@DataStorage

Makes it easy to work with Data.

No args

@DataStorage
struct DataHolder {}

Expands to:

struct DataHolder {
    let data: Data
    
    init(data: Data) {
        self.data = data
    }
}

byteCount

@DataStorage(named: "key", byteCount: 32)
public struct PublicKey {}

Expands to:

public struct PublicKey {
    public static let byteCount = 32
    public let key: Data
    
    public init(key: Data) throws {
        guard key.count == Self.byteCount else {
            throw InvalidByteCount(actual: key.count)
        }
        self.key = key
    }
}

extension PubliKey {
    struct InvalidByteCount: Swift.Error, CustomStringConvertible {
        let actual: Int
        var description: String {
            "Invalid byteCount, expected: \(PublicKey.byteCount), but got: \(actual)"
        }
    }
}