JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://ajax.microsoft.com/ajax/jquery.ui/1.8.9/themes/start/jquery-ui.css">
<input type='text' id='txtDate' />

JavaScript

var unavailableDates = ["21-12-2011"];

function unavailable(date) {
  dmy = date.getDate() + "-" + (date.getMonth()+1) + "-" + date.getFullYear();
  if ($.inArray(dmy, unavailableDates) == -1) {
    return [true, ""];
  } else {
    return [false,"","Unavailable"];
  }
}

function disabledays(date) {
        var day = date.getDay();
        return [(day != 0 && day != 2)];
        
    
    } 

$('#txtDate').datepicker({ 
    beforeShowDay: disabledays

})