JSFiddle - React, Tailwind, and code Playground

HTML

<a href="#" class="trigger">menu</a>
<div class="menu">Hello</div>

CSS

.menu
{
    display: none;
    background: yellow;
}

JavaScript

$(".trigger").on("click", function(event)
{
    $(".menu").toggle();
    event.stopPropagation();
});

$(".menu").on("click", function(event)
{
    event.stopPropagation();
});

$(document).on("click", function(event)
{
    $(".menu").hide();
});