Create sw.js

sw.js

@@ -0,0 +1,39 @@
+const CACHE = "tdhp-offline-v1";
+const ASSETS = [
+  "./",
+  "./index.html",
+  "./manifest.webmanifest",
+  "./tu_dien_hoang_phe_clean.json"
+];
+
+self.addEventListener("install", (event) => {
+  event.waitUntil(
+    caches.open(CACHE).then((c) => c.addAll(ASSETS)).then(() => self.skipWaiting())
+  );
+});
+
+self.addEventListener("activate", (event) => {
+  event.waitUntil(
+    caches.keys().then((keys) =>
+      Promise.all(keys.map((k) => (k === CACHE ? null : caches.delete(k))))
+    ).then(() => self.clients.claim())
+  );
+});
+
+self.addEventListener("fetch", (event) => {
+  const req = event.request;
+  event.respondWith(
+    caches.match(req).then((cached) => {
+      if (cached) return cached;
+      return fetch(req).then((fresh) => {
+        // cache lại các file tĩnh
+        const url = new URL(req.url);
+        if (ASSETS.includes(url.pathname.replace(/^\//, "./"))) {
+          const copy = fresh.clone();
+          caches.open(CACHE).then((c) => c.put(req, copy));
+        }
+        return fresh;
+      }).catch(() => cached);
+    })
+  );
+});