JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wrapp">
  <div class="firstChild">
    <ul class="firstChild__list">
      <li class="firstChild__item">
        <a href="#" id="firstChild__link">text</a>
      </li>
      <li class="firstChild__item">text</li>
      <li class="firstChild__item">text</li>
    </ul>
  </div>
  <div class="secondChild">
    <ul class="secondChild__list">
      <li class="secondChild__item">another text</li>
      <li class="secondChild__item">another text</li>
      <li class="secondChild__item">another text</li>
      <li class="secondChild__item">another text</li>
      <li class="secondChild__item">another text</li>
    </ul>
  </div>
</div>

JavaScript

let childElement = document.querySelector('#firstChild__link');
let parentElement = document.querySelector('.firstChild'); 

function checkParent(parent, child){
	return child.closest(parent);
}

console.log(checkParent(parentElement, childElement));