I'll create a Next.js application that fetches product details from the Fakestoreapi and renders them as a list. We'll use Server Components for data fetching and create a simple UI to display the products.

Let's create the application:

Now, let me explain the code and how it works:

1. In app/page.tsx, we create the main page component that renders the title and the ProductList component 1.

2. The components/product-list.tsx file contains the main logic for fetching and displaying the products 12:

   • We define an asynchronous getProducts function that fetches data from the Fakestoreapi.
   • The ProductList component is an async Server Component that awaits the getProducts function and renders the list of products.
   • We use the Image component from Next.js for optimized image loading and display 1.
   • The products are displayed in a responsive grid layout using Tailwind CSS classes.
3. The app/loading.tsx file defines a loading spinner that will be shown while the data is being fetched 23. This is automatically used by Next.js when the page is loading.
4. The app/error.tsx file defines an error boundary component that will be displayed if there's an error during data fetching or rendering 23. It includes a "Try again" button to reset the error state.
5. The types/product.ts file contains the TypeScript interface for the Product type, ensuring type safety throughout the application.

This application demonstrates several key features of Next.js 13 with the App Router:

• Server-side data fetching using async/await in Server Components 12.
• Automatic loading state handling with the loading.tsx file 23.
• Error handling with the error.tsx file 23.
• Optimized image loading with the Next.js Image component 1.
• Responsive design using Tailwind CSS.

To run this application, you would typically follow these steps:

1. Create a new Next.js project using create-next-app.
2. Replace the contents of the app folder with the provided files.
3. Create the components and types folders and add the respective files.
4. Run the development server using npm run dev or yarn dev.

The application will fetch product data from the Fakestoreapi and display it as a responsive grid of product cards. It includes loading and error states for a better user experience.