why getServerSideProps returns undefined

Question

Below is the component

function AsideLeft({initialAsideLeftHandler}: InferGetServerSidePropsType<typeof getServerSideProps>) {
  console.log(initialAsideLeftHandler)
  // ...
}

Below does not work and returns undefined

export const getServerSideProps:GetServerSideProps = async ({req}) => {
  const cookies = parseCookies(req);

  return {
    props: {
      initialAsideLeftHandler: cookies.asideLeftHandler
    }
  };
}

export default AsideLeft;

So I tried changing the return value to hardcoded object to see what would happen...but still, it returns undefined

export const getServerSideProps:GetServerSideProps = async () => {

  return {
    props: {
      initialAsideLeftHandler: {x:0,y:0}
    }
  };
}

export default AsideLeft;