self.addEventListener('fetch', event => { event.respondWith(async function () { // ... }()) })

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

self.addEventListener('fetch', event => { const { method, url } = event.request if (method !== 'POST') return if (new URL(url).pathname === '/serviceworker-upload') { event.respondWith((async () => { // POSTリクエストを発行する })()) } })

{ ... "share_target": { "action": "/serviceworker-upload", "method": "POST", "enctype": "multipart/form-data", "params": { ... } } }

self.addEventListener('fetch', event => { event.respondWith(async function () { const req = event.request try { // まずはnetworkから取得できるか試みる return fetch(req.clone()) } catch (err) { // 失敗したらCacheStorageから探す 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()) }()) })

const options = Object.create(null) if (req.mode !== 'navigate') options.mode = req.mode if (req.credentials) options.credentials = req.credentials if (req.redirect) options.redirect = req.redirect return fetch(req, options)

res.ok == false res.status == 0 res.body == null

self.addEventListener('fetch', event => { event.respondWith((async function () { // キャッシュを探して... // ... // 最終的にnetworkから取得 return fetch(req.clone()) })()) })

self.addEventListener('fetch', event => { if (req.destination === 'video') return event.respondWith((async function () { // ... })()) })

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 // 各urlをfetchして cache.put() する Promise.all(urls.map(async url => { const response = await fetch(url) // cache "prefetch" と "api" を更新する }) event.ports[0].postMessage({ title: 'prefetch' }) }()) })

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 }

const cache = await caches.open('images') const reqs = await cache.keys() // requestを1個ずつ削除する for (const req of reqs) { await cache.delete(req.url) } // 仕上げにcache objectを削除 caches.delete("images")