synchronizeFields example

function hook_entity_presave(\Drupal\Core\Entity\EntityInterface $entity) {
  if ($entity instanceof ContentEntityInterface && $entity->isTranslatable()) {
    $route_match = \Drupal::routeMatch();
    \Drupal::service('content_translation.synchronizer')->synchronizeFields($entity, $entity->language()->getId(), $route_match->getParameter('source_langcode'));
  }
}

/** * Act on a specific type of entity before it is created or updated. * * You can get the original entity object from $entity->original when it is an * update of the entity. * * @param \Drupal\Core\Entity\EntityInterface $entity * The entity object. * * @ingroup entity_crud * @see hook_entity_presave() */