JSFiddle - React, Tailwind, and code Playground

HTML

<ul class="toggle-list">
  <li>
    <a href="#">Item 1</a>
  </li>
  <li>
    <a href="#">Item 2</a>
    <ul>
      <li>
         <a href="#">Item 2-1</a>
      </li>
      <li>
         <a href="#">Item 2-2</a>
      </li>
      <li>
         <a href="#">Item 2-3</a>
         <ul>
            <li>
               <a href="#">Item 2-3-1</a>
            </li>
            <li>
               <a href="#">Item 2-3-2</a>
            </li>
         </ul>
      </li>
    </ul>
  </li>
  <li>
    <a href="#">Item 3</a>
  </li>
</ul>

CSS

body {
  font-family: Monaco;
  font-weight: 200;
  padding-top:10px;
}

ul ul {
  display: none;
}

JavaScript

$(document).ready(function() {
$('.toggle-list a').click(function(e){

  e.preventDefault(); // https://api.jquery.com/event.preventdefault/
  $(this).siblings('ul').slideToggle('slow'); // Toggle de l'élément ul frère

});	
});