如果已经使用 Reactjs 登录，如何限制用户显示登录页面

Question

I am working on Reactjs and using nextjs framework, I am working on "Login Logout" module and i just want that if user already logged in ( email set in cookie) then he should redirect to "dashboard" page,How can i do this? I tried with following code but not working for me, giving me error ",Here is my current code

cookies returned from getServerSideProps Reason: undefined cannot be serialized as JSON

export async function getServerSideProps(context: { req: { headers: { cookies: any; }; }; }) {
    
  const cookies = context.req.headers.cookies;
  if (cookies && cookies.email) {
    // email is present in cookies, so redirect to /dashboard
    return {
      redirect: {
        destination: "/dashboard",
        statusCode: 302, // temporary redirect
      },
      props: {},
    };
  }
  
  return {
    props: {
      cookies,
    },
  };
}

Answer 1

When returning props.cookies from getServerSideProps , you are potentially returning the cookies as undefined . Use '' as the default value if missing.

You can do this:

  return {
    props: {
      cookies: cookies || '',
    },
  };

Answer 2

You need to parse the cookies and you can get the cookies on the request you don't need the header

const cookies = JSON.parse(context.req.cookies);
if(cookies.email !== undefined)...