JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://ajax.aspnetcdn.com/ajax/jquery.ui/1.8.17/themes/black-tie/jquery-ui.css">
<script src="http://ajax.aspnetcdn.com/ajax/jquery.ui/1.8.17/jquery-ui.min.js"></script>
<input id="resDate">

JavaScript

$(document).ready(function () {
   blackoutDates(); 
});
function blackoutDates() {
    var unavailableDates = ["09/27/2018", "11/8/2018", "4/25/2018"]
$(function () {
            $("#resDate").datepicker({
                todayHighlight: true,
                beforeShowDay: function (date) {
                    var string = jQuery.datepicker.formatDate('mm-dd-yy', date);
                    return [unavailableDates.indexOf(string) == -1]
                }
            });
        });
   }