import SwiftUI

public struct UnwrapView<Some: View, None: View>: View {

    private let some: () -> Some?
    private let none: () -> None?

    public init<Value>(value: Value?,
                       some: @escaping (Value) -> Some,
                       none: @escaping () -> None) {

        self.some = { value.map(some) }
        self.none = { value == nil ? none() : nil }
    }

    public var body: some View {
        Group {
            some()
            none()
        }
    }
}


struct UnwrapView_Previews: PreviewProvider {

    static var previews: some View {
        Group {

            UnwrapView(value: "Some",
                       some: Text.init,
                       none: { Color.red })
                .previewLayout(.fixed(width: 200, height: 50))
                .previewDisplayName("some")

            UnwrapView(value: nil,
                       some: Text.init,
                       none: { Color.red })
                .previewLayout(.fixed(width: 200, height: 50))
                .previewDisplayName("none")
        }
    }
}