Drive API Write File Javascript

DriveAPIRenameFile.js

const DriveRenameUrl      = 'https://content.googleapis.com/drive/v3/files/';
// rename file - fetch
fetch(
    DriveRenameUrl + fileId + '?alt=json',                            
    {
        method: 'PATCH',
        headers: {
            Authorization: 'Bearer ' + token,
            'Accept': 'application/json',
            'Content-Type': 'application/json'
        },
        body: JSON.stringify({
            'name': FilenameString
        })
    }
).then(response => response.text()
).then(function(respText) {
    console.log(respText);
}).catch(function(error) {
    console.log(error);
});