What's the alternative to pages/_app.js in app router in NextJS? [duplicate]

Question

I am just starting with NextJS and there is a new router called app router. Now I have some tutorials using pages/_app.js from the NextJS page router. So, what's the corresponding file for that in the app router?

Answer 1

Inside app each folder represent a route segment. The very first folder i.e app itself represent the root route segment.

app/layout.js will now be the equivalent for _app.js in the new Next 13 app directory. Since, it is the one wrapping all route and sub routes of your whole app.