SwiftData predicate filtered by enum case

Question

Created 6d

Replies 4

Boosts 2

Participants 3

This post is from the WWDC26 SwiftData Q&A.

I have several Swift Data types with a property of type enum. Whenever I've tried to write a predicate returning data objects only of a certain enum case, the compiler throws an error from the macro at build time. (which I don't have handy, sorry...). Is this supported? And if so, how would you write the predicate?

@Model
public final class AlbumList {
    // ...
    public var listType: AlbumListType
    // ...
}

public enum AlbumListType: String, CaseIterable, Codable {
    case listener
    case dj
}

Answered by Frameworks Engineer in 891882022

To fetch all AlbumList models whose listType is AlbumListType.listener, the predicate would be:

let target = AlbumListType.listener
let predicate = #Predicate<AlbumList> { $0.listType == target }

Note that the right-hand side is declared on its own line and captured. Putting AlbumListType.listener directly in the builder closure may lead to an error from the macro.

Answer 1

Frameworks Engineer OP

Apple

6d

Accepted Answer

Recommended

To fetch all AlbumList models whose listType is AlbumListType.listener, the predicate would be:

let target = AlbumListType.listener
let predicate = #Predicate<AlbumList> { $0.listType == target }

Note that the right-hand side is declared on its own line and captured. Putting AlbumListType.listener directly in the builder closure may lead to an error from the macro.

Answer 2

bondad OP

6d

@Frameworks Engineer thank you so much!! I figured there had to be a way

Answer 3

alpennec OP

4d

@Frameworks Engineer thank you for sharing that!

Does this only work for the new anyAppleOS 27 and not before (like iOS 17/18/26)?

Thanks

Axel

Answer 4

alpennec OP

3d

I just tested using an Enum in a SwiftData Query Predicate only works for anyAppleOS 27 & doesn't back deploy when building on Xcode 27 🫤

On anyAppleOS 26 & below, Xcode logs "Query encountered an error: Unsupported Predicate: Captured/constant values of type 'TheEnum' are not supported"

@Frameworks Engineer do you think there is any chance to back deploy that to prior OS versions?

Thank you.