JSFiddle - React, Tailwind, and code Playground

HTML

<div class="1 btn">Foo 1</div>
<div class="2 btn">Foo 2</div>
<div class="3 btn">Foo 3</div>
<div class="4 btn">Foo 4</div>
<div class="5 btn">Foo 5</div>
<div class="6 btn">Foo 6</div>
<div class="7 btn">Foo 7</div>
<div class="8 btn">Foo 8</div>
<div class="9 btn">Foo 9</div>

CSS

.red {
    color: red;
}

JavaScript

var array = [1, 6, 2, 9, 5];

$(".btn").filter(function() {
    return array.some($.fn.hasClass.bind($(this)));
}).addClass("red");