JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://code.jquery.com/jquery-latest.min.js"></script>

<div id='cssmenu'>
        <ul>
            <li><a href='http://internallink.com/home'><span>Home</span></a></li>
            <li class='active has-sub'><a href='http://internallink.com/products'><span>Products</span></a>
                <ul>
                    <li class='has-sub'><a href='http://internallink.com/product1'><span>Product 1</span></a>
                        <ul>
                            <li><a href='http://internallink.com/subProduct'><span>Sub Product</span></a></li>
                            <li class='last'><a href='http://internallink.com/subProduct'><span>Sub Product</span></a></li>
                        </ul>
                    </li>
                    <li class='has-sub'><a href='http://internallink.com/product2'><span>Product 2</span></a>
                        <ul>
                            <li><a href='http://internallink.com/subProduct'><span>Sub Product</span></a></li>
                            <li class='last'><a href='http://internallink.com/subProduct'><span>Sub Product</span></a></li>
                        </ul>
                    </li>
                </ul>
            </li>
            <li><a href='http://internallink.com/about'><span>About</span></a></li>
            <li class='last'><a href='http://internallink.com/contact'><span>Contact</span></a></li>
        </ul>
    </div>

CSS

#cssmenu, #cssmenu ul, #cssmenu ul li, #cssmenu ul li a { margin: 0; padding: 0; border: 0; list-style: none; line-height: 1; display: block; position: relative; -webkit-box-sizing: border-box; -moz-box-sizing: border-box; box-sizing: border-box; }
#cssmenu { width: 180px; font-family: "Segoe UI","Segoe UI","Segoe",Tahoma,Helvetica,Arial,sans-serif; color: #ffffff; }
#cssmenu ul ul { display: none; }
.align-right { float: right; }
#cssmenu > ul > li > a { padding: 10px 15px 10px 30px; cursor: pointer; z-index: 2; font-size: 13px; font-weight: normal; text-decoration: none; color: #ffffff; background: #ae53a2; }
#cssmenu > ul > li > a:hover, #cssmenu > ul > li.active > a, #cssmenu > ul > li.open > a { color: #fff; background: #ae53a2; }
#cssmenu > ul > li:last-child > a, #cssmenu > ul > li.last > a { border-bottom: 1px solid #1682ba; }
.holder { width: 20px; height: 20px; cursor:pointer; position: absolute; top: 6px; left: 5px; display: block; z-index: 99; }
#cssmenu ul ul .holder { left: 15px; }
.holder:after, .holder:before { display: block; position: absolute; content: ""; width: 6px; height: 6px; left: 6px; z-index: 10; -webkit-transform: rotate(-135deg); -moz-transform: rotate(-135deg); -ms-transform: rotate(-135deg); -o-transform: rotate(-135deg); transform: rotate(-135deg); }
.holder:after { top: 6px; border-top: 1px solid #ffffff; border-left: 1px solid #ffffff; }
.holder:before { top: 5px; border-top: 2px solid; border-left: 2px solid; border-top-color: inherit; border-left-color: inherit; }

#cssmenu ul ul .holder:after { border-top: 1px solid #666; border-left: 1px solid #666; }
#cssmenu ul ul .holder:before { border-top: 1px solid #666; border-left: 1px solid #666; }

#cssmenu ul ul li a { cursor: pointer; padding: 10px 20px; z-index: 1; text-decoration: none; font-size: 13px; color: #454444; background: #e6e6e6; }
#cssmenu ul ul li:hover > a, #cssmenu ul ul li.open > a, #cssmenu ul ul li.active > a { background: #ddd; }
#cssmenu ul ul li a {...

JavaScript

jQuery(document).ready(function () {
    jQuery('#cssmenu').on("click","li.has-sub .holder",function () {
		var element = jQuery(this).parent('li');
		if (element.hasClass('open')) {
			element.removeClass('open');
			element.find('li').removeClass('open');
			element.find('ul').slideUp();
		}
		else {
			element.addClass('open');
			element.children('ul').slideDown();
			element.siblings('li').children('ul').slideUp();
			element.siblings('li').removeClass('open');
			element.siblings('li').find('li').removeClass('open');
			element.siblings('li').find('ul').slideUp();
		}
	});

	jQuery('#cssmenu ul li.has-sub').prepend('<span class="holder"></span>');

});