SwiftData predicate filtered by enum case

Question

Created 16h

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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

15h

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

15h

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