Fix service worker for disabled docs

views/service-worker.js.erb

@@ -35,15 +35,25 @@ self.addEventListener('fetch', event => {
     const cachedResponse = await caches.match(event.request);
     if (cachedResponse) return cachedResponse;
 
+    try {
+      const response = await fetch(event.request);
+
+      if (!response.ok) {
+        throw new Error(`The HTTP request failed with status code ${response.status}`);
+      }
+
+      return response;
+    } catch (err) {
       const url = new URL(event.request.url);
 
       <%# Attempt to return the index page from the cache if the user is visiting a url like devdocs.io/offline or devdocs.io/javascript/global_objects/array/find %>
-    <%# The index page will handle the routing %>
+      <%# The index page will make sure the correct documentation or a proper offline page is shown  %>
       if (url.origin === location.origin && !url.pathname.includes('.')) {
         const cachedIndex = await caches.match('/');
         if (cachedIndex) return cachedIndex;
       }
 
-    return fetch(event.request);
+      throw err;
+    }
   })());
 });