sw.js

/* Offline cache so the installed app works without a network connection. */
const CACHE_NAME = "interval-timer-v1";
const ASSETS = ["./", "index.html", "manifest.webmanifest", "icon-180.png", "icon-512.png"];

self.addEventListener("install", (event) => {
  event.waitUntil(caches.open(CACHE_NAME).then((cache) => cache.addAll(ASSETS)));
  self.skipWaiting();
});

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

/* Network-first so updates are picked up when online, cache fallback offline. */
self.addEventListener("fetch", (event) => {
  if (event.request.method !== "GET") return;
  event.respondWith(
    fetch(event.request)
      .then((response) => {
        const copy = response.clone();
        caches.open(CACHE_NAME).then((cache) => cache.put(event.request, copy));
        return response;
      })
      .catch(() => caches.match(event.request, { ignoreSearch: true }))
  );
});