sune/docs/sw.js

const DB_NAME = "sune-sw-db";
const STORE = "kv";
const KEY = "lastSession";
function idbOpen() {
  return new Promise((resolve, reject) => {
    const r = indexedDB.open(DB_NAME, 1);
    r.onupgradeneeded = () => {
      r.result.createObjectStore(STORE);
    };
    r.onsuccess = () => resolve(r.result);
    r.onerror = () => reject(r.error || new Error("idb open error"));
  });
}
function idbGet(key) {
  return idbOpen().then((db) => new Promise((res, rej) => {
    const tx = db.transaction(STORE, "readonly");
    const req = tx.objectStore(STORE).get(key);
    req.onsuccess = () => res(req.result);
    req.onerror = () => rej(req.error);
  }));
}
function idbSet(key, val) {
  return idbOpen().then((db) => new Promise((res, rej) => {
    const tx = db.transaction(STORE, "readwrite");
    const req = tx.objectStore(STORE).put(val, key);
    req.onsuccess = () => res(true);
    req.onerror = () => rej(req.error);
  }));
}
const SESSION_ID = Date.now().toString(36) + "-" + Math.floor(Math.random() * 1e9).toString(36);
const STARTED_AT = Date.now();
self.addEventListener("install", (ev) => {
  self.skipWaiting();
});
self.addEventListener("activate", (ev) => {
  ev.waitUntil(self.clients.claim());
});
self.addEventListener("message", (ev) => {
  const data = ev.data || {};
  if (data.type !== "PING") return;
  const respond = async () => {
    try {
      const last = await idbGet(KEY);
      const restarted = !!last && last !== SESSION_ID;
      await idbSet(KEY, SESSION_ID);
      const payload = {
        type: "PONG",
        ts: Date.now(),
        sessionId: SESSION_ID,
        lastSessionId: last || null,
        restarted,
        uptimeMs: Date.now() - STARTED_AT,
        ok: true
      };
      if (ev.ports && ev.ports[0]) {
        ev.ports[0].postMessage(payload);
      } else {
        const clients = await self.clients.matchAll({ includeUncontrolled: true });
        clients.forEach((c) => c.postMessage(payload));
      }
    } catch (err) {
      const errPayload = { type: "PONG", ok: false, error: String(err), ts: Date.now() };
      if (ev.ports && ev.ports[0]) ev.ports[0].postMessage(errPayload);
    }
  };
  if (ev.waitUntil) ev.waitUntil(Promise.resolve(respond()));
  else respond();
});