JsDeprecationTestController.php

<?php

declare (strict_types=1);
namespace Drupal\js_deprecation_test\Controller;


/**
 * Test Controller to show message links.
 */
class JsDeprecationTestController {
  
  /**
   * Renders page that has js_deprecation_test/deprecation library attached.
   *
   * @return array
   *   Render array.
   */
  public function jsDeprecationTest() {
    return [
      '#attached' => [
        'library' => [
          'js_deprecation_test/deprecation_test',
        ],
      ],
    ];
  }

}