bgclock/public_html/sw.js

/* Cache-first: once installed the clock never touches the network again. */
const CACHE = "bgclock-v2";
const FILES = [
  "./",
  "./index.html",
  "./manifest.webmanifest",
  "./icon-192.png",
  "./icon-512.png",
  "./icon-maskable-512.png"
];

self.addEventListener("install", (e) => {
  e.waitUntil(caches.open(CACHE).then((c) => c.addAll(FILES)).then(() => self.skipWaiting()));
});

self.addEventListener("activate", (e) => {
  e.waitUntil(
    caches.keys()
      .then((keys) => Promise.all(keys.filter((k) => k !== CACHE).map((k) => caches.delete(k))))
      .then(() => self.clients.claim())
  );
});

self.addEventListener("fetch", (e) => {
  if (e.request.method !== "GET") return;
  e.respondWith(
    caches.match(e.request).then((hit) => hit || fetch(e.request).then((res) => {
      const copy = res.clone();
      caches.open(CACHE).then((c) => c.put(e.request, copy)).catch(() => {});
      return res;
    }).catch(() => caches.match("./index.html")))
  );
});