Setting attributes only (without returning any bot response)

index.js

'use strict';

const express = require('express');
const bodyParser = require('body-parser');
const app = express().use(bodyParser.json()); // creates http server
const token = 'TOKEN'; // type here your verification token

app.get('/', (req, res) => {
    // check if verification token is correct
    if (req.query.token !== token) {
        return res.sendStatus(401);
    }

    // return challenge
    return res.end(req.query.challenge);
});


app.post('/', (req, res) => {
    // check if verification token is correct
    if (req.query.token !== token) {
        return res.sendStatus(401);
    }
  
    // print request body
	console.log(req.body);

    // return responses and actions
    const data = {
	// return attributes
	attributes: {
		signedUpForNewsletter: 'yes'
	}
    };

    res.json(data);
});

app.listen(3000, () => console.log('[ChatBot] Webhook is listening'));