How can I include an if condition into switch to deel with this code

I have these variables :

« PST_INFINCDEM » is select group = (indicent=0/ demande=1) « PST_INFBLOQ » is a checkbox = (O / N) « DT_READEM » with type date.

I want to calculate the « DT_READEM » deppending on three conditions: 1- if PST_INFINCDEM = demande then DT_READEM =CURRENT Date +10 days 2- if PST_INFINCDEM = incident AND PST_INFBLOQ =O THEN DT_READEM =CURRENT Date + 2 Days 3- if PST_INFINCDEM = incident AND PST_INFBLOQ =N THEN DT_READEM =current Date + 5 days

$(document).ready(function() {

$('select').change(function(){
   var item=$('select').val();
   var checkedItem = $("#PST_INFBLOQ").is(":checked");

    switch (item){
    case "1":
    var newdate = new Date();

                                  newdate.setDate(newdate.getDate() + 10);
    
                                  var dd = newdate.getDate();
                                  var mm = newdate.getMonth() + 1;
                                  var y = newdate.getFullYear();
                                  if(mm<10) mm='0'+mm;
                                  var someFormattedDate = dd + '/' + mm + '/' + y;
                                  //document.getElementById('DT_READEM').value = someFormattedDate;
                                $('#DT_READEM').val(someFormattedDate);
            break;
    case "0":
    
    
$('#checkedItem ').click(function (event) {
    if (checkedItem === false)
    {                            
    var newdate_5 = new Date();

    newdate_5.setDate(newdate.getDate() + 5);
    
                                  var dd = newdate_5.getDate();
                                  var mm = newdate_5.getMonth() + 1;
                                  var y = newdate_5.getFullYear();
                                  if(mm<10) mm='0'+mm;
                                  var someFormattedDate = dd + '/' + mm + '/' + y;
                                  //document.getElementById('DT_READEM').value = someFormattedDate;
                                $('#DT_READEM').val(someFormattedDate);
                                
    }                                 
else    if (checkedItem === true)
{
    var newdate_2 = new Date();
                               
                               newdate_2.setDate(newdate_2.getDate() + 2);
    
                                  var dd = newdate_2.getDate();
                                  var mm = newdate_2.getMonth() + 1;
                                  var y = newdate_2.getFullYear();
                                  if(mm<10) mm='0'+mm;
                                  var someFormattedDate = dd + '/' + mm + '/' + y;
                                  //document.getElementById('DT_READEM').value = someFormattedDate;
                                $('#DT_READEM').val(someFormattedDate);
}
})
    
break;
default: 
$('#DT_READEM').val(new Date().toLocaleDateString()).attr('disabled','disabled');
    }
})
})  

Resources

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.0/jquery.min.js"></script>
<div>
  <span> date </span>
  <input type="date" id="DT_READEM">
</div>
<div>
  <span> bloc </span>
  <input type="checkbox" id="PST_INFBLOQ ">
</div>
<div>
  <span> info </span>
 <select id="pet-select" id="PST_INFINCDEM ">
    
    <option value=1>demande</option>
    <option value=0>indicent</option>
   
</select>
</div>

The problem that the result that want is true just when i select "demande" if i select "indicent" nothing is change and the checkbox is not taken into considaration even I put a condition about it