JSFiddle - React, Tailwind, and code Playground

HTML

<div class="parent">
    <div class="child"></div>
</div>

<div class="parent">
</div>

CSS

.parent
{
    margin:10px;
    background:red;
    width:100px;
    height:100px;
}

.parent.myClass
{
    border:4px solid #750000;
}

JavaScript

$(function(){
    
    $('.parent:has(.child)').addClass('myClass');
    
});