JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://code.jquery.com/ui/1.8.18/jquery-ui.min.js"></script>
<input id="pickerdiv" />

JavaScript

$('#pickerdiv').datepicker({
    beforeShowDay: function(date){
        if(date.getDate() == new Date().getDate() && date.getMonth() == new Date().getMonth()){
            alert(date.isValid());
        }
        //some code
        return [true, ''];
    }
});