View, State, Action ... Unidirectional Data Flow is not a concept unique to React. Used for many years in Web development, it tends to propagate to mobile platforms. Why? Because it helps develop our UI and consider the changes as states and events.

This topic is not new on Android. But Kotlin and coroutines can now greatly improve our experience.

Let's see how we can structure our Android MVVM development with such an approach. Let's take some concrete samples and see how we can easily write it with just a Kotlin function, and even embrace functional programming.