Getting Started with ReactiveCocoa v4.1.0

Transcript

1. Getting Started with ReactiveCocoa v4.1.0 2016/04/13 Reactive Swift Meetup Yasuhiro

   Inami / @inamiy

2. Reactive Programming

3. None

4. Streams of Events over time

5. ReactiveCocoa (ObjC/Swift)

6. Signal (Hot Observable) SignalProducer (Cold Observable)

7. ‗ and ❄

8. None

9. Hot & Cold Observables • Hot Observable ‗ • always

   active (may lose data if not subscribed) • uses same underlying source (broadcasting) • Cold Observable ❄ • paused until subscription • clones underlying source (not broadcasting)
10. None

11. In short...

12. SignalProducer ↯ Signal ↯ Event

13. SignalProducer ↯ Signal ↓ Observer

14. SignalProducer ↯ Signal ↓ɹɹˣ ObserverɹObserver

15. SignalProducer ↯　　　　↯ SignalɹSignal ↓ɹɹɹɹˣ ObserverɹObserver

16. Function Composition

17. None

18. Signal -> Signal SignalProducer -> SignalProducer

19. Signal Operations • Transforming: map, mapError, scan, reduce, ... •

    Filtering: filter, take, takeUntil, skip, sampleOn, ... • Combining: flatten (Merge/Concat/Latest), combineLatest, zip, flatMap, flatMapError, ... • Timing: delay, throttle, timeoutWithError, ... • Utility: observeOn, materialize, dematerialize, ...

20. SignalProducer Operations • Transforming: map, mapError, scan, reduce, ... •

    Filtering: filter, take, takeUntil, skip, sampleOn, ... • Combining: flatten (Merge/Concat/Latest), combineLatest, zip, flatMap, flatMapError, ... • Timing: delay, throttle, timeoutWithError, ... • Utility: observeOn, materialize, dematerialize, ... • Producer-Only: startOn, concat, retry, etc...

21. Why do we need 2 different types?

22. Because ‗ and ❄ behaviors differ!

23. Define types based on its behavior (as simple as possible)

24. Signal / SignalProducer • Signal • Container for observers (for

    broadcasting) • .pipe = pair of (Signal, Observer) = Subject • SignalProducer • Container for startHandler (for cloning) • .buffer = pair of (SignalProducer, Observer) = ReplaySubject

25. Other data types • Observer: Wrapper of Event -> ()

    • Event: .Next, .Failed, .Completed, .Interrupted • Scheduler: GCD / NSThread wrapper • Disposable: Stateful container of () -> () • Property: Latest value + Signal(Producer) • Action: Stateful container of Input -> SignalProducer

26. Compared to other FRPs... • Protocol-oriented, no abstract classes &

    subclassing • Functional, much less types to learn • Separation of Signal & SignalProducer • No shareReplay, refCount (ConnectableObservable) • Typed errors • combineLatest(o1, o2, ...) ... no mixed error types • property <~ signal ... only NoError is allowed

27. Demo inamiy/ReactiveCocoaCatalog

28. Recap • ReactiveCocoa has separated hot & cold observables •

    Signal • SignalProducer • Type safe, including generic Error type • Use RAC if you like Result<T, E> more than Result<T> • RAC is beautiful !✨

29. Thanks!