Select2 select all/none

by beaver71

HTML

<script src="https://code.jquery.com/jquery-3.2.1.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.5/js/select2.full.min.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.5/css/select2.min.css">
<select class="parent_filter_select2 pull-right" id="parent_filter_select2" multiple="multiple" name="select_project" style="width: 300px;">
        <option value="Option A">Option A</option>
        <option value="Option B">Option B</option>
        <option value="Option C">Option C</option>
        <option value="Option D">Option D</option>
</select>

JavaScript

/*
      Define the adapter so that it's reusable
*/         
$.fn.select2.amd.define('select2/selectAllAdapter', [
    'select2/utils',
    'select2/dropdown',
    'select2/dropdown/attachBody'
], function (Utils, Dropdown, AttachBody) {

    function SelectAll() { }
    SelectAll.prototype.render = function (decorated) {
        var self = this,
            $rendered = decorated.call(this),
            $selectAll = $(
                '<button class="btn btn-xs btn-default" type="button" style="margin-left:6px;"><i class="fa fa-check-square-o"></i> Select All</button>'
            ),
            $unselectAll = $(
                '<button class="btn btn-xs btn-default" type="button" style="margin-left:6px;"><i class="fa fa-square-o"></i> Unselect All</button>'
            ),
            $btnContainer = $('<div style="margin-top:3px;">').append($selectAll).append($unselectAll);
        if (!this.$element.prop("multiple")) {
            // this isn't a multi-select -> don't add the buttons!
            return $rendered;
        }
        $rendered.find('.select2-dropdown').prepend($btnContainer);
        $selectAll.on('click', function (e) {
            var $results = $rendered.find('.select2-results__option[aria-selected=false]');
            $results.each(function () {
                self.trigger('select', {
                    data: $(this).data('data')
                });
            });
            self.trigger('close');
        });
        $unselectAll.on('click', function (e) {
            var $results = $rendered.find('.select2-results__option[aria-selected=true]');
            $results.each(function () {
                self.trigger('unselect', {
                    data: $(this).data('data')
                });
            });
            self.trigger('close');
        });
        return $rendered;
    };

    return Utils.Decorate(
        Utils.Decorate(
            Dropdown,
            AttachBody
        ),
        SelectAll
   ...