node-telegram-bot-api/examples/replyToMessage.js

'use strict';

var TelegramBot = require('node-telegram-bot-api');

var TOKEN = 'BOT_TOKEN';
var USER = 'USER_ID';

var bot = new TelegramBot(TOKEN, {polling: {timeout: 1, interval: 100}});

bot.sendMessage(USER, 'How old are you?')
  .then(function (sended) {
    var chatId = sended.chat.id;
    var messageId = sended.message_id;
    bot.onReplyToMessage(chatId, messageId, function (message) {
      console.log('User is %s years old', message.text);
    });
  });