Get an event data from a Spark core using NodeJS

Get event data

/*jslint node: true */
"use strict";
var spark = require('spark');
var fs = require('fs'); 
	spark.on('login', function() {
//Get test event for specific core
	spark.getEventStream('MyEvent', '00000000000000000', function(data) {
	console.log("New Event: " + JSON.stringify(data) + ". Logging it to file");
	fs.appendFile('Carpet1 Sensors Data.txt', data.data + "," +
	data.published_at + "," + data.name + "\r\n", function (err) {
      		if(err)
          console.log("File log failure. Error = " + JSON.stringify(err));
      		else
          console.log("File log success");
		});
	});
});

// Login as usual
	spark.login({ username: 'Myemail@gmail.com', password: 'MyPassword'});

I can't test this, but just a shot in the dark...

/*jslint node: true */
"use strict";
var spark = require('spark');
var fs = require('fs');
spark.on('login', function() {
//Get test event for specific core
spark.getEventStream('MyEvent', '00000000000000000', function(data) {
console.log("New Event: " + JSON.stringify(data) + ". Logging it to file");

    var published = new Date(data.published_at); // Create a new Date object with the published_at string

fs.appendFile('Carpet1 Sensors Data.txt', data.data + "," +
    published.toLocalString() + "," + data.name + "\r\n", function (err) {
        if(err)
      console.log("File log failure. Error = " + JSON.stringify(err));
        else
      console.log("File log success");
    });
});

});

// Login as usual
spark.login({ username: 'Myemail@gmail.com', password: 'MyPassword'});

I tried to find documentation on published_at but I couldn't find any. It seems like if you are getting a GMT or UTC string, you could just convert it to a date object and the do the conversion to local time. If it is already a Date object it should be even more simple, but I assume that the solution isn't as simple as it seems to me. What have you already tried? You said that you tried the toLocalString() method... what were the results? Did you get an error?
I'm sorry if this doesn't help.