SwiftUI focus-losing/first responder-losing (blur) text field

swiftui-blur-textfield.swift

import SwiftUI

@main
struct ExampleApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

struct ClickableBackground: NSViewRepresentable {
    typealias ClickableCallback = (ClickableNSView) -> Void;
    
    let onClick: ClickableCallback;
    
    init(_ callback: @escaping ClickableCallback) {
        self.onClick = callback;
    }
    
    class ClickableNSView: NSView {
        var onClick: ClickableCallback = { _ in };
        
        override func mouseDown(with event: NSEvent) {
            self.onClick(self);
        }
    }
    
    func makeNSView(context: Context) -> ClickableNSView {
        let view = ClickableNSView();
        view.onClick = self.onClick;
        
        return view;
    }
    
    func updateNSView(_ nsView: ClickableNSView, context: Context) { }
}

struct ContentView: View {
    @State var input: String = "";
    
    var body: some View {
        VStack(content: {
            TextField("Sample Input", text: self.$input)
        })
        .padding()
        .frame(maxWidth: .infinity, maxHeight: .infinity)
        .background(ClickableBackground({ nsView in
            nsView.window?.makeFirstResponder(nil);
        }))
        .onAppear(perform: {
            DispatchQueue.main.async(execute: {
                NSApplication.shared.keyWindow?.makeFirstResponder(nil);
            })
        })
    }
}