select2.install

<?php

/**
 * @file
 * This is the Select2 module.
 */

/**
 * Implements hook_requirements().
 */
function select2_requirements(string $phase): array {
  $requirements = [];
  if ($phase !== 'runtime') {
    return [];
  }

  $requirements['select2'] = [
    'title' => 'select2',
    'value' => t('Select2 library found'),
    'severity' => REQUIREMENT_OK,
  ];

  if (\Drupal::service('library.libraries_directory_file_finder')->find('select2')) {
    return $requirements;
  }

  if (file_exists(\Drupal::service('library.discovery')->getLibraryByName('select2', 'select2.min')['js'][0]['data'])) {
    return $requirements;
  }

  return [
    'select2' => [
      'title' => 'select2',
      'value' => t("Select2 library doesn't exists"),
      'description' => t('Make sure that the select2 lib is placed in the library folder. You can download the release of your choice from <a href=":link" target="_blank">GitHub</a>.', [':link' => 'https://github.com/select2/select2/tags']),
      'severity' => REQUIREMENT_ERROR,
    ],
  ];
}