Function loader

app/routes/index.tsx:20–31

({ request }: { request: Request })

type LoaderData = { toastMessage?: ToastMessage };

export async function loader({ request }: { request: Request }) {
  const cookie = request.headers.get("cookie");
  const session = await getSession(cookie);
  const toastMessage = session.get("toastMessage") as ToastMessage;

  return json(
    { toastMessage },
    {
      headers: { "Set-Cookie": await commitSession(session) },
    }
  );
}
export default function Index() {
  const { toastMessage } = useLoaderData<LoaderData>();