How do I sort my NSSet Array for date added in SwiftUI?

Question

This is my Group+CoreDataProperty. I am currently sorting alphabetically with postName. Now I want to sort by date added. how do I change this?

extension Group {

    @nonobjc public class func fetchRequest() -> NSFetchRequest<Group> {
        return NSFetchRequest<Group>(entityName: "Group")
    }

    @NSManaged public var groupThumbnail: Data?
    @NSManaged public var groupTitle: String?
    @NSManaged public var home: Home?
    @NSManaged public var posts: NSSet?

    public var postsArr: [Post] {
        let set = posts as? Set<Post> ?? []
        return set.sorted {
            $0.postName ?? "" < $1.postName ?? ""
        }
    }
}

I have tried to replace $0.postName ?? "" < $1.postName ?? "" with:

$0.postDate ?? "" < $1.postDate ?? "". But what do I replace "" with?

Thanks for any help!

Answer 1

If postDate is of type Date you can do

        $0.postDate ?? Date() < $1.postDate ?? Date()

The value after ?? defines what is used when the primary value is nil, so it always has to match the type of the original attribute. When String it has to be a string, e.g. "", when Date it has to be a Date. Date() would return the current date if the value is nil – which shouldn't be the case anyway.