rxdart 0.8.0

Native Dart rx implementation

RxDart

About

RxDart is a reactive functional programming library for Google Dart, based on ReactiveX.
Google Dart comes with a very decent Streams API out-of-the-box; rather than attempting to provide an alternative to this API, RxDart adds functionality on top of it.

How To Use RxDart

For Example: Reading the Konami Code

import 'package:rxdart/rxdart.dart';

void main() {

  // KONAMI CODE: UP, UP, DOWN, DOWN, LEFT, RIGHT, LEFT, RIGHT, B, A
  var codes = <int>[38, 38, 40, 40, 37, 39, 37, 39, 66, 65];
  var result = querySelector('#result');
  var controller = new StreamController<KeyboardEvent>();
  var stream = observable(controller.stream);

  document.addEventListener('keyup', (event) => controller.add(event));

  stream
    .map((event) => event.keyCode ) // Get the key code
    .bufferWithCount(10, 1) // Get the last 10 keys
    .where((list) => _areTwoListsEqual(list, codes)) // Check for matching values
    .listen((_) => result.innerHtml = 'KONAMI!');
}

bool _areTwoListsEqual(List<int> a, List<int> b) {
  for (int i=0; i<10; i++) if (a[i] != b[i]) return false;
  
  return true;
}

API Overview

RxDart's Observables extend the Stream class. This has two major implications:

• All methods defined on the Stream class exist on RxDart's Observables as well.
• All Observables can be passed to any API that expects a Dart Stream as an input.

Instantiation

Generally speaking, creating a new Observable is either done by wrapping a Dart Stream using the top-level method observable(), or by calling a factory method on the Observable class.
But to better support Dart's strong mode, combineLatest and zip have been pulled apart into fixed-length constructors. These methods are supplied as static methods, since Dart's factory methods don't support generic types.

Available Top-level Method

• observable

Usage

var myObservable = observable(myStream);

Available Factory Methods

• amb
• concat
• defer
• just
• merge
• periodic
• tween

Usage

var myObservable = new Observable.merge([myFirstStream, mySecondStream]);

Available Static Methods

• combineLatest (combineLatest2, combineLatest3, combineLatest4, ..., combineLatest9)
• zip (zip2, zip3, zip4, ..., zip9)

Usage

var myObservable = Observable.combineLatest3(
    myFirstStream, 
    mySecondStream, 
    myThirdStream, 
    (firstData, secondData, thirdData) => print(firstData + ' ' + secondData + ' ' + thirdData));

Transformations

Available Methods

• bufferWithCount
• call
• debounce
• flatMapLatest
• flatMap
• groupBy
• interval
• max
• min
• pluck
• repeat
• retry
• sample
• scan
• startWith
• startWithMany
• takeUntil
• timeInterval
• tap
• throttle
• windowWithCount
• withLatestFrom

Usage

var myObservable = observable(myStream)
    .bufferWithCount(5)
    .distinct()

Objects

• Observable
• BehaviourSubject
• ReplaySubject

Notable References

• Documentation on the Dart Stream class
• Tutorial on working with Streams in Dart
• ReactiveX (Rx)

Changelog

Refer to the Changelog to get all release notes.