JSFiddle - React, Tailwind, and code Playground

HTML

<ul class="dropdownlist">
    <li class="selected">Item 1</li>
    <li>Item 2</li>
    <li>Item 3</li>
    <li>Item 4</li>
    <li>Item 5</li>
</ul>

CSS

ul.dropdownlist {
	list-style:none;
    border:1px solid red;
    width:200px;
}

.dropdownlist li {
	display:none;
}


.selected  {
	display:block !important;
}

JavaScript

$('.dropdownlist li').click(function(){
    $(this).toggleClass("selected");
    $(this).parent().children().toggle();
    event.stopPropagation();
});
$(document).on('click', function () {
    $(".dropdownlist li").parent().children(":not(.selected)").hide();
});