lib/request.js
function encodeUserAuth(user) {
  if (!user) {
    return null;
  }

  var token = user.token;
  if (token) {
    var sha1 = typeof token === 'object' ? token.sha1 : token;
    return 'token ' + sha1;
  }

  return 'Basic ' + base64.encode(user.username + ':' + user.password)
}
function encodeUserAuth(user) {
  if (!user) {
    return null;
  }

  var token = user.token;
  if (token) {
    var sha1 = typeof token === 'object' ? token.sha1 : token;
    return 'token ' + sha1;
  }

  return 'Basic ' + base64.encode(user.username + ':' + user.password)
}
Generates the authentication parameter for the user
Preference will be given to the token if it exists
@param user the use used for authentication. Requires token or username and password
@return {string|null} the properly formatted authentication string