Kotlin Redux

Redux.kt

class Store<S, A>(initialState: S, private val reducer: (S, A) -> S) {
    private val TAG = "Redux"

    private val stateProcessor: BehaviorProcessor<S> = BehaviorProcessor.create()
    private val eventProcessor: PublishProcessor<Event<S, A>> = PublishProcessor.create()

    init {
        stateProcessor.onNext(initialState)
    }

    fun stateObs(): Observable<S> {
        return stateProcessor.toObservable()
    }

    fun subscribeTo(actionsObs: Observable<A>): Disposable {
        return actionsObs.subscribe(this::applyAction, Timber.tag(TAG)::e)
    }

    fun applyAction(action: A) {
        val newState = reducer(stateProcessor.value, action)
        stateProcessor.onNext(newState)
        eventProcessor.onNext(Event(newState, action))
    }

    fun eventObs(): Observable<Event<S, A>> {
        return eventProcessor.toObservable()
    }

    data class Event<S, A>(val state: S, val action: A)
}