ca.swift_2.pdf

Transcript

1. RxSwift Operators Tips 2017/03/1 CA.swift
2. About Me ҏ౻ɹګฏ Github : KyoheiG3 Twitter : @KyoheiG3
5. ͖Ε͍ͳ઒ͷྲྀΕΛकΔͨΊͷ੍໿ͦͷᶃ ઒Λ෼அ͠ͳ͍
6. ͖Ε͍ͳ઒ͷྲྀΕΛकΔͨΊͷ੍໿ͦͷᶃ → DisposeBagΛෳ਺ʹ෼͚ͳ͍
7. flatMap
8. flatMap Observable͔Βૹ৴͞ΕͨΞΠςϜΛObservablesʹม׵͠ɺ ͦͷޙͦΕΒ͔Βૹ৴͞ΕΔΞΠςϜΛ̍ͭͷObservable΁ม ׵͢Δɻ
9. flatMap ઒͔Β઒΁ɺྲྀΕΛͭͳ͙
10. Bad Stream botton.rx.tap .subscribe(onNext: { URLSession.shared.rx.json(request: request) .subscribe(onNext: { ... }) .addDisposableTo(disposeBag) }) .addDisposableTo(disposeBag)
11. Good Stream botton.rx.tap .flatMap { URLSession.shared.rx.json(request: request) } .subscribe(onNext: { ... }) .addDisposableTo(disposeBag)
12. flatMapͷಛ௃ લճͷΠϕϯτ͕ऴ͍ྃͯ͠ͳͯ͘΋ΞΠςϜ͕ετϦʔϜʹྲྀ ΕΔͷͰɺಉ͡ॲཧ͕ෳ਺ճߦΘΕΔՄೳੑ͕͋Δɻ
13. ඇಉظॲཧͰ΍Γ͍ͨ͜ͱ ௨৴ͳͲͷඇಉظॲཧ͸ɺॲཧத͸ετϦʔϜΛྲྀ͞ͳ͍ɺ· ͨ͸࠷৽ͷετϦʔϜ͚ͩΛྲྀ͍ͨ͠ɻ
14. flatMapLatest
15. flatMapLatest ઒ͷྲྀΕΛஅͪ੾ͬͯɺ࣍ͷ઒΁ͱྲྀΕΛͭͳ͙
16. Bad Stream botton.rx.tap .subscribe(onNext: { requestDisposeBag = DisposeBag() URLSession.shared.rx.json(request: request) .subscribe(onNext: { ... }) .addDisposableTo(requestDisposeBag) }) .addDisposableTo(disposeBag)
17. Good Stream botton.rx.tap .flatMapLatest { URLSession.shared.rx.json(request: request) } .subscribe(onNext: { ... }) .addDisposableTo(disposeBag)
18. flatMapLatestͷಛ௃ ৽͍͠Πϕϯτ͕ىͬͨ͜ΒલͷΠϕϯτΛഁغͯ࣍͠ͷΠϕϯ τΛߦ͏ͷͰɺ୯Ұͷॲཧ͔͠ߦΘΕͳ͍ɻ Timer΍IntervalͳͲͷඇಉظॲཧ΋ɺflatMapLatestͱ૬ੑ͕ Α͍ɻ
19. Timer Stream botton.rx.tap .flatMapLatest { Observable<Int>.timer(1, scheduler: scheduler) } .subscribe(onNext: { ... }) .addDisposableTo(disposeBag)
20. debounceͱॲཧ͕Α͘ࣅ͍ͯΔ
21. Debounce botton.rx.tap .debounce(1, scheduler: scheduler) .subscribe(onNext: { ... }) .addDisposableTo(disposeBag)
22. DebounceͱTimer Streamͷҧ͍ ετϦʔϜʹྲྀΕ͖ͯͨ஋Λ΋ͱʹintervalΛม͑Δ͜ͱ͕Ͱ ͖Δɻ
23. έʔεͦͷᶃ ΞΠςϜΛड͚औ͔ͬͯΒɺҰఆ࣌ؒޙʹΞΠςϜΛετϦʔϜ ʹྲྀ͍ͨ͠ɻ஗Ԇ࣌ؒ͸ΞΠςϜͷ಺༰ʹΑͬͯ൑அ͢Δɻ
24. { "num": 10, "title": "Timer Stream" }
25. Timer Stream botton.rx.tap .flatMapLatest { URLSession.shared.rx.json(request: request) } .flatMapLatest { json -> Observable<Any?> in Observable<Int>.timer(json["num"] as! Int, scheduler: scheduler) .map { _ in json } } .subscribe(onNext: { ... }) .addDisposableTo(disposeBag)
26. έʔεͦͷᶄ ΞΠςϜΛड͚औͬͨΒετϦʔϜʹྲྀ͕͢ɺҰఆ࣌ؒޙʹnil ΛετϦʔϜʹྲྀ͍ͨ͠ɻ஗Ԇ࣌ؒ͸ΞΠςϜͷ಺༰ʹΑͬͯ ൑அ͢Δɻ
27. έʔεͦͷᶄ startWithΛ࢖͏
28. Timer Stream botton.rx.tap .flatMapLatest { URLSession.shared.rx.json(request: request) } .flatMapLatest { json -> Observable<Any?> in Observable<Int>.timer(json["num"] as! Int, scheduler: scheduler) .map { _ in nil } .startWith(json) } .subscribe(onNext: { ... }) .addDisposableTo(disposeBag)
29. flatMapFirst
30. flatMapFirst ઒ͷྲྀΕ͕ࢭ·Δ·Ͱɺ࣍ͷ઒΁͸ͭͳ͕ͳ͍
31. Bad Stream var requesting = false botton.rx.tap .subscribe(onNext: { if requesting { return } requesting = true requestDisposeBag = DisposeBag() URLSession.shared.rx.json(request: request) .subscribe(onNext: { requesting = false }) .addDisposableTo(requestDisposeBag) }) .addDisposableTo(disposeBag)
32. Good Stream botton.rx.tap .flatMapFirst { URLSession.shared.rx.json(request: request) } .subscribe(onNext: { ... }) .addDisposableTo(disposeBag)
33. flatMapFirstͷಛ௃ ࠷ॳʹૹ৴͞ΕͨΞΠςϜͷॲཧ͕׬ྃ͢Δ·Ͱ͸ɺͦͷޙʹ ૹΒΕͨΞΠςϜΛ఻ൖ͠ͳ͍ͷͰɺ୯Ұͷॲཧ͔͠ߦΘΕͳ ͍ɻ
34. Timer Stream botton.rx.tap .flatMapFirst { Observable<Int>.timer(1, scheduler: scheduler) } .subscribe(onNext: { ... }) .addDisposableTo(disposeBag)
35. throttleͱॲཧ͕Α͘ࣅ͍ͯΔ
36. Throttle botton.rx.tap .throttle(1, scheduler: scheduler) .subscribe(onNext: { ... }) .addDisposableTo(disposeBag)
37. Throttleͷ஫ҙ఺ throttle͸ετϦʔϜ1ൃ໨ͷΞΠςϜ͕ྲྀΕͯ͘ΔͬΆ͍ɻ ੲ͸ྲྀΕͯ͜ͳ͔ͬͨͷͰɺ΋͔ͨ͠͠ΒόʔδϣϯʹΑͬͯ มΘΔ͔΋ɻ
39. ͖Ε͍ͳ઒ͷྲྀΕΛकΔͨΊͷ੍໿ͦͷᶄ ઒ʹ΋ͷΛ౤͛ೖΕͳ͍
40. ͖Ε͍ͳ઒ͷྲྀΕΛकΔͨΊͷ੍໿ͦͷᶄ → ΫϩʔδϟͰselfΛࢀরͤ͞ͳ͍
41. selfΛࢀরͤ͞ͳ͍ํ๏ ෳ਺ͷετϦʔϜΛ߹੒ɺ͋Δ͍͸ঢ়ଶΛ஌Δඞཁ͕͋Δɻ RxͷoperatorsҰཡͳͲΛ֬ೝͯ͠Έͯɺ(x, y)Έ͍ͨʹ2ͭͷ ஋Λࢀর͍ͯ͠ΔΑ͏ͳoperator͸߹੒νϟϯεɻ ׬શʹࢀর͠ͳ͍ͷ͸೉͍͠ͷͰɺͰ͖ΔݶΓͰ΍ͬͯΈΔɻ
42. withLatestFrom
43. withLatestFrom ͋ΔετϦʔϜʹରͯ͠ɺผͷετϦʔϜͷ࠷৽ͷΞΠςϜΛ߹ ੒͢Δɻ
44. Bad Stream let other = Variable<Int>(0) botton.rx.tap .subscribe(onNext: { [weak self] in self?.other.asObservable() .subscribe(onNext: { ... }) .addDisposableTo(disposeBag) }) .addDisposableTo(disposeBag)
45. Self Reference let other = Variable<Int>(0) botton.rx.tap .subscribe(onNext: { [weak self] in print(self?.other.value) }) .addDisposableTo(disposeBag)
46. Good Stream let other = Variable<Int>(0) botton.rx.tap .withLatestFrom(other.asObservable()) .subscribe(onNext: { ... }) .addDisposableTo(disposeBag)
47. withLatestFromͷಛ௃ subscribeޙʹετϦʔϜʹྲྀΕͨ࠷৽ͷΞΠςϜͰ͋Ε͹ɺ VariableͷΑ͏ʹ஋Λอ͍࣋ͯ͠ͳͯ͘΋͍֮͑ͯͯ͘ΕΔͷ Ͱ߹੒͢Δ͜ͱ͕Ͱ͖Δɻ
48. Good Stream let other = PublishSubject<Int>() botton.rx.tap .withLatestFrom(other) .subscribe(onNext: { ... }) .addDisposableTo(disposeBag)
49. scan
50. scan Observable͔Βૹ৴͞ΕΔΞΠςϜʹ࿈ଓͯؔ͠਺Λద༻͢ Δɻ
51. Bad Stream let some = Variable<Int>(0) botton.rx.tap .flatMapLatest { URLSession.shared.rx.json(request: request) } .map { [weak self] json in let num = json["num"] as! Int if let value = self?.some.value { let new = value + num self?.some.value = new return new } return 0 } .subscribe(onNext: { ... }) .addDisposableTo(disposeBag)
52. Good Stream botton.rx.tap .flatMapLatest { URLSession.shared.rx.json(request: request) } .map { json in json["num"] as! Int } .scan(0) { some, new in some + new } .subscribe(onNext: { ... }) .addDisposableTo(disposeBag)
53. scanͷಛ௃ scanΛߦ͏͜ͱͰɺ͋ΔετϦʔϜʹରͯ͠ผͷΞΠςϜΛྲྀ ͢͜ͱ͕Ͱ͖Δɻ ετϦʔϜʹྲྀͨ͠ΞΠςϜ͸อ࣋͞Ε͍ͯΔͷͰɺ࣍ճετ ϦʔϜʹΞΠςϜ͕ྲྀΕ͖ͯͨࡍʹɺอ͍࣋ͯ͠ΔΞΠςϜͱ ྲྀΕ͖ͯͨΞΠςϜͷ྆ํΛಘΔ͜ͱ͕Մೳɻ
54. scanͷಛ௃ ৚݅ʹ߹Θͳ͚Ε͹ಉҰͷΞΠςϜΛྲྀ͠ଓ͚ͯɺ distinctUntilChangedΛ࣮ߦͯ͠ॲཧΛল͘͜ͱ΋Ͱ͖Δɻ
55. Good Stream botton.rx.tap .flatMapLatest { URLSession.shared.rx.json(request: request) } .map { json in json["num"] as! Int } .scan(0) { some, new in new > some ? new : some } .distinctUntilChanged() .subscribe(onNext: { ... }) .addDisposableTo(disposeBag)
56. scanͷಛ௃ อ͍࣋ͯ͠ΔΞΠςϜ͕มΘΔࡍʹɺݹ͍ΞΠςϜΛར༻ͯ͠ॲ ཧΛߦ͏Α͏ͳ͜ͱ΋Մೳɻ
57. Good Stream botton.rx.tap .flatMapLatest { URLSession.shared.rx.json(request: request) } .map { json in json["num"] as! Int } .scan(0) { some, new in if new > some { ... return new } return some } .distinctUntilChanged() .subscribe(onNext: { ... }) .addDisposableTo(disposeBag)
58. distinctUntilChanged
59. distinctUntilChanged ॏෳͨ͠ΞΠςϜͷ৔߹͸ૹ৴͠ͳ͍Α͏ʹ͢ΔΦϖϨʔλɻ
60. distinctUntilChanged botton.rx.tap .flatMapLatest { URLSession.shared.rx.json(request: request) } .map { json in json["num"] as! Int } .distinctUntilChanged() .subscribe(onNext: { ... }) .addDisposableTo(disposeBag)
61. distinctUntilChangedͷಛ௃ ΞΠςϜ͕EquatableͰ͸ͳ͍৔߹͸ΫϩʔδϟΛड͚औͬͯͦ ͷΫϩʔδϟΛ࣮ߦ͠ɺ໭Γ஋͕trueͷ͏ͪ͸ॲཧΛܧଓ͠ͳ ͍Α͏ͳৼΔ෣͍Λ͍ͯ͠Δɻ
62. distinctUntilChangedͷಛ௃ ετϦʔϜʹྲྀΕͨΞΠςϜΛอ͓͖࣋ͯ͠ɺ࣍ճετϦʔϜʹ ΞΠςϜ͕ྲྀΕ͖ͯͨࡍʹ৽چ྆ํͷΞΠςϜΛಘΔ͜ͱ͕Մ ೳɻ ॳظ஋Λؾʹ͠ͳ͍ͷͰ͋Ε͹ɺscanͱಉ͡Α͏ͳॲཧΛ΋͏ গ͠୹͘ॻ͘͜ͱ΋Ͱ͖Δɻ
63. distinctUntilChanged botton.rx.tap .flatMapLatest { URLSession.shared.rx.json(request: request) } .map { json in json["num"] as! Int } .distinctUntilChanged { old, new in if (new <= old) == false { ... } return new <= old } .subscribe(onNext: { ... }) .addDisposableTo(disposeBag)
64. ·ͱΊ
66. Thanks!