JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
<li>Item</li>
<li>Item</li>
<li>Item</li>
<li class='toHide'>Item</li>
<li class='toHide'>Item</li>
<li class='toHide'>Item</li>
</ul>

CSS

.toHide
{
  background-color: lavender; 
}

JavaScript

var lastItemIndex = 3;
$('li:eq('+(lastItemIndex)+')').css("opacity", 0);