PopToRootViewModifier.swift

import SwiftUI

final class NavigationManager: ObservableObject {
    var canPopToRootView: Bool // NB: this must not be @Published

    init() {
        self.canPopToRootView = true
    }
}

private struct PopToRootViewModifier<T>: ViewModifier {
    @EnvironmentObject private var navigationManager: NavigationManager

    @Binding var binding: T?
    let visibleAction: (() -> Void)

    init(ifVisible visibleAction: @escaping (() -> Void),
         elseReset binding: Binding<T?>) {
        self.visibleAction = visibleAction
        self._binding = binding
    }

    private func resetBinding() {
        if self.navigationManager.canPopToRootView {
            withAnimation(nil) {
                self.binding = nil
            }
        }
    }
    
    func body(content: Content) -> some View {
        content
            .onReselect(ifVisible: visibleAction, else: self.resetBinding)
    }
}

extension View {
    public func onReselect<T>(ifVisible visibleAction: @escaping (() -> Void),
                              elseReset binding: Binding<T?>) -> some View {
        return self.modifier(PopToRootViewModifier(ifVisible: visibleAction, elseReset: binding))
    }
}