network first strategy with cache update

wwwroot/service-worker.js

     self.clients.claim();
 });
 
-// fetch events (Network first strategy, no cache update after install)
+// fetch events (Network first strategy, cache update after fetch)
 self.addEventListener('fetch', function (event) {
     event.respondWith(fromNetwork(event.request, 30000).catch(function () {
         return fromCache(event.request);
         var timeoutId = setTimeout(reject, timeout);
         fetch(request).then(function (response) {
             clearTimeout(timeoutId);
+            var responseClone = response.clone();
+            caches.open(staticCacheName).then(function (cache) {
+                cache.put(request, responseClone);
+            });
             fulfill(response);
         }, reject);
     });