React Router loader return value, which one to use?

[salicius]

Hi everyone i'm developing a react-router + react-query project and i'm making a loader for my page. But i don't quite understand some thing.
I load the data into the cache through the loader, but in the return value I put null (return null) or empty string (return ""), which is better? Or can I remove the return directly ?

export const loader =
  (queryClient) =>
  async () => {
    await queryClient.ensureQueryData(myDataQuery1());
    await queryClient.ensureQueryData(myDataQuery2());
    return ???;
  };