SwiftUI: Chooseable ViewModifier to use fullScreenCover and sheet modal at the same time.

OptionalSheet.swift

// MARK: - Modifier

/// Choosable Sheet for FullScreen or Sheet Modal
struct ChooseableSheet<Destination>: ViewModifier where Destination: View {
    
    // Select it's fullscreen sheet or modal sheet
    @Binding var isFullScreen: Bool
  
    @Binding var isPresented: Bool
    private let fullScreenContent: () -> Destination?
    private let modalContent: () -> Destination?
    
    init(
        isFullScreen: Binding<Bool>,
        isPresented: Binding<Bool>,
        @ViewBuilder fullScreenContent: @escaping () -> Destination? = { nil },
        @ViewBuilder modalContent: @escaping () -> Destination? = { nil }
    ) {
        self._isFullScreen = isFullScreen
        self._isPresented = isPresented
        self.fullScreenContent = fullScreenContent
        self.modalContent = modalContent
    }
    
    func body(content: Content) -> some View {
        if isFullScreen {
            return AnyView(
                content
                    .fullScreenCover(isPresented: $isPresented) {
                        fullScreenContent()
                    }
            )
        } else {
            return AnyView(
                content
                    .sheet(isPresented: $isPresented) {
                        modalContent()
                    }
            )
        }
    }
    
}

// MAKR: - Useage

struct MyView: View {
    
    @State private var isFullScreen: Bool = false
    @State private var isPresented: Bool = false
    
    var body: some View {
        ZStack {
            
            Button(action: {
                isFullScreen.toggle()
                isPresented.toggle()
            }) {
                Text("Toggle FullScreen / Modal")
            }
            
        }
        .modifier(
            ChooseableSheet(
                isFullScreen: $isFullScreen,
                isPresented: $isPresented,
                fullScreenContent: { getFullScreenContent() },
                modalContent: { getSheetContent() }
            )
        )
        
    }
    
    @ViewBuilder
    private func getFullScreenContent() -> AnyView {
        AnyView(
            Text("Full Screen")
        )
    }
    
    @ViewBuilder
    private func getSheetContent() -> AnyView {
        AnyView(
            VStack {
                Text("Sheet Model")
            }
        )
    }
    
}