JSFiddle - React, Tailwind, and code Playground
HTML
<ul>
<li>
<article>
<div class="player"></div>
</article>
</li>
<li>
<article>
<div class="player currentPlayer"></div>
</article>
</li>
<li>
<article>
<div class="player"></div>
</article>
</li>
</ul>
JavaScript
var aa = ["a", "b"];
$(function() {
alert(aa.inArray("a"));
});