Get The PID Of The App Currently Focused On macOS With Swift

import SwiftUI

struct ContentView: View {
    
    func focusedAppPid() -> Optional<pid_t> {
        if let process = NSWorkspace.shared.frontmostApplication {
            return process.processIdentifier
        } else {
            return Optional.none
        }
    }
    
    var body: some View {
        if let pid = focusedAppPid() {
            Text(String(pid))
                .padding()
        } else {
            Text("could not get pid")
                .padding()
        }
    }
}

#Preview {
    ContentView()
}