export { default } from "next-auth/middleware";
export const config = { matcher: ["/dashboard/:path*"] };

This is my current middleware

what do you want to do? Restrict logged in users from visiting sign in and sign up pages>?

yes

now i do it in the /signin and /signup page itself but im wondering if there is a better way in middleware

Yes in middleware you can check if the user has a session and if so then redirect them

You could do something like

//middleware.ts
import { NextResponse } from "next/server"
import { auth } from "@/app/auth"

// This function can be marked `async` if using `await` inside
export default auth((req) => {
   if (!req.auth) {
      return NextResponse.redirect(new URL("/signin", req.url))
   }
   // Check if signed in user tries to access sign in page 

    if (req.auth && req.nextUrl.pathname === "/signin") {
        return NextResponse.redirect(new URL("/", req.url))
    }
   return NextResponse.next()
})

// See "Matching Paths" below to learn more
export const config = {
   matcher: [
      /*
       * Protect every Route by default, expect:
       * - api (API routes)
       * - _next/static (static files)
       * - _next/image (image optimization files)
       * - favicon.ico (favicon file)
       */
      "/((?!api|_next/static|_next/image|favicon.ico).*)",
   ],
}

However you should not rely on middleware exclusively. From the authjs 5 docs, see image:

So you'd keep your your individual checks within the signin and signup page anyways. (Maybe not because you are checking for not authenticated. Might be an edge case)