JSFiddle - React, Tailwind, and code Playground

HTML

<a>click</a>

<div class="drop user-menu">user menu asd</div>

CSS

.drop {
    display:none;
    background:blue;
}
a {
    background:black;
    color:white;
}

JavaScript

$('a').on('click', function (e) {
    e.stopPropagation();
    $('.drop.user-menu').fadeIn();
});
$('.drop.user-menu').on('click', function (e) {
    e.stopPropagation();
    $('.drop.user-menu').fadeIn();
});
$(document).on('click', function (e) {
    if (e.target != $('.drop.user-menu')) {
        $('.drop.user-menu').fadeOut();
    }
});