JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
    <li>A</li>
    <li>B</li>
</ul>
<ul>
    <li>C</li>
    <li>D</li>
</ul>
<a href="#" class="switch_order">Switch</a>

JavaScript

$('body').on('click', '.switch_order', function(e){
  var list = $('ul');
  var listItems = list.children('li');
  list.append(listItems.get().reverse());
});