withAuthUserTokenAPI.ts

import { withAuthUserTokenSSR, AuthAction, type AuthUser } from "next-firebase-auth";
import { NextApiRequest, NextApiResponse } from "next";

const checkServerSideAuth =
  typeof window !== "undefined"
    ? () => {} // "withAuthUserTokenSSR" can only be called server-side.
    : withAuthUserTokenSSR({
        whenAuthed: AuthAction.RENDER,
        whenUnauthed: AuthAction.REDIRECT_TO_LOGIN,
        authPageURL: "401",
      })(async ({ AuthUser }) => ({ AuthUser, props: {} }));

type AuthorizedApiHandler = (
  req: NextApiRequest,
  res: NextApiResponse,
  auth: AuthUser
) => Promise<void>;

export function withAuthUserTokenAPI(handler: AuthorizedApiHandler) {
  return async (req: NextApiRequest, res: NextApiResponse) => {
    // @ts-expect-error wrong typings in lib. remove expect-error if typings are correct now
    const { AuthUser, redirect } = await checkServerSideAuth({ req, res });
    if (redirect) {
      res.status(401).json({ ok: false, code: "unauthorized" });
      return;
    }
    return handler(req, res, AuthUser);
  };
}