JSFiddle - React, Tailwind, and code Playground

HTML

<p>Click the blue (child) div to match the background of the parent</p> 
<div class="parent">
        <div class="child">
    </div></div>

CSS

.parent {
    width: 100px;
    height: 100px;
    background: red;
}
.child {
    width: 50px;
    height: 50px;
    background: blue;
}

JavaScript

$('.child').on('click',  function(event) {
    var bg = $(this).parent().css("background-color"); // finds background color of parent
    $(this).css("display",'none');  //  applies background color to child
});