Subscribe to substate? about bansa HOT 1 CLOSED

class CurrentUserSubscriber(val store: Store<AppState>) {
    fun subscribe(subscriber: (User?) -> Unit): Subscription {
        val subscription = store.subscribe {
            // Use this part of the function to narrow down to the part of the state you care about
            subscriber(it.userState.currentUser)
        }

        return Subscription { subscription.unsubscribe() };
    }
}

@Test
    fun `store should be able to subscribe to substate`() {
        val reducer = Reducer<AppState> { state, action ->
            when (action) {
                is User -> state.copy(userState = state.userState.copy(currentUser = action))
                else -> state
            }
        }
        val store = BaseStore(AppState(), reducer);
        var currentUser: User? = null

        // Create an instance of our Substate-Subscriber     
        val currentUserSubscriber = CurrentUserSubscriber(store)

        // Subscribe to the substate using our class
        currentUserSubscriber.subscribe { currentUser = it }

        val user = User("Brian")

        // Dispatch a new User to the store
        store.dispatch(user)

        // Shows that our substate subscriber worked!
        assertThat(currentUser).isEqualTo(user)
    }