Laimiux

interface CommentRepo {
  fun submitComment(comment: String): Observable<Lce<Comment>>
}

Laimiux

class CommentViewModel(val model: CommentFormModel) {
   fun viewStateStream(): Flowable<CommentFormViewState> { 
     // define the relays that will allow to complete unidirectional data flow
     val textChangedEventRelay = PublishRelay.create<TextChangedEvent>()
     val submitEventRelay = PublishRelay.create<SubmitCommentEvent>()
     
     return model
       .dataStream(
         // We pass the user action flowables to the CommentFormModel 
         textChangedEvents = textChangedEventRelay.toFlowable(Backpressure.LATEST),

Laimiux

class CommentFormPresenter(val viewModel: CommentViewModel) {
  fun attach(view: CommentFormView) {
    // Don't forget to unsubscribe
    viewModel.viewStateStream().subscribe { state ->
      view.setViewState(state)
    }
  }
}

Laimiux

class CommentFormView(val rootView: View) {
  // View binding logic
  val commentTextField: EditText = rootView.findViewById(R.id.comment_text_field)
  val submitButton: Button = rootView.findViewById(R.id.submit_button)
  
  // Our view update function, takes a view state
  // snapshot and updates the android views
  fun setViewState(state: CommentFormViewState) {
    commentTextField.text = state.textEntered
    submitButton.isEnabled = state.isSubmitButtonEnabled

Laimiux

data class CommentFormViewState(
  val textEntered: String,
  val isSubmitButtonEnabled: Boolean,
  val onTextEntered: (String) -> Unit, /* Callback when user modifies the text */
  val onSubmitButtonSelected: () -> Unit  /* Callback when user clicks submit button */)

Laimiux

fun reduce(event: TextChangedEvent, state: CommentFormData): CommentFormData {
  // Let's check comment validity
  val isValid = event.enteredText.length > 5
  // Update the current state with the changes
  return state.copy(comment = event.enteredText, isCommentValid = isValid)
}

Laimiux

class CommentFormModel(val commentService: CommentService) {
  
  fun formState(
    textChangedEvents: Observable<TextChangedEvent>,
    submitEvents: Observable<SubmitCommentEvent>
  ) : Observable<CommentFormData> {

    // Explicitly declaring the type, for clarity sake
    val requestStateEvents: Observable<Lce<Comment>> = submitEvents
      .switchMap { event -> commentService.submit(event.comment) }

Laimiux

fun createDataStream(
    textChangedEvents: Flowable<TextChangedEvent>,
    submitCommentEvents: Flowable<SubmitCommentEvent>
): Flowable<CommentFormData>

Laimiux

fun reduce(event: TextChangedEvent): (CommentFormData) -> CommentFormData {
  // implementation
  return { state -> 
    // Let's check comment validity
    val isValid = event.enteredText.length > 5
    // Update the current state with the changes
    return state.copy(comment = event.enteredText, isCommentValid = isValid)
  }
}

Laimiux

fun reduce(event: TextChangedEvent): Reducer<CommentFormData> {
  // implementation
}

fun reduce(event: Lce<Comment>): Reducer<CommentFormData> {
  // implementation  
}

 fun formState(