When your app fetches data or performs operations that take time, showing a loading state improves user experience. Users don’t have to wait for seconds to see a blank screen that way; rather, they can see something, some skeletons or spinners, and know that they have to wait a bit to see what they’re looking for. To do that, especially for pages that do server-side rendering, you can use a special loading.js file that creates an automatic loading UI for your routes. When you add this file to a folder, it acts as a loading state while the page layout in that folder is being loaded. Did you think you would have to turn the whole component into the client side to show loadings using states? Nah, dummy.