snapshotForExpandingParentItemHandler
The handler that provides the section snapshot for expanding the parent item.
Declaration
@property (nonatomic, copy) NSDiffableDataSourceSectionSnapshot<id> * (^snapshotForExpandingParentItemHandler)(ItemType , NSDiffableDataSourceSectionSnapshot<id> *);Discussion
Use the snapshotForExpandingParentItemHandler handler to customize the snapshot that returns when a particular parent item is expanded.
// Allow every item to be collapsed
dataSource.sectionSnapshotHandlers.shouldCollapseItem = { item in return true }
dataSource.sectionSnapshotHandlers.snapshotForExpandingParent = {
parent, existingSnapshot -> NSDiffableDataSourceSectionSnapshot<String> in
// Return child snapshot for the parent, or just existingSnapshot
}