Observe Youtube Chat Room Items

observe.js

var $chatList = document
  .querySelector('#chatframe')
  .contentWindow
  .document
  .querySelector('#item-offset #items')
 
var observer = new MutationObserver(([{ target }]) => {
  const items = [...target.querySelectorAll('yt-live-chat-text-message-renderer')]
    .map($el => ({
      img: $el.querySelector('#img').getAttribute('src'),
      timestamp: $el.querySelector('#timestamp').innerText,
      authorName: $el.querySelector('#author-name').innerText,
    }))
  
  console.log(items[items.length - 1]) // 印出列表的最後一項
})

observer.observe($chatList, { childList: true })