The data definition of a field item. Type:

public BaseFieldDefinition::setCustomStorage($custom_storage)

public FormatterInterface::settingsSummary()

protected FieldStorageConfig::preSaveNew(EntityStorageInterface

public BaseFieldDefinition::getTargetEntityTypeId()

public FieldStorageDefinitionListener

public FieldStorageConfig::preSave(EntityStorageInterface

public FieldConfigBase::getItemDefinition()

Validates module uninstall readiness based on defined storage definitions. @todo Remove this once we support field purging for base fields.

public FieldItemListInterface::deleteRevision()