Hands-On Design Patterns with Swift

Using Observables with ViewModels

The Observable and Binding protocols help to reduce the boilerplate that's necessary when binding a particular view or control to the viewModel's properties.

Let's suppose that we have a simple form for registering users, with their name, password, and age. It can be represented with the following ViewModel:

class SignupViewModel {    var username = Observable<String?>(nil)    var email = Observable<String?>(nil)    var age = Observable<Double>(0.0)}extension SignupViewModel  {    var description: String {        return """username: \(username.value ?? "")email: \(email.value ?? "")age: \(age.value)"""    }}

With the ViewModel configured, we can take a look at SignupViewController. It is quite simple, with a few text fields and ...