ManagedObjectContextChanges.swift

private var cancellables = [AnyCancellable]()

let cancellable = NotificationCenter.default.publisher(for: .NSManagedObjectContextObjectsDidChange, object: managedObjectContext)
	.compactMap({ ManagedObjectContextChanges<ColorItem>(notification: $0) }).sink { (changes) in
		print(changes)
	}
cancellables.append(cancellable)

struct ManagedObjectContextChanges<T: NSManagedObject> {
	let inserted: Set<T>
	let deleted: Set<T>
	let updated: Set<T>
    
	init?(notification: Notification) {
		let unpack: (String) -> Set<T> = { key in
			let managedObjects = (notification.userInfo?[key] as? Set<NSManagedObject>) ?? []
			return Set(managedObjects.compactMap({ $0 as? T }))
		}
		deleted = unpack(NSDeletedObjectsKey)
		inserted = unpack(NSInsertedObjectsKey)
		updated = unpack(NSUpdatedObjectsKey).union(unpack(NSRefreshedObjectsKey))
		if deleted.isEmpty, inserted.isEmpty, updated.isEmpty {
			return nil
		}
	}
}