JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://raw.githubusercontent.com/kapetan/jquery-observe/master/jquery-observe.js"></script>
<div id="me" class="red">Click Me....!</div>

CSS

.red {
    color:red;
}
.blue {
    color:blue;
}

JavaScript

$(function () {
    $('#me').click(function () {
        $(this).toggleClass("red blue");
    });

    $('#me').observe({
        attributes: true,
        attributeFilter: ['class']
    }, function (record) {
        console.log(record);
        fireMe();
    });

    //It would fir twice as toggleClass removes a class and adds a new class
    var fireMe = function () {
        alert('Class changed');
    }
});