Getting Started with ReactiveCocoa v4.1.0

Reactive Swift Meetup (Apr 13, 2016)
http://wantedly.connpass.com/event/29039/

DemoApp: https://github.com/inamiy/ReactiveCocoaCatalog

Transcript

1. Getting Started with ReactiveCocoa v4.1.0 2016/04/13 Reactive Swift Meetup Yasuhiro Inami / @inamiy
2. Reactive Programming
4. Streams of Events over time
5. ReactiveCocoa (ObjC/Swift)
6. Signal (Hot Observable) SignalProducer (Cold Observable)
7. ‗ and ❄
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)
11. In short...
12. SignalProducer ↯ Signal ↯ Event
13. SignalProducer ↯ Signal ↓ Observer
14. SignalProducer ↯ Signal ↓ɹɹˣ ObserverɹObserver
15. SignalProducer ↯　　　　↯ SignalɹSignal ↓ɹɹɹɹˣ ObserverɹObserver
16. Function Composition
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!