index.js

'use strict';

const express = require('express'),
      config = require('config'),
      Intelligo = require('intelligo');

const app = express();

const bot = new Intelligo({
  PAGE_ACCESS_TOKEN: config.get('PAGE_ACCESS_TOKEN'),
  VALIDATION_TOKEN: config.get('VALIDATION_TOKEN'),
  APP_SECRET: config.get('APP_SECRET'),
  app: app
});

bot.initWebhook();

//Subscribe to messages sent by the user with the bot.on() method.
bot.on('message', (event) => {

  const senderID = event.sender.id,
        message = event.message;

  if (message.text) {
      bot.sendTextMessage(senderID, "Hello world");
  }
});
app.set('port', process.env.PORT || 5000);
app.listen(app.get('port'), function() {
  console.log('Server is running on port', app.get('port'));
});