SimpleReduxExampleViewController.swift

import Cocoa

class ViewController: NSViewController, StoreSubscriber {

    @IBOutlet weak var counterLabel: NSTextField!
    
    override func viewDidLoad() {
        super.viewDidLoad()

        store.subscribe(self)
    }

    @IBAction func userClickedPlus(_ sender: Any) {
        store.dispatch(action: IncreaseAction(increaseBy: 1))
    }
    
    @IBAction func userClickedMinus(_ sender: Any) {
        store.dispatch(action: DecreaseAction(decreaseBy: 1))
    }
    
    func newState(state: State) {
        counterLabel.stringValue = "\((state as? AppState)?.counter ?? 0)"
    }
}