Update UICollectionView based on before and after arrays

UICollectionView+batchUpdate.swift

extension UICollectionView {
	///Perform batch update based on before and after arrays
	///An array must not contain duplicate values
	func batchUpdate<T: Equatable>(section: Int, from oldData: [T], to newData: [T], completion: ((Bool) -> Void)? = nil) {
		performBatchUpdates({
			let deletions = oldData.indices.filter { !newData.contains(oldData[$0]) }
			deleteItems(at: deletions.map { IndexPath(item: $0, section: section) })
			
			let insertions = newData.indices.filter { !oldData.contains(newData[$0]) }
			insertItems(at: insertions.map { IndexPath(item: $0, section: section) })
			
			for (oldIndex, value) in oldData.enumerated() {
				if let newIndex = newData.firstIndex(of: value) {
					assert(newIndex == newData.lastIndex(of: value))
					moveItem(at: IndexPath(item: oldIndex, section: section), to: IndexPath(item: newIndex, section: section))
				}
			}
		}, completion: completion)
	}
}