hallo knut

sw.js

@@ -0,0 +1,65 @@
+/* Offline app shell for the Interval Timer PWA. */
+
+const CACHE = 'interval-timer-v1';
+
+const ASSETS = [
+  './',
+  './index.html',
+  './styles.css',
+  './app.js',
+  './manifest.webmanifest',
+  './icons/icon-192.png',
+  './icons/icon-512.png',
+  './icons/icon-maskable-512.png',
+];
+
+self.addEventListener('install', (event) => {
+  event.waitUntil(
+    caches.open(CACHE)
+      .then((cache) => cache.addAll(ASSETS))
+      .then(() => self.skipWaiting())
+  );
+});
+
+self.addEventListener('activate', (event) => {
+  event.waitUntil(
+    caches.keys()
+      .then((keys) => Promise.all(keys.filter((k) => k !== CACHE).map((k) => caches.delete(k))))
+      .then(() => self.clients.claim())
+  );
+});
+
+self.addEventListener('fetch', (event) => {
+  const { request } = event;
+  if (request.method !== 'GET' || new URL(request.url).origin !== self.location.origin) return;
+
+  // Navigations: try the network, fall back to the cached shell when offline.
+  if (request.mode === 'navigate') {
+    event.respondWith(
+      fetch(request)
+        .then((response) => {
+          const copy = response.clone();
+          caches.open(CACHE).then((cache) => cache.put('./index.html', copy));
+          return response;
+        })
+        .catch(() => caches.match('./index.html'))
+    );
+    return;
+  }
+
+  // Everything else: cache first, refresh in the background.
+  event.respondWith(
+    caches.match(request).then((cached) => {
+      const network = fetch(request)
+        .then((response) => {
+          if (response && response.status === 200 && response.type === 'basic') {
+            const copy = response.clone();
+            caches.open(CACHE).then((cache) => cache.put(request, copy));
+          }
+          return response;
+        })
+        .catch(() => cached);
+      return cached || network;
+    })
+  );
+});