exportingCondition(_:)

Declaration

func exportingCondition(_ condition: @escaping  @Sendable (Self.Item) -> Bool) -> _ConditionalTransferRepresentation<Self>

Parameters

• condition:

  A closure that determines whether the item is exportable. Don’t perform long-running work in this closure. It shouldn’t contain network requests, file operations, or other potentially time-consuming tasks as they can cause delays during operations with Transferable items.

Discussion

Some instances of a model type may have state-dependent conditions that make them unsuitable for export. For example, an Archive structure that supports a comma-separated text representation only when it has compatible content:

struct Archive {
    var supportsCSV: Bool
    func csvData() -> Data
    init(csvData: Data)
}

extension Archive: Transferable {
    static var transferRepresentation: some TransferRepresentation {
        DataRepresentation(contentType: .commaSeparatedText) { archive in
            archive.csvData()
        } importing: { data in Archive(csvData: data) }
            .exportingCondition { archive in archive.supportsCSV }
    }
}