Serve cached legacy pages when response has HTTP error code

aleksis/core/vite.config.js

@@ -236,6 +236,16 @@ export default defineConfig({
                   "PWA-Is-Cacheable": "true",
                 },
               },
+              plugins: [
+                {
+                  fetchDidSucceed: async ({ request, response }) => {
+                    if (response.ok) {
+                      return response;
+                    }
+                    throw new Error(`${response.status} ${response.statusText}`);
+                  },
+                }
+              ],
             },
           },
           {