Proxying properties from button style

ProxyButton.swift

//
//  ProxyButton.swift
//  Test
//
//  Created by Dmitry Gulyagin on 01/11/2024.
//

import SwiftUI

struct ProxyButtonState: Equatable {
    let isPressed: Bool
    let role: ButtonRole?
}

struct ProxyButton<Label>: View where Label: View {
    
    typealias Action = @MainActor () -> Void
    typealias LabelBuilder = (_ config: ProxyButtonState) -> Label
    
    private struct Style: ButtonStyle {
        let label: LabelBuilder
        func makeBody(configuration: Configuration) -> some View {
            label(ProxyButtonState(
                isPressed: configuration.isPressed,
                role: configuration.role
            ))
        }
    }
    
    private let action: Action
    private let label: LabelBuilder
    
    init(
        action: @escaping Action,
        @ViewBuilder label: @escaping LabelBuilder
    ) {
        self.action = action
        self.label = label
    }
    
    var body: some View {
        // Replace default label (1) to label (2) from style
        Button(
            action: action,
            label: EmptyView.init // 1
        ).buttonStyle(
            Style(label: label) // 2
        )
    }
    
}

#Preview {
    ProxyButton(
        action: { print("Tap") },
        label: { state in
            ZStack {
                Capsule()
                    .fill(state.isPressed ? .green : .blue)
                    .frame(width: 200, height: 50)
                Text(state.isPressed ? "Pressed" : "Not pressed")
                    .foregroundColor(.white)
                    .padding()
                    .id(state.isPressed)
                    .transition(
                        .move(edge: state.isPressed ? .top : .bottom)
                        .combined(with: .opacity)
                    )
            }
            .animation(.default, value: state.isPressed)
        }
    )
}