sw.js

const CACHE = 'dzikr-v1';

const PRECACHE = [
  '/',
  '/index.html',
  '/css/style.css',
  '/js/data.js',
  '/js/app.js',
  '/manifest.json',
  '/icons/icon.svg',
  '/icons/icon-192.png',
  '/icons/icon-512.png'
];

self.addEventListener('install', e => {
  e.waitUntil(
    caches.open(CACHE).then(c => c.addAll(PRECACHE)).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 => {
  // Let cross-origin requests (Google Fonts, sunnah.com links) pass through untouched
  if (new URL(e.request.url).origin !== self.location.origin) return;

  e.respondWith(
    caches.match(e.request).then(cached => {
      if (cached) return cached;
      return fetch(e.request).then(res => {
        if (!res || res.status !== 200 || res.type !== 'basic') return res;
        const clone = res.clone();
        caches.open(CACHE).then(c => c.put(e.request, clone));
        return res;
      });
    })
  );
});