How to attach subscriber to State or Binding in SwiftUI/Combine?

Question

With a Combine Publisher, I can use the following to call a closure whenever a value changes:

let cancellable = x.sink { value in … }

How can I achieve the same behaviour with a variable marked @State or @Binding?

Answer 1

Update

The below answer doesn't seem to work anymore, instead one can use .onChange(of:) instead on the property

.onChange(of: someProperty) { value in
    //use new value for someProperty
 }

---

You can use willSet and didSet as with any normal property

@State private var someProperty: String {
    didSet {

    }

    willSet {

    }
}