نشكل عرض في SwiftUI ، انطلاقا من الشروط

struct HomeView: View {
    @ObservedObject var loginManager: LoginManager

    var body: some View {
        VStack {
            if let user = loginManager.loggedInUser {
                ProfileView(user: user)
            }

            ...
        }
    }
}

لا يمكن استخدام الإغلاق الذي يحتوي على بيان تدفق التحكم مع منشئ الوظائف ViewBuilder.

struct ProfileView: View {
    var user: User?

    var body: some View {
        guard let user = user else {
            // We have to use 'AnyView' to perform type erasure here,
            // in order to give our 'body' a single return type:
            return AnyView(EmptyView())
        }

        return AnyView(VStack {
            Text(user.name)
            ...
        })
    }
}

struct HomeView: View {
    @ObservedObject var loginManager: LoginManager

    var body: some View {
        VStack {
            loginManager.loggedInUser.map { user in
                ProfileView(user: user)
            }
            ...
        }
    }
}

struct Unwrap<Value, Content: View>: View {
    private let value: Value?
    private let contentProvider: (Value) -> Content

    init(_ value: Value?,
         @ViewBuilder content: @escaping (Value) -> Content) {
        self.value = value
        self.contentProvider = content
    }

    var body: some View {
        value.map(contentProvider)
    }
}

struct HomeView: View {
    @ObservedObject var loginManager: LoginManager

    var body: some View {
        VStack {
            Unwrap(loginManager.loggedInUser) { user in
                HStack {
                    Text("Logged in as:")
                    ProfileView(user: user)
                }
            }
            ...
        }
    }
}