# snapshotForExpandingParent The handler that provides the section snapshot for expanding the parent item. ``` var snapshotForExpandingParent: ((ItemIdentifierType, NSDiffableDataSourceSectionSnapshot) -> NSDiffableDataSourceSectionSnapshot)? { get set } ``` ## Discussion Use the [`snapshotForExpandingParent`](/documentation/UIKit/UICollectionViewDiffableDataSource-9tqpa/SectionSnapshotHandlers-swift.struct/snapshotForExpandingParent) handler to customize the snapshot that returns when a particular parent item is expanded. ```swift // Allow every item to be collapsed dataSource.sectionSnapshotHandlers.shouldCollapseItem = { item in return true } dataSource.sectionSnapshotHandlers.snapshotForExpandingParent = { parent, existingSnapshot -> NSDiffableDataSourceSectionSnapshot in // Return child snapshot for the parent, or just existingSnapshot } ``` --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)