Add dragDroppingItems to accumulate changes & update dragDropConfig.dataBinding only once per drag-drop reorder

Sources/ASCollectionView/Implementation/ASCollectionView.swift

@@ -794,6 +794,10 @@ public struct ASCollectionView<SectionID: Hashable>: UIViewControllerRepresentab
 			guard let oldSnapshot = dataSource?.currentSnapshot else { return }
 			var dragSnapshot = oldSnapshot
 
+			parent.sections.forEach { section in
+				section.dataSource.applyPrepare()
+			}
+
 			switch coordinator.proposal.operation
 			{
 			case .move:
@@ -864,6 +868,10 @@ public struct ASCollectionView<SectionID: Hashable>: UIViewControllerRepresentab
 			default: break
 			}
 
+			parent.sections.forEach { section in
+				section.dataSource.applyCommit()
+			}
+
 			if let dragItem = coordinator.items.first, let destination = coordinator.destinationIndexPath
 			{
 				if dragItem.sourceIndexPath != nil

Sources/ASCollectionView/Implementation/ASSectionDataSource.swift

@@ -23,9 +23,11 @@ internal protocol ASSectionDataSourceProtocol
 	func getItemID<SectionID: Hashable>(for dragItem: UIDragItem, withSectionID sectionID: SectionID) -> ASCollectionViewItemUniqueID?
 	func supportsMove(_ indexPath: IndexPath) -> Bool
 	func supportsMove(from sourceIndexPath: IndexPath, to destinationIndexPath: IndexPath) -> Bool
+	func applyPrepare()
 	func applyMove(from: IndexPath, to: IndexPath) -> Bool
 	func applyRemove(atOffsets offsets: IndexSet)
 	func applyInsert(items: [UIDragItem], at index: Int) -> Bool
+	func applyCommit()
 	func supportsDelete(at indexPath: IndexPath) -> Bool
 	func onDelete(indexPath: IndexPath) -> Bool
 	func getContextMenu(for indexPath: IndexPath) -> UIContextMenuConfiguration?
@@ -98,6 +100,12 @@ internal struct ASSectionDataSource<DataCollection: RandomAccessCollection, Data
 
 	var supplementaryViews: [String: AnyView] = [:]
 
+	/// Temporal boxed storage for not setting `dragDropConfig.dataBinding.wrappedValue`
+	/// multiple times during Drap & Drop.
+	/// For example, by having this storage, reordering 3 items will invoke "3 items -> 3 items" only once,
+	/// not "3 items --(removed)--> 2 items --(inserted)--> 3 items".
+	private let dragDroppingItems: Box<[DataCollection.Element]?> = Box(nil)
+
 	var dragEnabled: Bool { dragDropConfig.dragEnabled }
 	var dropEnabled: Bool { dragDropConfig.dropEnabled }
 	var reorderingEnabled: Bool { dragDropConfig.reorderingEnabled }
@@ -257,6 +265,11 @@ internal struct ASSectionDataSource<DataCollection: RandomAccessCollection, Data
 		dragDropConfig.reorderingEnabled && (dragDropConfig.canMoveItem?(sourceIndexPath, destinationIndexPath) ?? true)
 	}
 
+	func applyPrepare()
+	{
+		dragDroppingItems.value = dragDropConfig.dataBinding?.wrappedValue
+	}
+
 	func applyMove(from: IndexPath, to: IndexPath) -> Bool
 	{
 		// dragDropConfig.dataBinding?.wrappedValue.move(fromOffsets: [from], toOffset: to) //This is not behaving as expected
@@ -280,9 +293,10 @@ internal struct ASSectionDataSource<DataCollection: RandomAccessCollection, Data
 
 	func applyRemove(atOffsets offsets: IndexSet)
 	{
-		if let binding = dragDropConfig.dataBinding
+		if var items = dragDroppingItems.value
 		{
-			binding.wrappedValue.remove(atOffsets: offsets)
+			items.remove(atOffsets: offsets)
+			dragDroppingItems.value = items
 		}
 		else
 		{
@@ -293,15 +307,16 @@ internal struct ASSectionDataSource<DataCollection: RandomAccessCollection, Data
 	func applyInsert(items: [UIDragItem], at index: Int) -> Bool
 	{
 		let actualItems = items.compactMap(getDropItem(from:))
-		if let binding = dragDropConfig.dataBinding
+		if var items = dragDroppingItems.value
 		{
-			let allDataIDs = Set(binding.wrappedValue.map { $0[keyPath: dataIDKeyPath] })
+			let allDataIDs = Set(items.map { $0[keyPath: dataIDKeyPath] })
 			let noDuplicates = actualItems.filter { !allDataIDs.contains($0[keyPath: dataIDKeyPath]) }
 #if DEBUG
 			// Notify during debug build if IDs are not unique (programmer error)
 			if noDuplicates.count != actualItems.count { print("ASCOLLECTIONVIEW/ASTABLEVIEW: Attempted to insert an item with the same ID as one already in the section. This may cause unexpected behaviour.") }
 #endif
-			binding.wrappedValue.insert(contentsOf: noDuplicates, at: index)
+			items.insert(contentsOf: noDuplicates, at: index)
+			dragDroppingItems.value = items
 			return !noDuplicates.isEmpty
 		}
 		else
@@ -310,6 +325,11 @@ internal struct ASSectionDataSource<DataCollection: RandomAccessCollection, Data
 		}
 	}
 
+	func applyCommit()
+	{
+		dragDropConfig.dataBinding?.wrappedValue = dragDroppingItems.value ?? []
+	}
+
 	func getContextMenu(for indexPath: IndexPath) -> UIContextMenuConfiguration?
 	{
 		guard
@@ -437,3 +457,14 @@ internal extension ASSectionDataSource
 		selfSizingConfig = config
 	}
 }
+
+// MARK: - Box
+
+private class Box<T>
+{
+	var value: T
+
+	init(_ value: T) {
+		self.value = value
+	}
+}

Sources/ASCollectionView/Implementation/ASTableView.swift

@@ -645,6 +645,10 @@ public struct ASTableView<SectionID: Hashable>: UIViewControllerRepresentable, C
 			guard let oldSnapshot = dataSource?.currentSnapshot else { return }
 			var dragSnapshot = oldSnapshot
 
+			parent.sections.forEach { section in
+				section.dataSource.applyPrepare()
+			}
+
 			switch coordinator.proposal.operation
 			{
 			case .move:
@@ -715,6 +719,10 @@ public struct ASTableView<SectionID: Hashable>: UIViewControllerRepresentable, C
 			default: break
 			}
 
+			parent.sections.forEach { section in
+				section.dataSource.applyCommit()
+			}
+
 			dataSource?.applySnapshot(dragSnapshot, animated: false)
 			refreshVisibleCells(transaction: nil)
 			if let dragItem = coordinator.items.first, let destination = coordinator.destinationIndexPath