EntityTestUpdateStorageSchema.php

<?php

namespace Drupal\entity_test_update;

use Drupal\Core\Entity\ContentEntityTypeInterface;
use Drupal\Core\Entity\Sql\SqlContentEntityStorageSchema;
use Drupal\Core\Field\FieldStorageDefinitionInterface;

/**
 * Defines the entity_test_update storage_schema handler.
 */
class EntityTestUpdateStorageSchema extends SqlContentEntityStorageSchema {
    
    /**
     * {@inheritdoc}
     */
    protected function getEntitySchema(ContentEntityTypeInterface $entity_type, $reset = FALSE) {
        $schema = parent::getEntitySchema($entity_type, $reset);
        if ($entity_type->id() == 'entity_test_update') {
            $schema[$this->storage
                ->getBaseTable()]['indexes'] += \Drupal::state()->get('entity_test_update.additional_entity_indexes', []);
        }
        return $schema;
    }
    
    /**
     * {@inheritdoc}
     */
    protected function getSharedTableFieldSchema(FieldStorageDefinitionInterface $storage_definition, $table_name, array $column_mapping) {
        $schema = parent::getSharedTableFieldSchema($storage_definition, $table_name, $column_mapping);
        if (\Drupal::state()->get('entity_test_update.additional_field_index.' . $table_name . '.' . $storage_definition->getName())) {
            $this->addSharedTableFieldIndex($storage_definition, $schema);
        }
        return $schema;
    }

}