Extending someone else's Swift enum to make it more friendly for a SwiftUI Picker

ContentView.swift

//
//  ContentView.swift
//  EnumExtensionPicker
//
//  Created by Chris Jones on 21/08/2020.
//

import SwiftUI

enum Strategy {
    case red
    case blue
    case none
}

class SomeThirdPartyThing {
    var strategy: Strategy

    init() {
        strategy = .none
    }
}

// The magic starts
extension Strategy: CaseIterable, Identifiable {
    var id: Strategy { self }

    var customString: String {
        switch self {
        case .none:
            return "None"
        case .red:
            return "Red"
        case .blue:
            return "Blue"
        }
    }
}
// The magic ends

var theClass = SomeThirdPartyThing()

struct ContentView: View {
    let strategyBinding: Binding<Strategy>

    init() {
        strategyBinding = Binding<Strategy>(
            get: { return theClass.strategy },
            set: {
                print("Setting new value to theClass: \($0.customString)")
                theClass.strategy = $0
            }
        )
    }

    var body: some View {
        Picker("Strategy", selection: strategyBinding) {
            ForEach(Strategy.allCases) { strategy in
                Text(strategy.customString).tag(strategy)
            }
        }
    }
}

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