class MachineName

class MachineName extends ProcessPluginBase implements ContainerFactoryPluginInterface {

  /**
   * The transliteration service.
   *
   * @var \Drupal\Component\Transliteration\TransliterationInterface
   */
  protected $transliteration;

  /**
   * The regular expression pattern.
   *
   * @var string
   */
  protected $replacePattern;

  /**
   * Constructs a MachineName plugin.
   *
   * @param array $configuration
   *   The plugin configuration.
   * @param string $plugin_id
   *   The plugin ID.
   * @param mixed $plugin_definition
   *   The plugin definition.
   * @param \Drupal\Component\Transliteration\TransliterationInterface $transliteration
   *   The transliteration service.
   */
  public function __construct(array $configuration, $plugin_id, $plugin_definition, TransliterationInterface $transliteration) {
    parent::__construct($configuration, $plugin_id, $plugin_definition);
    $this->transliteration = $transliteration;
    $this->replacePattern = $this->configuration['replace_pattern'] ?? '/[^a-z0-9_]+/';
    if (!is_string($this->replacePattern)) {
      throw new MigrateException('The replace pattern should be a string');
    }
  }

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
    return new static($configuration, $plugin_id, $plugin_definition, $container
      ->get('transliteration'));
  }

  /**
   * {@inheritdoc}
   */
  public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
    $new_value = $this->transliteration
      ->transliterate($value, LanguageInterface::LANGCODE_DEFAULT, '_');
    $new_value = strtolower($new_value);
    $new_value = preg_replace($this->replacePattern, '_', $new_value);
    return preg_replace('/_+/', '_', $new_value);
  }

}