target pages are loaded
// on scope-extension origins and cannot be served by this service worker.
const resources = [
'scope_extensions-member-service-worker.js',
'scope_extensions-member-manual.sub.tentative.html',
'resources/icon.png',
];
// Load all resources for this service worker.
const precache = async () => {
const cache = await caches.open(CACHE_NAME);
await cache.addAll(resources);
};
// Get a resource from the cache.
const fromCache = async request => {
const cache = await caches.open(CACHE_NAME);
return await cache.match(request.url);
};
// Attempt to get resources from the network first, fallback to the cache if
// we're offline.
const networkFallbackToCache = async request => {
try {
const response = await fetch(request);
if (response.ok)
return response;
} catch {
// A cached response may still make the installed app usable offline.
}
return await fromCache(request) || Response.error();
};
// When we have a new service worker, update the caches and swap immediately.
self.addEventListener('install', e => {
e.waitUntil(precache().then(() => self.skipWaiting()));
});
// Claim existing clients.
self.addEventListener('activate', e => {
e.waitUntil(self.clients.claim());
});
// When a resource needs to be fetched, check whether it is contained in the
// cache and return the cached version, otherwise get it from the network.
self.addEventListener('fetch', e => {
e.respondWith(networkFallbackToCache(e.request));
});