A super simple Cocoa App boilerplate for SwiftUI prototyping _without_ Xcode

SwiftUICocoaApp.swift

import Cocoa
import SwiftUI

func startApp(content: NSView) {
	let app			= NSApplication.shared
	let menubar 		= NSMenu()
	let appMenuItem  	= NSMenuItem()
	let appMenu 		= NSMenu()
	let appName 		= ProcessInfo.processInfo.processName
	let quitTitle    	= "Quit \(appName)"
	let quitMenuItem 	= NSMenuItem(title: quitTitle, action: #selector(NSApplication.terminate), keyEquivalent: "q")
	let windowRect	 	= NSRect(x: 0, y: 0, width: 480, height: 300)
	let styleMask: NSWindow.StyleMask = [.titled, .closable, .miniaturizable, .resizable, .fullSizeContentView]
	let window = NSWindow(contentRect: windowRect, styleMask: styleMask, backing: .buffered,  defer: false)
	
	app.setActivationPolicy(.regular)
	menubar.addItem(appMenuItem)
	app.mainMenu = menubar
	appMenu.addItem(quitMenuItem)
	appMenuItem.submenu = appMenu

	window.center()
	window.title = appName
	window.contentView = content
	window.makeKeyAndOrderFront(nil)
	app.run()
}

struct ContentView: View {
	var body: some View {
		Text("Hello")
		.font(.largeTitle)
		.frame(maxWidth: .infinity, maxHeight: .infinity)
	}
}

let content = NSHostingView(rootView: ContentView())

startApp(content: content)

How to run this?

> swift SwiftUICocoaApp.swift