JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
   <li class="expandable">Game
     <ul>
        <li>- Action</li>
        <li>- RPG</li>
     </ul>
   </li>
   <li class="expandable">BBS
     <ul>
       <li class="expandable">- Group 1
          <ul>
             <li>-- Board 1</li>
             <li>-- Board 2</li>
          </ul>
       </li>
       <li class="expandable">- Group 2
          <ul>
             <li>-- Board 1</li>
          </ul>
       </li>
     </ul>
   </li>
</ul>

JavaScript

$('li.expandable').click(function() {
    $(this).children('ul').toggle();
    return false;
});