Is there a better way to assign data using Combine - swiftui

Question

I am at the beginning phases of understanding Combine and to my surprise I actually got this simple model to work. In the model I simply pass data the .receive publisher in the init using .receive. What I'm wondering is:
Is there a better way to implement this functionality
None of it worked until I added .store() and passed in a Set = []. which to my understanding is a way to cancel the stream of data. But although it is just to cancel to stream, the stream also will not work without it. Wondering if my understanding of that is correct and if there is a better to way to implement the cancellable.
import SwiftUI
import Combine
struct ContentView: View {
#ObservedObject var viewModel = SimpleViewModel()
#State private var changer = ""
var body: some View {
VStack {
TextField("ENTER TEXT TO PASS", text: $changer)
.padding()
.textFieldStyle(RoundedBorderTextFieldStyle())
HStack(alignment: .top) {
Button(action: {
viewModel.changer = self.changer
}){
Text("Change")
.fontWeight(.bold)
.padding()
.foregroundColor(.white)
.background(Color.blue)
.cornerRadius(10)
}
VStack {
Button(action: {}){
Text("Receive")
.fontWeight(.bold)
.padding()
.foregroundColor(.white)
.background(Color.green)
.cornerRadius(10)
}
Group {
Text(viewModel.firstValue).bold()
Text(viewModel.secondValue).bold()
Text(viewModel.thirdValue).bold()
}.padding(.vertical)
}
}
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
final class SimpleViewModel: ObservableObject {
#Published var changer = ""
#Published var firstValue = "Value #1"
#Published var secondValue = "Value #2"
#Published var thirdValue = "Value #3"
private var cancellableSet: Set<AnyCancellable> = []
init() {
$changer
.receive(on: RunLoop.main)
.assign(to: \.firstValue, on: self)
.store(in: &cancellableSet)
}
}

Answer 1

I assume in this case you can use just didSet, like
final class SimpleViewModel: ObservableObject {
#Published var changer = "" {
didSet { firstValue = changer }
}
// ... other code
}