Trying to read request but getting Request {}

I am trying to work with an api but I can’t get the result of the request:

async function user(id) {
  let req = new Request(`https://api.clashroyale.com/v1/players/%23${id}`)
  req.method = "GET";
  req.headers = {"authorization": `Bearer ${token}`}
  let json = await req
  console.log(json)
}

It returns

Request {}

How can I get the content of the response?