SwiftUI, extension sample

 

struct HiddenNavigationBar: ViewModifier {
    func body(content: Content) -> some View {
        content
        .navigationBarTitle("", displayMode: .inline)
        .navigationBarHidden(true)
    }
}

extension View {
    func hiddenNavigationBarStyle() -> some View {
        modifier( HiddenNavigationBar() )
    }
}

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.hiddenNavigationBarStyle()

REF : https://www.hackingwithswift.com/forums/swiftui/removing-unwanted-and-unknown-whitespace-possibly-a-navigation-bar-above-a-view/7343