Google Apps Script shim to replace UrlShortener calls with a Bit.ly version

UrlShortener.gs

// https://addyosmani.com/blog/essential-js-namespacing/
// extend.js
// written by andrew dupont, optimized by addy osmani
function extend(destination, source) {
    var toString = Object.prototype.toString,
        objTest = toString.call({});
    for (var property in source) {
        if (source[property] && objTest == toString.call(source[property])) {
            destination[property] = destination[property] || {};
            extend(destination[property], source[property]);
        } else {
            destination[property] = source[property];
        }
    }
    return destination;
};

// replacement for UrlShortener
var UrlShortener = UrlShortener || {};
extend(UrlShortener, {
  Util:{
    getCachedProperty: function (key){
      var cache = CacheService.getScriptCache()
      var value = cache.get(key)
      if (!value){
        var value = PropertiesService.getScriptProperties().getProperty(key);
        cache.put(key, value, 86400);
      }
      return value;
    },
    setToken: function(token){
      PropertiesService.getScriptProperties().setProperty('BITLY_TOKEN', token)
    },
    setGUID: function(guid){
      PropertiesService.getScriptProperties().setProperty('BITLY_GUID', token)
    },
    CALL_: function(path,options){
      var fetchOptions = {method:"",muteHttpExceptions:true, contentType:"application/json", headers:{Authorization:"Bearer "+UrlShortener.Util.getCachedProperty('BITLY_TOKEN')}};
      var url = 'https://api-ssl.bitly.com/v4' + path;
      for(option in options){
        fetchOptions[option] = options[option];
      }
      var response = UrlFetchApp.fetch(url, fetchOptions);
      Logger.log(response.getResponseCode());
      if(response.getResponseCode() != 200){
        throw new Error(response.getContentText())
      }else{
        return JSON.parse(response.getContentText());
      }
    }
  },
  Url:{
    insert: function (obj){
      var path = '/shorten';
      var callOptions = {method:"POST",payload:JSON.stringify({
          "long_url": obj.longUrl,
          "group_guid": UrlShortener.Util.getCachedProperty('BITLY_GUID')
        })};
      var r = UrlShortener.Util.CALL_(path,callOptions)
      return {id:r.link};
    }
  },
  Groups:{
    list: function(){
      var path = '/groups';
      var callOptions = {method:"GET"};
      return UrlShortener.Util.CALL_(path,callOptions);
    }
  }
});

setGUID: function(guid){
PropertiesService.getScriptProperties().setProperty('BITLY_GUID', token)
},

this metod needs fix "token" should be guid..

Could you also pls tell me where I can get that guid? I was able to generate token, but i cant get the guid.. thx