This was the source for my talk about React Summit 2023. In the talk, I show how to incrementally adopt to new App Router, and some of the benefits of using the new router versus the previous Pages Router approach.
This includes:
- Simplified data fetching
getInitialProps(Pages Router)getStaticProps/getServerSideProps(Pages Router)async/await(App Router)
- Colocating data fetching with components (React Server Components)
- Defining layouts through the file system (
layout.tsx) - Granular control over data freshness (
revalidatefor components) - Out-of-order streaming of data (Suspense for SSR)
- Simplified form submissions (Server Actions)
The data fetching methods in the Pages Router, like getServerSideProps, forward props to the default exported React component. This NEXT_DATA payload also includes rendering instructions.
Inside the App Router, there is no longer NEXT_DATA. Instead, the React Server Components payload includes the already rendered result, meaning no additional rendering work needs to be done on the client. This also means that the rendering instructions remain on the server, and just need to be "slotted" into the right place.
You'll also notice that in the App Router, the baseline client-side JavaScript of Next.js + React is smaller than the Pages Router.