JSFiddle - React, Tailwind, and code Playground

HTML

<div class="bam">
    <div class="wow">
    </div>
</div>

CSS

.bam {height:400px; width:400px; background-color:red;}

.wow {height:200px; width:200px; background-color:blue;}

JavaScript

$(".bam").css("height", $('.wow').css("height"));