props are returned as string instead of object-CodePudding

I'm currently implementing user authentication on my website, and I'm trying to restrict access to the login and signup pages if the user is logged in. To do so, I am implementing this getServerSideProps to redirect the user if they're logged in:

export async function getServerSideProps(context) {
  if (context.req.cookies.user) {
    return {
      redirect: {
        destination: '/',
        permanent: true,
      },
    }
  }
  return {}
}

If I return an empty object ({}), next gives me this error:

Reason: Props must be returned as a plain object from getServerSideProps: `{ props: { ... } }` (received: `[object Array]`).

If instead of returning {}, I return

{
  props: {}
}

the code works all right. Does anyone know why this is happening?

I'm using a custom _app.jsx file.

In the documentation, it's clearly mentioned that the props argument is optional:

CodePudding user response：

This is actually intended. If you were using TypeScript, return {} would have thrown you error as GetServerSidePropsResult is defined like this here:

export type GetServerSidePropsResult<P> =
  | { props: P | Promise<P> }
  | { redirect: Redirect }
  | { notFound: true }

It means that any one of props, redirect, notFound needs to be present in the returned object. Perhaps you can create an issue at their GitHub (and maybe a PR) to fix the documentation.

CodePudding user response：

As mentioned by @tromgy, it was just the documentation that is unclear.