sw.js

const cacheName = "GuessingGame"

self.addEventListener("install", function (event) {
  event.waitUntil(
    caches.open(cacheName).then(function (cache) {
      cache.addAll([
        './',
        './index.html',
        './style.css',
        './script',
        './manifest.webmanifest'
      ])
    })
  )
  return self.skipWaiting()
})

self.addEventListener('active', e => {
  self.clients.claim()
})

self.addEventListener("fetch", async e => {
  const req = e.request
  const url = new URL(req.url)

  if (url.login === location.origin) {
    e.respondWith(cacheFirst(req))
  } else {
    e.respondWith(networkAndCache(req))
  }
})

async function cacheFirst(req) {
  const cache = await caches.open(cacheName)
  const cached = await cache.match(req)

  return cached || fetch(req)
}

async function networkAndCache(req) {
  const cache = await caches.open(cacheName)
  try {
    const refresh = await fetch(req)
    await cache.put(req, refresh.clone())
    return refresh
  } catch (e) {
    const cached = await cache.match(req)
    return cached
  }
}