BottomSheet.swift

import SwiftUI

struct ContentView: View {
    @State var show: Bool = false
    
    var body: some View {
        ZStack {
            Button {
                show.toggle()
            } label: {
                Text("Show")
            }
            
            ZStack(alignment: .bottom) {
                if show {
                    Color.clear
                    
                    Text("Hello once upon a time there was a duck named Ducky who went on to drink lots of juice boxes and live happily ever after")
                        .padding()
                        .frame(maxWidth: .infinity, alignment: .center)
                        .background(
                            Color.green
                                .cornerRadius(20.0)
                                .ignoresSafeArea()
                        )
                        .transition(.move(edge: .bottom))
                        .zIndex(1)
                }
            }
            .animation(.linear(duration: 1.0), value: show)
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

struct ContentView: View {
    @State var show: Bool = false
    
    var body: some View {
        ZStack {
            Button {
                show.toggle()
            } label: {
                Text("Show")
            }
            GeometryReader { reader in
                ZStack(alignment: .bottom) {
                    if show {
                        Color.clear
                        Text("Hello once upon a time there was a duck named Ducky who went on to drink lots of juice boxes and live happily ever after")
                            .padding()
                            .frame(maxWidth: .infinity, alignment: .center)
                            .padding(.bottom, reader.safeAreaInsets.bottom)
                            .background(
                                Color.green
                                    .cornerRadius(20.0)
                            )
                            .transition(.move(edge: .bottom))
                            .zIndex(1)
                    }
                }
                .ignoresSafeArea()
            }
            .animation(.linear(duration: 1.0), value: show)
        }
    }
}