// Window const registration = await navigator.serviceWorker.register('/sw.js', {scope: '/'})

self.addEventListener('fetch', event => { return })

self.addEventListener('fetch', event => { event.respondWith(async function () { const req = event.request try { return fetch(req.clone()) } catch (err) { return caches.match(req) } }()) })

self.addEventListener('fetch', event => { event.respondWith(async function () { const req = event.request const res = await caches.match(req) if (res) return res return fetch(req.clone()) }()) })

async function findLatestCache (req) { const cacheNames = await caches.keys() for (const date of cacheNames.sort().reverse()) { const cache = await caches.open(date) const res = await cache.match(req, {ignoreSearch: true}) if (res) return res } return null }

let res try { // まずはnetworkから取得できるか試みる res = await fetch(req.clone()) } catch (err) { // 失敗したらCacheStorageから探す return findLatestApiCache(req) } // キャッシュを更新 updateApiCache(req, res.clone()) return res

const cache = await caches.open('images') const reqs = await cache.keys() // requestを1個ずつ削除すると、削除後にQuotaに即反映される for (const req of reqs) { await cache.delete(req.url) }

// Window async function prefetch (urls) { const {controller} = await navigator.serviceWorker return new Promise((resolve, reject) => { const channel = new MessageChannel() channel.port1.onmessage = event => { resolve(event.data) } controller.postMessage({ title: 'prefetch', body: {urls} }, [channel.port2]) }) }

self.addEventListener('message', event => { event.waitUntil(async function () { const {urls} = event.data // ここで各urlをfetchしてcacheに追加する // await fetch(new Request(url, {credentials: 'same-origin'})) event.ports[0].postMessage({title: 'prefetch'}) }()) })

navigator.serviceWorker.ready.then(function(registration) { registration.periodicSync.register({ tag: 'get-latest-news', minPeriod: 12 * 60 * 60 * 1000, powerState: 'avoid-draining', networkState: 'avoid-cellular' }).then(function(periodicSyncReg) { // success }, function() { // failure }) });

// Window const onClick = () => { return navigator.share({ title: document.title, url: location.href }) }