A basic implementation of a stack of cards tied to a model.

BaseStackView.swift

//
//  BaseStackView.swift
//  Sport Range
//
//  Created by Tal Atlas on 7/20/22.
//

import SwiftUI

class NavStack: ObservableObject {
    @Published
    var items: [StackContents] = []
}

struct StackContents: Identifiable {
    var id: UUID
    var color: Color
}

struct StackItemView: View {
    var content: StackContents
    
    @EnvironmentObject
    var navStack: NavStack
    
    var body: some View {
        VStack {
            Button("Add Child") {
                navStack.items.append(StackContents(id: UUID(), color: .gray))
            }
        }
            .frame(maxWidth: .infinity, maxHeight: .infinity)
            .background(content.color)
            .cornerRadius(36)
    }
}

struct BaseStackView: View {
    @StateObject
    var navStack = NavStack()
    
    var items: [StackContents] {
        navStack.items
    }

    @GestureState
    private var offset = CGSize.zero
    
    func Card(_ item: StackContents) -> some View {
        let isLast = item.id == items.last?.id
        return StackItemView(content: item)
            .scaleEffect(isLast ? 1 : 0.9)
            .offset(x: 0, y: isLast ? offset.height : 0)
            .gesture(
                DragGesture()
                    .updating($offset) { (value, state, transaction) in
                        guard isLast else { return }
                        state = value.translation
                    }
                    .onEnded { value in
                        if value.predictedEndTranslation.height > 200 {
                            navStack.items.removeLast()
                        }
                    }
                ,
                including: isLast ? .all : .none
            )
    }
    
    var body: some View {
        VStack {
            if items.isEmpty {
                Button("append - \(items.count)") {
                    navStack.items.append(.init(id: UUID(), color: .blue))
                }
            }
            else {
                ZStack(alignment: .top) {
                    ForEach(items) { item in
                        Card(item)
                            .transition(.move(edge: .bottom))
                    }
                }
            }
        }
        .environmentObject(navStack)
        .animation(.default.speed(1), value: items.count)
    }
}

struct BaseStackView_Previews: PreviewProvider {
    static var previews: some View {
        BaseStackView()
    }
}