DateFormatEditForm.php

<?php

namespace Drupal\system\Form;

use Drupal\Core\Form\FormStateInterface;

/**
 * Provides a form for editing a date format.
 *
 * @internal
 */
class DateFormatEditForm extends DateFormatFormBase {
    
    /**
     * {@inheritdoc}
     */
    public function form(array $form, FormStateInterface $form_state) {
        $form = parent::form($form, $form_state);
        $now = t('Displayed as %date', [
            '%date' => $this->dateFormatter
                ->format(REQUEST_TIME, $this->entity
                ->id()),
        ]);
        $form['date_format_pattern']['#field_suffix'] = ' <small data-drupal-date-formatter="preview">' . $now . '</small>';
        $form['date_format_pattern']['#default_value'] = $this->entity
            ->getPattern();
        return $form;
    }
    
    /**
     * {@inheritdoc}
     */
    protected function actions(array $form, FormStateInterface $form_state) {
        $actions = parent::actions($form, $form_state);
        $actions['submit']['#value'] = t('Save format');
        unset($actions['delete']);
        return $actions;
    }

}