JSFiddle - React, Tailwind, and code Playground

HTML

<div id="main">
<ul>
<li>Item 1</li>
<li>Item 2</li>
<li>Item 3</li>
<li>Item 4</li>
</ul>
</div>

JavaScript

$('#main ul li:eq(3)').clone().insertBefore('#main ul li:eq(2)');