JSFiddle - React, Tailwind, and code Playground

HTML

<div class="widget">white</div>
<div class="widget">black</div>
<div class="widget">red</div>
<div class="widget">green</div>

CSS

.fg-white{
    background:white;
}
.fg-black{
    background:black;
}
.fg-red{
    background:red;
}
.fg-green{
    background:green;
}

JavaScript

var colors = ["white", "black", "red", "green"];

$('.widget').each(function(i) {
  $(this).addClass("fg-"+colors[i % colors.length]);
});