sw.js

/* Best Sub Bass Notes — service worker
   Strategy:
   - HTML/navigation: network-first (so returning visitors always get the latest),
     fall back to cache when offline.
   - Other assets: stale-while-revalidate (instant from cache, refreshed in background).
   Bump CACHE on every deploy that changes precached assets. */
const CACHE = "subbass-v3";
const ASSETS = [
  "./",
  "./index.html",
  "./manifest.webmanifest",
  "./favicon.svg",
  "./icon-192.png",
  "./icon-512.png",
  "./apple-touch-icon.png",
  "./og.png",
];

self.addEventListener("install", (e) => {
  e.waitUntil(
    caches.open(CACHE).then((c) => c.addAll(ASSETS)).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) => {
  const req = e.request;
  if (req.method !== "GET") return;

  const isHTML =
    req.mode === "navigate" ||
    req.destination === "document" ||
    (req.headers.get("accept") || "").includes("text/html");

  if (isHTML) {
    // network-first
    e.respondWith(
      fetch(req)
        .then((resp) => {
          const copy = resp.clone();
          caches.open(CACHE).then((c) => c.put(req, copy));
          return resp;
        })
        .catch(() => caches.match(req).then((r) => r || caches.match("./index.html")))
    );
    return;
  }

  // stale-while-revalidate for everything else
  e.respondWith(
    caches.match(req).then((cached) => {
      const network = fetch(req)
        .then((resp) => {
          const copy = resp.clone();
          caches.open(CACHE).then((c) => c.put(req, copy));
          return resp;
        })
        .catch(() => cached);
      return cached || network;
    })
  );
});