collapsing navigation stacks in swiftUI

CollapsableView.swift

import SwiftUI

struct FirstDetailView: View {
    @EnvironmentObject var nav: NavigationController
    var body: some View {
        VStack {
            Text("Whaterever")
            Button(action: {
                self.nav.detailIsShown = false
            }) {
                Text("go back to the begining")
            }
        }
    }
}