datafield-1.x-dev/src/Plugin/DataField/FieldFormatter/MailToFormatter.php

<?php

namespace Drupal\datafield\Plugin\DataField\FieldFormatter;

use Drupal\Core\Field\Attribute\FieldFormatter;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\StringTranslation\TranslatableMarkup;
use Drupal\Core\Url;
use Drupal\datafield\Plugin\DataFieldFormatterInterface;

/**
 * Plugin implementation of the 'email_mailto' formatter.
 */
#[FieldFormatter(
  id: 'email_mailto',
  label: new TranslatableMarkup('Email'),
  field_types: ['email'],
)]
class MailToFormatter implements DataFieldFormatterInterface {

  /**
   * {@inheritdoc}
   */
  public function viewElements($item, $langcode) {
    if (is_null($item->value)) {
      return $item->value;
    }
    return [
      '#type' => 'link',
      '#title' => $item->value,
      '#url' => Url::fromUri('mailto:' . $item->value),
    ];
  }

  /**
   * {@inheritdoc}
   */
  public function settingsForm(array $form, FormStateInterface $form_state) {
    return [];
  }

  /**
   * {@inheritdoc}
   */
  public function settingsSummary($settings = []) {
    return [];
  }

}