Realm and Diffable Data Source

Question

Has anyone tried to use Realm in conjunction with diffable data sources? There seems to be an issue I can't get my head around.

So, when when we use the "traditional" data source API, in cellForRowAt we get the object for a particular row on an index-based basis and since Realm returns objects inside its generic Results type (e.g. let items = Results<Item>), which conforms to Collection, we can basically access the element like always: items[indexPath.row]

However, when you use diffable data source and create a snapshot, you have it like this: var snapshot = NSDiffableDataSourceSnapshot<Int, Item>. You add a section by doing snapshot.appendSections([0]) and then you have to add items to that section. My main issue here is that you can't do snapshot.appendItems(items) since items is of type Results<Item>, not Array<Item>. Am I missing something here?

Also, Realm's Object class seems to have its own implementation of Hashable so I think there's no way of ensuring the uniqueness of objects apart from overriding Realm's primaryKey and implementing your own auto increment feature. All that seems a bit weird to me to the point where I'm thinking to switch to Core Data.

Haven't found similar topics on StackOverflow so any help will be much appreciated.

Answer 1

You can covert Result<Items> to Array using an extension:

extension Results {
  func toArray() -> [Element] {
    return compactMap {
        $0
    }
  }
}

You can use it like: results.toArray() and it will give you the array and then with your case you can append data into it.