jasaraharja/public/vendor/select2-bootstrap4-theme-ma.../docs/script.js

$(function () {
  $('select').each(function () {
    $(this).select2({
      theme: 'bootstrap4',
      width: 'style',
      placeholder: $(this).attr('placeholder'),
      allowClear: Boolean($(this).data('allow-clear')),
    });
  });
});