SwiftUI Live Preview Logger

PreviewLogger.swift

#pragma mark - Article: https://sergey-nes.medium.com/enhance-your-swiftui-live-preview-workflow-with-previewlogger-6c768e7362a5

import SwiftUI

#pragma mark - ContentView

struct ContentView: View {
    @EnvironmentObject var previewLogger: PreviewLogger

    var body: some View {
        Button("Print Log") {
            previewLogger.log("Button tapped in SwiftUI preview!")
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
            .environmentObject(PreviewLogger.shared)
            .previewWrapper()
    }
}

#pragma mark - PreviewLogger

struct PreviewWrapper: ViewModifier {
    @EnvironmentObject var previewLogger: PreviewLogger

    func body(content: Content) -> some View {
        VStack {
            content
            List(previewLogger.logMessages.reversed(), id: \.self) { log in
                Text(log)
            }
        }
    }
}

extension View {
    func previewWrapper() -> some View {
        self.modifier(PreviewWrapper())
            .environmentObject(PreviewLogger.shared)
    }
}

class PreviewLogger: ObservableObject {
    static let shared = PreviewLogger()
    @Published private(set) var logMessages: [String] = []

    func log(_ message: String) {
        logMessages.append(message)
    }
}