import Foundation final class ThumbnailsModel: ObservableObject { @Published var unloadable = Set() func insertUnloadable(_ url: URL) { unloadable.insert(url) } func isUnloadable(_ url: URL!) -> Bool { guard !url.isNil else { return true } return unloadable.contains(url) } func loadableURL(_ url: URL!) -> URL? { guard !url.isNil else { return nil } return isUnloadable(url) ? nil : url } }