old_contents: 'use strict';
  
  const TeleBot = require('../');
  const bot = new TeleBot('-PASTEYOURTELEGRAMBOTAPITOKENHERE-');
  
  var lastMessage;
  var photoUrl = 'https://telegram.org/img/tl_card_destruct.gif'
  
  bot.on('/start', msg => {
  
    // Send image with caption
    return bot.sendPhoto(
      msg.from.id, photoUrl, { caption: 'This is a default caption.' }
    ).then(re => {
      // Get message id and chat
      lastMessage = [msg.from.id, re.result.message_id];
      bot.sendMessage(msg.from.id, 'Now set a new caption using /edit <catpion>');
    });
  
  });
  
  bot.on('/edit', msg => {
  
    if (!lastMessage)
      return bot.sendMessage(msg.from.id, 'Type /start and then /edit <caption>');
  
    let [chatId, messageId] = lastMessage;
    let caption = msg.text.replace('/edit ', '');
  
    if (caption == '/edit') caption = 'No caption.';
  
    // Change caption
    return bot.editCaption({ chatId, messageId }, caption).then(x => {
      bot.sendMessage(msg.from.id, `Caption changed to: ${ caption }`);
    });
  
  });
  
  bot.connect();
  
new_contents: 'use strict';
  
  const TeleBot = require('../');
  const bot = new TeleBot('-PASTEYOURTELEGRAMBOTAPITOKENHERE-');
  
  var lastMessage;
  var photoUrl = 'https://telegram.org/img/tl_card_destruct.gif'
  
  bot.on('/start', msg => {
  
    // Send image with caption
    return bot.sendPhoto(
      msg.from.id, photoUrl, { caption: 'This is a default caption.' }
    ).then(re => {
      // Get message id and chat
      lastMessage = [msg.from.id, re.result.message_id];
      bot.sendMessage(msg.from.id, 'Now set a new caption using /edit <caption>');
    });
  
  });
  
  bot.on('/edit', msg => {
  
    if (!lastMessage)
      return bot.sendMessage(msg.from.id, 'Type /start and then /edit <caption>');
  
    let [chatId, messageId] = lastMessage;
    let caption = msg.text.replace('/edit ', '');
  
    if (caption == '/edit') caption = 'No caption.';
  
    // Change caption
    return bot.editCaption({ chatId, messageId }, caption).then(x => {
      bot.sendMessage(msg.from.id, `Caption changed to: ${ caption }`);
    });
  
  });
  
  bot.connect();
  
subject: fix typo