setFrameAutosaveName.swift

import Cocoa

final class WindowController: NSWindowController {
    init() {
        let window = NSWindow()
        window.styleMask = [.closable, .miniaturizable, .resizable, .titled]
        super.init(window: window)
        
        self.shouldCascadeWindows = false
        window.setFrameAutosaveName(String(describing: type(of:self)))
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override var contentViewController: NSViewController? {
        didSet {
            self.window?.setFrameAutosaveName(String(describing: type(of:self)))
        }
    }

}

class ViewController: NSViewController {
    override func loadView() {
        self.view = NSView()
    }

    override func viewDidLoad() {
        super.viewDidLoad()
    }
}

let windowController = WindowController()
windowController.contentViewController = ViewController()
windowController.showWindow(nil)