javascript - Override function expression event listener not working

Question

I'm trying to override the function attached to the event listener but when the event is triggered the old one is still called.

var element;
var newHandler = () => {
  if((element = this.getElementsByClassName('someClass')[0]) != null){
    this.removeEventListener('DOMNodeInserted', handler )
    element.insertAdjacentHTML('beforeend', "<a>Hello</a>");
  }
}

var handler = () => {
  handler = newHandler;
  var scriptTag = document.createElement('script');
  scriptTag.src = "someScript.js";
  document.head.appendChild(scriptTag);
}

document.addEventListener('DOMNodeInserted', handler);

Any kind of help is really appreciated. Thanks a ton!

Answer 1

Found the solution

var element;
var newHandler = () => {
  if((element = this.getElementsByClassName('someClass')[0]) != null){
    document.removeEventListener('DOMNodeInserted', intermediary )
    element.insertAdjacentHTML('beforeend', "<a>Hello</a>");
  }
}

var handler = () => {
  handler = newHandler;
  var scriptTag = document.createElement('script');
  scriptTag.src = "someScript.js";
  document.head.appendChild(scriptTag);
}

var intermediary = () => handler();

document.addEventListener('DOMNodeInserted', intermediary );

I think the problem was caused by a kind of first level cache.