How to remove selected option from the option list in select2 multiselect and show selected options in the order they are selected

Question

I have select2 multi select field in my form where I want to remove the selected option from the dropdown list after it is selected and again add it to the list if it is removed

Answer 1

Another approach to hide the selected values, is to use the dropdown templateResult option to return null when the value is marked as selected.

function hideSelected(value) {
  if (value && !value.selected) {
    return $('<span>' + value.text + '</span>');
  }
}

$(document).ready(function() {
  $('#dynamicAttributes').select2({
    allowClear: true,
    placeholder: {
      id: "",
      placeholder: "Leave blank to ..."
    },
    minimumResultsForSearch: -1,
    width: 600,
    templateResult: hideSelected,
  });
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<link href="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.2/css/select2.min.css" rel="stylesheet" />
<script src="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.2/js/select2.min.js"></script>

<select id="dynamicAttributes" multiple="true" data-tags="true">
  <option value="1">A</option>
  <option value="2">B</option>
  <option value="3">C</option>
</select>

Answer 2

Remove (UnSelect) item from select2 multiple selected items

first step: add 'multiple' css class to your select2 element to get the true element which you want

<select class="multiple">
....
</select>

    $('select.multiple').on('select2:selecting', function (e) {
        var select = this;
        var idToRemove = '0';
        var selections = $(select).select2('data');

        var Values = new Array();

        for (var i = 0; i < selections.length; i++) {
            if (idToRemove !== selections[i].id) {
                Values.push(selections[i].id);
            }
        }
        $(select).val(Values).trigger('change');
    });

Answer 3

my solution was modified the select2.js (the core, version 4.0.3) in the line #3158. Add the following verification :

if ($option[0].selected == true) {
      return;
}

With this verification, we can exclude from the dropdown list, the selected ones. And if you write the name of a selected option, appear the text of option "noResult" .

Here the complete code:

SelectAdapter.prototype.query = function (params, callback) {
    var data = [];
    var self = this;

    var $options = this.$element.children();

    $options.each(function () {
      var $option = $(this);    
      if (!$option.is('option') && !$option.is('optgroup') ) {
        return;
      }

      if ($option[0].selected == true) {
           return;
      }

      var option = self.item($option);    
      var matches = self.matches(params, option);    
      if (matches !== null) {
        data.push(matches);
      }
    });

    callback({
      results: data
    });
  };

Answer 4

$(document).ready(function(){
  $('#dynamicAttributes').select2({
        allowClear: true,
        minimumResultsForSearch: -1,
        width: 600
  });
});

this make a error when click the remove sign button

TypeError: this.placeholder is undefined

use

 $(document).ready(function(){
      $('#dynamicAttributes').select2({
            allowClear: true,
            minimumResultsForSearch: -1,
            width: 600,
            placeholder: 'past your placeholder'

      });
});

Answer 5

I find a way to make the selected values not to appear anymore on the selection pop up list

On the documentation you can they have list of events Select2 events

open

I make use of these select2 event open to hide the selected values

Here is the javascript ::

$(document).ready(function() {

  $('#dynamicAttributes').select2({
      allowClear: true,
      minimumResultsForSearch: -1,
      width: 600
  });

  // override the select2 open event
  $('#dynamicAttributes').on('select2:open', function () {
    // get values of selected option
    var values = $(this).val();
    // get the pop up selection
    var pop_up_selection = $('.select2-results__options');

    if (values != null ) {
      // hide the selected values
       pop_up_selection.find("li[aria-selected=true]").hide();

    } else {
      // show all the selection values
      pop_up_selection.find("li[aria-selected=true]").show();
    }

  });

});

Here is a DEMO

Hope it helps.

Answer 6

Part #1 of Q:

You can do a CSS trick to hide selected item like this:

.select2-results__option[aria-selected=true] {
    display: none;
}

Part #2 of Q:

Also you can do a JQuery trick to force selected items to end of tags box, ( by getting selected item on select, detach it (remove it), then reAppend it to tags box, then call "change function" to apply changes ):

$("select").on("select2:select", function (evt) {
    var element = evt.params.data.element;
    var $element = $(element);
    $element.detach();
    $(this).append($element);
    $(this).trigger("change");
});

Finally Updated JsFiddle, I hope it works for you, Thanks !

Edit #1

You can Clear All Selected by this call (apply Null values):

$("#dynamicAttributes").val(null).trigger("change"); 

on Button:

$('#btnReset').click(function() {
    $("#dynamicAttributes").val(null).trigger("change"); 
});

Updated Fiddle #2