const url ='http://sample.example.file.doc'
const authHeader ="Bearer 6Q************" 

const options = {
  headers: {
    Authorization: authHeader
  }
};
 fetch(url, options)
  .then( res => res.blob() )
  .then( blob => {
    var file = window.URL.createObjectURL(blob);
    window.location.assign(file);
  });

fetch("https://free-nba.p.rapidapi.com/teams?page=0", {
	"method": "GET",
	"headers": {
		"x-rapidapi-host": "free-nba.p.rapidapi.com",
		"x-rapidapi-key": "d1e022a733msh4e2c4a1ea244bf9p1a3971jsnea127bfc9297"
	}
})
.then((response) => {
  return response.json() // << This is the problem
})
.then((responseData) => { // responseData = undefined
  console.log(responseData.data);
 
})
.catch(err => {
	console.error(err);
});