JSFiddle - React, Tailwind, and code Playground

HTML

<ul id="nav">
    <li>Home</li>
    <li class="parent">About
        <ul class="sub-nav">
            <li>Johnny</li>
            <li>Julie</li>
            <li>Jamie</li>
        </ul>
    </li>
    <li>Contact</li>
</ul>

CSS

#nav ul.sub-nav {
    display: none;
}

#nav ul.visible {
    display: block;
}

JavaScript

$(document).ready(function() {
		$('.parent').click(function() {
			$('.sub-nav').toggleClass('visible');
		});
	});