Source code for CodeSlicing episode on demystifying property wrappers part 1

StateAndBindingDemo.swift

//
//  StateAndBindingDemo.swift
//
//  Permission is hereby granted, free of charge, to any person obtaining a copy
//  of this software and associated documentation files (the "Software"), to deal
//  in the Software without restriction, including without limitation the rights
//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
//  of the Software, and to permit persons to whom the Software is furnished to do so,
//  subject to the following conditions:
//
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
//  INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
//  PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
//  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
//  AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
//  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
//  Created by Adam Fordyce on 27/03/2021.
//  Copyright © 2020 Adam Fordyce. All rights reserved.
//

import SwiftUI
import PureSwiftUI

struct StateAndBindingDemo: View {
    
    private let _counter = State(initialValue: 0)
    
    private var counter: Int {
        _counter.wrappedValue
    }
    
    private var _$counter: Binding<Int> {
        _counter.projectedValue
    }
    
    var body: some View {
        VStack(spacing: 50) {
            TitleText("Current count: \(counter)")
            CounterUpdatingButton(counter: _$counter)
        }
    }
}

private struct CounterUpdatingButton: View {
    
    let counter: Binding<Int>
    
    var body: some View {
        VStack {
            Button {
                counter.wrappedValue += 1
            } label: {
                TitleText("Increment")
                    .shadow(2)
                    .padding()
                    .clipCapsuleWithStroke(Color.white, lineWidth: 2,
                                           fill: LinearGradient([.red, .orange], to: .bottomTrailing))
            }
        }
    }
}

struct BindingDemo_Previews: PreviewProvider {
    struct BindingDemo_Harness: View {

        var body: some View {
            StateAndBindingDemo()
                .greedyFrame()
                .foregroundColor(.white)
                .backgroundColor(.white(0.1))
                .ignoresSafeArea()
        }
    }

    static var previews: some View {
        BindingDemo_Harness()
            .previewDevice(.iPhone_8)
    }
}