SlackBot message posting with TypeScript

slackbot.ts

import https = require('https');
import * as Constants from './constants';
import * as qs from 'qs';

export class SlackBot {
  options = {
    token: '',
    channel: '',
    username: '',
    icon_url: ''
  }
  
  constructor() {
    let pkg = require('./package.json');
    if (pkg.slackbot) {
      this.options = pkg.slackbot;
    }
  }
  
  postTextWithCode(text: string, code: string) : Promise.IThenable<JSON> {
    let message = text + '\n```' + code + '```\n';
    return this.postMessage(message);
  }
  
  postMessage(text: string) : Promise.IThenable<JSON> {
    let p = new Promise((resolve, reject) => {
      let queryString = qs.stringify({
        token: this.options.token,
        channel: this.options.channel,
        username: this.options.username,
        icon_url: this.options.icon_url,
        text: text
      });
      
      let options = {
        host: 'slack.com',
        port: 443,
        path: '/api/chat.postMessage?' + queryString,
        method: 'POST'
      };
      
      let data = [];
      
      let req = https.request(options, function(res) {
          res.on('data', function(chunk) {
              data.push(chunk);
          });
          
          res.on('end', () => {
            try {
              let text = Buffer.concat(data).toString();
              var json = JSON.parse(text);
              resolve(json);
            }
            catch (e) {
              var error = new Error('Failed to handle response');
              let thrownError: Error = e;
              error.stack = thrownError.stack;
              reject(error);
            }
          });
      });

      req.on('error', (e) => {
        console.error(e);
        reject(e);
      })

      req.end();
    });
    
    return p;
  }
}