sw.js

const CACHE_NAME = 'qrtool-cache-v1';
const ASSETS = [
  './',
  './index.html',
  './style.css',
  './script.js',
  './qrcode.min.js',
  './manifest.json'
];
self.addEventListener('install', (e) => {
  e.waitUntil(caches.open(CACHE_NAME).then(cache => cache.addAll(ASSETS)).then(() => self.skipWaiting()));
});
self.addEventListener('activate', (e) => {
  e.waitUntil(caches.keys().then(keys => Promise.all(keys.map(k => k !== CACHE_NAME && caches.delete(k)))));
  self.clients.claim();
});
self.addEventListener('fetch', (e) => {
  e.respondWith(
    caches.match(e.request).then(res => res || fetch(e.request).then(resp => {
      const copy = resp.clone();
      caches.open(CACHE_NAME).then(c => c.put(e.request, copy)).catch(() => {});
      return resp;
    }).catch(() => res))
  );
});