telegram.js

var request = require('request');

var telegramApiEndpoint = "https://api.telegram.org/bot"

module.exports = () => {
  this.telegramApi = "";

  this.sendRequest = (method, data, callback) => {
    request.post({url: this.telegramApi + "/" + method, body: data, json:true}, callback);
  }

  var response = {};
  response.createConnection = (token, urlWebhook, callback) => {
    //check if token is set:
    if(!token) { throw "You must provide a telegram bot token"};
    if(!urlWebhook) { throw "You must provide a webhook url"};

    this.telegramApi = telegramApiEndpoint + token;
    var data = {url: 'https://' + urlWebhook};
    this.sendRequest('setWebhook', data, (err, response, body) => {
      callback(err);
      console.log('telegram connection to ' + urlWebhook + ' : ', body);
    });
  };

  response.sendMessage = (to, text, keyboard, callback) => {
    var data = {
      chat_id: to,
      text: text,
      reply_markup: keyboard
    };
    this.sendRequest('sendMessage', data, (err, response, body) => {
      callback(err);
    });
  };

  return response;
}