LinkedIn OAuth callback api function for NextJS, ReactJS

callback.js

export default async (req, res) => {
  const LINKEDIN_URL = "https://www.linkedin.com/oauth/v2/accessToken&grant_type=authorization_code&code=" + req.query.code + "redirect_uri=http://localhost:3000/api/callback&client_id=your_id is at https://www.linkedin.com/developers/apps/&client_secret=your_secret is at https://www.linkedin.com/developers/apps/";

  let tok;
  let resp = await fetch(LINKEDIN_URL, {
    method: 'POST',
    headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
  });

  if (resp.ok) tok = await resp.json();
  let { access_token, expires_in } = tok;
  let auth = 'Bearer ' + access_token;

  let u = {};
  let user = await fetch("https://api.linkedin.com/v2/me", {
    method: 'GET',
    headers: { 'Connection': 'Keep-Alive', 'Authorization': auth },
  });
  if (user.ok) u = await user.json();

  let em = {};
  let email = await fetch("https://api.linkedin.com/v2/emailAddress?q=members&projection=(elements*(handle~))", {
    method: 'GET',
    headers: { 'Connection': 'Keep-Alive', 'Authorization': auth },
  });
  if (email.ok) em = await email.json();
  u = {
    name: u.localizedFirstName + u.localizedLastName,
    email: em.elements[0]['handle~']['emailAddress'],
    password: access_token,
    expires_in: expires_in
  };

  res.status(200).json(u);
}