simple combine example

simplecombine.swift

//
//  ViewController.swift
//  combinetest
//
//  Created by Michael on 2020-08-25.
//  Copyright © 2020 Michael. All rights reserved.
//

import Cocoa
import Combine

class ViewController: NSViewController {

    @Published public var slowdown: Bool = false {
        didSet {
            print("didset slowdown: \(oldValue)")
        }
    }
    private var cancellable: AnyCancellable?


    override func viewDidLoad() {
        super.viewDidLoad()

        slowdown = true
        slowdown = false
        slowdown = true
        slowdown = false
        cancellable = $slowdown.sink() { value in
            print("slowdown changed: \(value)")
        }

        print("after sink")
        slowdown = true
        slowdown = true
    }

    override var representedObject: Any? {
        didSet {
        // Update the view, if already loaded.
        }
    }
}

o/p:

didset slowdown: false
didset slowdown: true
didset slowdown: false
didset slowdown: true
slowdown changed: false
after sink
slowdown changed: true
didset slowdown: false
slowdown changed: true
didset slowdown: true
2020-08-25 12:52:22.157532-0400 combinetest[1991:35702] Metal API Validation Enabled