# sectionSnapshotHandlers The diffable data source’s handlers for expanding and collapsing items. ``` @MainActor @preconcurrency var sectionSnapshotHandlers: UICollectionViewDiffableDataSource.SectionSnapshotHandlers { get set } ``` ## Discussion Provide section snapshot handlers to support the expanding or collapsing of items in your collection view. 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, currentChildSnapshot -> NSDiffableDataSourceSectionSnapshot in // Return child snapshot for the parent, or just currentChildSnapshot } ``` --- 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)