paliad/frontend/public/sw.js

// Paliad service worker — minimal cache-first for /assets/* and /icons/*,
// network-first for /api/*, network passthrough for everything else.
// Bumping CACHE_VERSION purges the previous cache on activation.
const CACHE_VERSION = "paliad-v1";
const STATIC_CACHE = `${CACHE_VERSION}-static`;

self.addEventListener("install", (event) => {
  // Activate the new SW as soon as it is installed; matters when
  // CACHE_VERSION changes so users don't keep stale assets.
  self.skipWaiting();
});

self.addEventListener("activate", (event) => {
  event.waitUntil(
    (async () => {
      const keys = await caches.keys();
      await Promise.all(
        keys
          .filter((k) => k !== STATIC_CACHE && k.startsWith("paliad-"))
          .map((k) => caches.delete(k)),
      );
      await self.clients.claim();
    })(),
  );
});

self.addEventListener("fetch", (event) => {
  const req = event.request;
  if (req.method !== "GET") return;

  const url = new URL(req.url);
  if (url.origin !== self.location.origin) return;

  if (url.pathname.startsWith("/assets/") || url.pathname.startsWith("/icons/")) {
    event.respondWith(cacheFirst(req));
    return;
  }

  if (url.pathname.startsWith("/api/")) {
    event.respondWith(networkFirst(req));
    return;
  }

  // HTML navigations + everything else: pass through to the network.
});

async function cacheFirst(req) {
  const cache = await caches.open(STATIC_CACHE);
  const cached = await cache.match(req);
  if (cached) return cached;
  try {
    const res = await fetch(req);
    if (res && res.ok) cache.put(req, res.clone());
    return res;
  } catch (err) {
    if (cached) return cached;
    throw err;
  }
}

async function networkFirst(req) {
  try {
    return await fetch(req);
  } catch (err) {
    const cache = await caches.open(STATIC_CACHE);
    const cached = await cache.match(req);
    if (cached) return cached;
    throw err;
  }
}