JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://getfirebug.com/releases/lite/1.2/firebug-lite-compressed.js"></script>

JavaScript

$.fn.extend({

    hasData: function(key) {
        return !(typeof $(this).data(key) == "undefined");
    }
});

var a = $("<div/>");
console.log(a.hasData("darthvader"));

a.data("darthvader", "sith");
console.log(a.hasData("darthvader"));

a.removeData("darthvader");
console.log(a.hasData("darthvader"));