rsnext/examples/middleware-matcher/middleware.js

import { NextResponse } from 'next/server'

export default function middleware(req) {
  const { pathname } = new URL(req.url)
  const response = NextResponse.next()
  response.headers.set(
    'set-cookie',
    `middleware-slug=${pathname.slice(1)}; Path=${pathname}`
  )
  return response
}

export const config = {
  matcher: [
    '/disclaimer', // match a single, specific page
    '/((?!public|static).*)', // match all paths not starting with 'public' or 'static'
  ],
}