Google app script for Twitter user information extraction

Twitter.gs

var options;

function setupTwitterAuth(consumerKey, consumerSecret){
  var oauthConfig = UrlFetchApp.addOAuthService('twitter');
  oauthConfig.setAccessTokenUrl('http://api.twitter.com/oauth/access_token');
  oauthConfig.setRequestTokenUrl('http://api.twitter.com/oauth/request_token');
  oauthConfig.setAuthorizationUrl('http://api.twitter.com/oauth/authorize');
  oauthConfig.setConsumerKey(consumerKey);
  oauthConfig.setConsumerSecret(consumerSecret);
  
  options = {
    'oAuthServiceName' : 'twitter',
    'oAuthUseToken' : 'always'
  };
}

function getTwitterUserJSON(screen_name){
  setupTwitterAuth("XXX","YYY")
  if(typeof(screen_name) == "undefined"){screen_name = '@twitter'}
  // API request documentation at https://dev.twitter.com/docs/api/1.1/get/users/show
  // API response documentation at https://dev.twitter.com/docs/platform-objects/users
  var url = 'http://api.twitter.com/1.1/users/show.json?screen_name='+screen_name.replace(/@/,'')
  var response = UrlFetchApp.fetch(url, options);
  return response.getContentText();
}

function extractFieldFromJSON(json,field){
  var data = JSON.parse(json);
  return ref(data,field)
}

// from http://stackoverflow.com/questions/10934664/convert-string-in-dot-notation-to-get-the-object-reference
function ref(obj, str) {
  str = str.split(".");
  for (var i = 0; i < str.length; i++)
    obj = obj[str[i]];
  return obj;
}