📦 Cache API — HTTP Responses Store Karo

// Cache open (ya create) karo
const cache = await caches.open("biryani-api-v1");

// Ek request/response add karo
await cache.add("/api/menu");

// Multiple requests add karo
await cache.addAll([
  "/api/menu",
  "/api/orders",
  "/static/menu.css",
  "/static/app.js"
]);

// Custom response add karo (put)
const response = new Response(JSON.stringify({ item: "Biryani", price: 450 }), {
  headers: { "Content-Type": "application/json" }
});
await cache.put("/api/custom", response);

// Cache se retrieve karo
const cachedResponse = await cache.match("/api/menu");
if (cachedResponse) {
  const data = await cachedResponse.json();
  console.log(data);
}

// Cache se delete karo
await cache.delete("/api/menu");

// Saare cached requests list karo
const keys = await cache.keys();
console.log("Cached URLs:", keys.map(k => k.url));

// Poori cache delete karo
await caches.delete("biryani-api-v1");

// Saare caches list karo
const cacheNames = await caches.keys();
console.log("All caches:", cacheNames);

// ─── Service Worker Pattern (offline support) ───
// service-worker.js mein:
self.addEventListener("fetch", (event) => {
  event.respondWith(
    caches.match(event.request).then(cached => {
      return cached || fetch(event.request).then(response => {
        if (response.ok) {
          const clone = response.clone();
          caches.open("dynamic-v1").then(cache => cache.put(event.request, clone));
        }
        return response;
      });
    }).catch(() => {
      return caches.match("/offline.html");
    })
  );
});