notFound

The notFound function allows you to render the not-found file within a route segment as well as inject a <meta name="robots" content="noindex" /> tag.

notFound()

Invoking the notFound() function throws a NEXT_NOT_FOUND error and terminates rendering of the route segment in which it was thrown. Specifying a not-found file allows you to gracefully handle such errors by rendering a Not Found UI within the segment.

import { notFound } from 'next/navigation';
 
async function fetchUsers(id) {
  const res = await fetch('https://...');
  if (!res.ok) return undefined;
  return res.json();
}
 
export default async function Profile({ params }) {
  const user = await fetchUser(params.id);
 
  if (!user) {
    notFound();
  }
 
  // ...
}

Note: notFound() does not require you to use return notFound() due to using the TypeScript never type.