JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
    <a class="abc">ABC</a>
    <div id="def">TEST</div>
</div>

JavaScript

$('.abc').mouseenter(function(e) {
    $('#def').show(200);
});
$('#container').mouseleave(function(e){
    $('#def').hide(200);
});