Ajax callback select2, radios field

ajax_callback_select2_radios.php

<?php

namespace Drupal\nh_phahe\Service;

use Drupal\Component\Utility\NestedArray;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\StringTranslation\StringTranslationTrait;
use Drupal\node\Entity\Node;

/**
 * Form service support.
 *
 * @package Drupal\nh_phahe\Service
 */
class FormService {

  use StringTranslationTrait;

  public function registerFormAlter(&$form, FormStateInterface $form_state) {
    $options = [];
    $field_ten_cha = $form_state->getValue('field_ten_cha');
    if ($field_ten_cha && $reference_id = NestedArray::getValue($field_ten_cha, [
        '0',
        'target_id',
      ])) {
      $query = \Drupal::entityQuery('node')->condition('type', 'pha_he');
      $query->condition('field_ten_cha', $reference_id);
      $node_ids = $query->execute();
      $nodes = Node::loadMultiple($node_ids);
      foreach ((array) $nodes as $node) {
        $options[$node->id()] = $node->label();
      }
    }
    $form['con_fieldset'] = [
      '#type' => 'fieldset',
      '#tree' => FALSE,
      '#title' => $this->t('Danh sách con'),
      '#prefix' => '<div id="phahe_con_wrapper">',
      '#suffix' => '</div>',
    ];

    $form['con_fieldset']['con'] = [
      '#type' => 'radios',
      '#required' => FALSE,
      '#options' => $options,
    ];
    
    $form['field_ten_cha']['widget']['#ajax'] = [
      'callback' => [self::class, 'ajaxCallback'],
      'wrapper' => 'phahe_con_wrapper',
      'event' => 'select2:close',
    ];

    // Attach library
    // $form['#attached']['library'][] = 'nh_phahe/register';
  }

  public static function ajaxCallback($form, FormStateInterface $form_state) {
    return $form['con_fieldset'];
  }

}