Conditional custom hook data fetching in NextJS using SWR

User.tsx

/* eslint-disable @typescript-eslint/no-non-null-assertion */
import useSWR from "swr";
import { getCookie } from "cookies-next";
import type { User } from "../lib/interfaces";

export default function useUser() {
  const token = getCookie("token")?.toString();

  const { data, error, mutate } = useSWR<{
    user: User;
  }>(token ? [`${process.env.NEXT_PUBLIC_API_URL}/v1/me`, token] : null);

  return {
    user: data?.user,
    isLoading: !error && !data,
    error,
    mutate,
  };
}