Swift playgrounds

published-struct.swift

//: A UIKit based Playground for presenting user interface
  
import Combine

struct ViewState {
    var a: Int
    var b: Int
}

class MyClass {
    @Published var viewstate = ViewState(a: 0, b: 0)
    
    var cancellables: Set<AnyCancellable> = []
    
    init() {
        $viewstate.sink { viewState in
            print(viewState)
        }.store(in: &cancellables)
        
        viewstate.a += 1
        viewstate.a += 1
    }
}

let myClass = MyClass()