Amazon Echo I.S.S. Tracker Skill

issTracker.js

'use strict';
var http = require('http');

const Alexa = require('alexa-sdk');
var alexa;

const handlers = {
    'LaunchRequest': function () {
        this.emit('GetLocation');
    },
    'GetLocationIntent': function () {
        this.emit('GetLocation');
    },
    'GetLocation': function () {
        var speechOutput = '';
        var cardOutput = '';
        httpGet('api.open-notify.org', '/iss-now.json', function (response) {
            var responseData = JSON.parse(response);
            if (responseData === null) {
                speechOutput = 'I have no idea where it is.';
                cardOutput = 'There was an error.'
            } else {
                speechOutput = 'I have found it. It is at latitude ' + responseData.iss_position.latitude + ', and longitude ' + responseData.iss_position.longitude;
                cardOutput = responseData.iss_position.latitude + ', ' + responseData.iss_position.longitude;   
            }
            alexa.emit(':tellWithCard', speechOutput, 'I.S.S. Current Co-ordinates - ' + new Date(responseData.timestamp * 1e3).toISOString(), cardOutput);
        });
    },
    'AMAZON.HelpIntent': function () {
        const speechOutput = this.t('HELP_MESSAGE');
        const reprompt = this.t('HELP_MESSAGE');
        this.emit(':ask', speechOutput, reprompt);
    },
    'AMAZON.CancelIntent': function () {
        this.emit(':tell', this.t('STOP_MESSAGE'));
    },
    'AMAZON.StopIntent': function () {
        this.emit(':tell', this.t('STOP_MESSAGE'));
    },
    'SessionEndedRequest': function () {
        this.emit(':tell', this.t('STOP_MESSAGE'));
    },
};

exports.handler = (event, context) => {
    alexa = Alexa.handler(event, context);
    alexa.registerHandlers(handlers);
    alexa.execute();
};

function httpGet(location, file, callback) {
    var options = {
        host: location,
        path: file,
        method: 'GET'
    };
    var req = http.request(options, (res) => {
        var body = '';
        res.on('data', (d) => {
            body += d;
        });
        res.on('end', function () {
            callback(body);
        });
    });
    req.end();
}