How could to manage two same select2, hide and show selected item from another select2-CodePudding

According this question I able to add selected item to another select.

Consider we have two select2, with same options. When I select item from box1, same item should removed from box2 and user couldn't select it. I provide it on jsfiddle.net.

Now I want to unselected it, the box2 should have that item again.

<select  multiple id="Box1" name="Box1" style='width:325px;float:left;border:1px solid #80C7E2;'>
    <option value="1">A</option>                                
    <option value="2">B</option>                                
    <option value="3">C</option>                                
    <option value="D">D</option>                                
</select>

<select  multiple id="Box2" name="Box2" style='width:325px;float:left;border:1px solid #80C7E2;'>
    <option value="1">A</option>                                
    <option value="2">B</option>                                
    <option value="3">C</option>                                
    <option value="D">D</option>                                
</select>

‌

$("#Box1").select2();
$("#Box2").select2();


$("#Box1").on("change", function() {
    $.each($('#Box1').select2('data'), function(i, item) {
       $('#Box2 option[value="' item.id '"]').remove();
         });
});

CodePudding user response：

Try this, it's may help :

$("#Box1").select2();
$("#Box2").select2();

$("#Box1").on("change", function(e) 
{       
    $("#Box2").html("");
    $('#Box1 option').each(function()
    {
        if($("#Box1").val())
      {
          if($("#Box1").val().some(e=>{return e == $(this).val()}))
          {
              $('#Box2 option[value="' $(this).val() '"]').remove();
          }
          else if(!$("#Box2 option").toArray().some(e=>{return e.value == $(this).val()}))
          {          
             $("#Box2").append($('<option>', {value: $(this).val(), text: $(this).text()}));
          } 
      }
      else
      {
        $("#Box2").html($("#Box1").html());
      }    
    }); 
});

<link href="https://cdnjs.cloudflare.com/ajax/libs/select2/3.5.2/select2.min.css" rel="stylesheet"/>
<select  multiple id="Box1" name="Box1" style='width:325px;float:left;border:1px solid #80C7E2;'>
    <option value="1">A</option>                                
    <option value="2">B</option>                                
    <option value="3">C</option>                                
    <option value="D">D</option>                                
</select>

<select  multiple id="Box2" name="Box2" style='width:325px;float:left;border:1px solid #80C7E2;'>
    <option value="1">A</option>                                
    <option value="2">B</option>                                
    <option value="3">C</option>                                
    <option value="D">D</option>                                
</select>

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/select2/3.5.2/select2.min.js"></script>