pulling data on Zabbix api with node express app

I am trying to use Zabbix API to pull somedata. I use in a node app using express and zabbix node (https://libraries.io/npm/zabbix-node). My main problem is that all the var in console.log are undefined. I don't understand why ? ( I'm sure my login username, pass ans server address are right)

My code is :

var express = require("express");
var fs = require('fs');
var app = express();
var Zabbix = require ("zabbix-node");

app.get('/', function (req, res) {
  var zabbix = new Zabbix('XXXX','XXX', 'XXX');

  zabbix.getApiVersion(function (err, resp, body) {
      if (!err) {
        console.log("Unauthenticated API version request, and the version is: " + body.result)
      }
  });

  zabbix.login(function (err, resp, body) {
    if (!err) {
      console.log("Authenticated! AuthID is: " + zabbix.authid);
    }


    zabbix.getApiVersion(function (err, resp, body) {
        console.log("Zabbix API version is: " + body.result);     
    });

  });

});

via DR.DRE