sw.js

const CACHE = 'phar-converter-v1';
const ASSETS = [
  './',
  './index.html',
  'https://cdn.jsdelivr.net/npm/jszip@3.10.1/dist/jszip.min.js',
  'https://cdn.jsdelivr.net/npm/pako@2.1.0/dist/pako.min.js'
];

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 => {
  e.respondWith(
    caches.match(e.request).then(r => r || fetch(e.request).then(resp => {
      if (resp.ok && e.request.url.startsWith('http')) {
        const clone = resp.clone();
        caches.open(CACHE).then(c => c.put(e.request, clone));
      }
      return resp;
    }).catch(() => caches.match('./index.html')))
  );
});