Validação de data do datepicker

Validação de data do datepicker

HTML

<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/jqueryui/1.11.2/jquery-ui.min.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/jqueryui/1.11.2/jquery-ui.min.js"></script>
<div class="container">
    <input id="from" type="data">
    <input id="actualDate" type="data">
</div>

JavaScript

$( "#from" ).datepicker({
    dateFormat: "dd/mm/yy",
    altFormat: "yy-MM-dd",
    altField: "#actualDate",
    maxDate: "+10d",
    beforeShow: function(){
        $(this).on('focusout', function(){
            var data = $(this).val();
            console.log(data);
             
            // FAÇA A VALIDAÇÃO DA DATA DIGITADA AQUI
            
            var RegExPattern = /^((((0?[1-9]|[12]\d|3[01])[\.\-\/](0?[13578]|1[02])      [\.\-\/]((1[6-9]|[2-9]\d)?\d{2}))|((0?[1-9]|[12]\d|30)[\.\-\/](0?[13456789]|1[012])[\.\-\/]((1[6-9]|[2-9]\d)?\d{2}))|((0?[1-9]|1\d|2[0-8])[\.\-\/]0?2[\.\-\/]((1[6-9]|[2-9]\d)?\d{2}))|(29[\.\-\/]0?2[\.\-\/]((1[6-9]|[2-9]\d)?(0[48]|[2468][048]|[13579][26])|((16|[2468][048]|[3579][26])00)|00)))|(((0[1-9]|[12]\d|3[01])(0[13578]|1[02])((1[6-9]|[2-9]\d)?\d{2}))|((0[1-9]|[12]\d|30)(0[13456789]|1[012])((1[6-9]|[2-9]\d)?\d{2}))|((0[1-9]|1\d|2[0-8])02((1[6-9]|[2-9]\d)?\d{2}))|(2902((1[6-9]|[2-9]\d)?(0[48]|[2468][048]|[13579][26])|((16|[2468][048]|[3579][26])00)|00))))$/;

     if (!((data.value.match(RegExPattern)) && (data.value!=''))) {
          alert('Data inválida.');
   id.focus();
        }
       else
        alert('Data válidaa.');
            
        });
    }
});