how to Upload a download artifact using node fetch

[onemen]

i am confuse about the field

`

const formData = new FormData();

  formData.append("files", readStream);

  const body = formData;

  const headers = new Headers({

    Authorization: `Bearer ${access_token}`,

    "Content-Type": `multipart/form-data; boundary=${formData.getBoundary()}`,

  });

  fetch(url, {

    method: "POST",

    body,

    headers,

  })

`

i get:

`Response: 400 Bad Request
{"type": "error", "error": {"message": "files: This field is required.", "fields": {"files": ["This field is required."]}}}`

what is the proper Formdata ?