Medium article: SLC part 1 - ViewModel (simple)

AuthenticationViewModel.swift

// The cases should be named as if they were prefixed with the words
// "user intends to" or "user did"
enum AuthenticateNavigationStep {
    case signIn
    case signUp
}

final class AuthenticateViewModel: BaseViewModel<
    AuthenticateNavigationStep,
    AuthenticateViewModel.InputFromView,
    AuthenticateViewModel.Output
> {

    // MARK: - Overriding methods
    override func transform(input: Input) -> Output {
        func userIntends(to intention: AuthenticateNavigationStep) {
            navigator.navigate(to: intention)
        }

        [
            input.fromView.signUpTrigger
                .do(onNext: { userIntends(to: .signUp) })
                .drive(),

            input.fromView.signInTrigger
                .do(onNext: { userIntends(to: .signIn) })
                .drive()

        ].forEach { $0.disposed(by: bag) }

        return Output()
    }
}

extension AuthenticateViewModel {
    struct InputFromView {
        let signUpTrigger: Driver<Void>
        let signInTrigger: Driver<Void>
    }

    struct Output {}
}