JsErrorsTestController.php

<?php

namespace Drupal\js_errors_test\Controller;


/**
 * Test Controller loading js_errors_test/errors_test library.
 */
class JsErrorsTestController {
    
    /**
     * Renders page that has js_errors_test/errors_test library attached.
     *
     * @return string[][]
     *   Render array.
     */
    public function jsErrorsTest() : array {
        return [
            '#attached' => [
                'library' => [
                    'js_errors_test/errors_test',
                ],
            ],
        ];
    }

}