JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://hemantnegi.github.io/jquery.sumoselect/javascripts/jquery.sumoselect.min.js"></script>
<link rel="stylesheet" href="https://hemantnegi.github.io/jquery.sumoselect/stylesheets/sumoselect.css">
<select multiple="multiple" class="testSelAll">
  <option value="car1">Volvo</option>
  <option value="car2">Saab</option>
  <option value="car3">Mercedes</option>
  <option value="car4">Audi</option>
</select>

JavaScript

$(document).ready(function() {
  $('.testSelAll').SumoSelect({
    okCancelInMulti: true,
    selectAll: true
  });

  $('.btnOk').on('click', function() {
    var obj = [],
    		items = '';
    $('.testSelAll option:selected').each(function(i) {
    	obj.push($(this).val());
      $('.testSelAll')[0].sumo.unSelectItem(i);
    });
    for(var i=0;i<obj.length;i++) {items += ' ' + obj[i]};
    alert(items);
  });
});