class ConfigEntityNormalizer

class ConfigEntityNormalizer extends EntityNormalizer {
    
    /**
     * {@inheritdoc}
     */
    protected $supportedInterfaceOrClass = ConfigEntityInterface::class;
    
    /**
     * {@inheritdoc}
     */
    public function normalize($object, $format = NULL, array $context = []) {
        return static::getDataWithoutInternals($object->toArray());
    }
    
    /**
     * {@inheritdoc}
     */
    public function denormalize($data, $class, $format = NULL, array $context = []) {
        return parent::denormalize(static::getDataWithoutInternals($data), $class, $format, $context);
    }
    
    /**
     * Gets the given data without the internal implementation details.
     *
     * @param array $data
     *   The data that is either currently or about to be stored in configuration.
     *
     * @return array
     *   The same data, but without internals. Currently, that is only the '_core'
     *   key, which is reserved by Drupal core to handle complex edge cases
     *   correctly. Data in the '_core' key is irrelevant to clients reading
     *   configuration, and is not allowed to be set by clients writing
     *   configuration: it is for Drupal core only, and managed by Drupal core.
     *
     * @see https://www.drupal.org/node/2653358
     */
    protected static function getDataWithoutInternals(array $data) {
        return array_diff_key($data, [
            '_core' => TRUE,
        ]);
    }

}