TCAのようなアーキテクチャを作ってみた話

1. USZ
   4XJGU
   5PLZP
   4UVEFOU
   $MVC 5$"ͷΑ͏ͳΞʔΩςΫνϟΛ ࡞ͬͯΈͨ࿩ ΓΎ͏
   !SZV@IV
2. ࣗݾ঺հ w ΓΎ͏
   !SZV@IV
   
   w ๏੓େֶ
   ిؾిࢠ޻ֶՊ
   #
   w ൒೥͘Β͍4XJGU6* 5$"ͰษڧܥͷΞϓϦΛ։ൃͯ͠Δ
   ະϦϦʔε
   w $-*πʔϧ΍ϥΠϒϥϦΛ࡞Δͷ͕޷͖
3. w Ϟνϕʔγϣϯ
   w 5$"ʹ͍ͭͯ
   w ࣗ࡞ΞʔΩςΫνϟͷ֓ཁɾ࣮૷ʹ͍ͭͯ
   w ࣮ࡍʹΞϓϦΛ࡞੒͢Δ
   w ·ͱΊ
4. w Ϟνϕʔγϣϯ
   w 5$"ʹ͍ͭͯ
   w ࣗ࡞ΞʔΩςΫνϟͷ֓ཁɾ࣮૷ʹ͍ͭͯ
   w ࣮ࡍʹΞϓϦΛ࡞੒͢Δ
   w ·ͱΊ
5. Ϟνϕʔγϣϯ w 5$"ͷύϑΥʔϚϯε্ͷܽؕΛվળ͍ͨ͠
   w සൟʹ4UBUFΛมߋ͢Δ7JFXΛ࡞੒͍ͨ͠৔߹ɺ3FEVDFSΛհͯ͠4UBUFΛ มߋ͢ΔͱΧΫΧΫʹͳΔ
   w 5$"ʹͳ͔ͬͨཉ͍͠ػೳΛऔΓೖΕ͍ͨ
   w ΑΓγϯϓϧʹɺΘ͔Γ΍͍ͨ͘͢͠
   w ͳΜͱͳࣗ͘࡞ͰΞʔΩςΫνϟΛ࡞ͬͯΔਓʹಌΕ͕͋ͬͨ
6. w Ϟνϕʔγϣϯ
   w 5$"ʹ͍ͭͯ
   w ࣗ࡞ΞʔΩςΫνϟͷ֓ཁɾ࣮૷ʹ͍ͭͯ
   w ࣮ࡍʹΞϓϦΛ࡞੒͢Δ
   w ·ͱΊ
7. 5$"ʹ͍ͭͯ
8. 5$"ʹ͍ͭͯ w ΞϓϦέʔγϣϯͷঢ়ଶΛҰݩԽͯ͠4JOHMF
   4PVSDF
   PG
   5SVUIͷ࣮ݱΛͯ͠ ͍Δ
   w ਌ͷ4UBUF͔Βࢠͷ4UBUFʹΞΫηεՄೳ 4UBUF
9. 5$"ʹ͍ͭͯ 3FEVDFS w ਌ͷ3FEVDFS͸͢΂ͯͷࢠͷ3FEVDFSͷ"DUJPOΛड͚औΕΔ
10. 5$"ʹ͍ͭͯ ύϑΥʔϚϯε ͦͷੑ্࣭
    ֊૚͕Ұ൪Լͷ3FEVDFSͰ"DUJPO͕ݺ͹Εͨͱͯ͠΋ɺ਌͔Βࢠ·Ͱͷ
    ϧʔτʹ͋Δ͢΂ͯͷ3FEVDFS͕Α͹Εͯ͠·͏ɻ
    Αͬͯɺ֊૚͕ԼʹͳΔʹͭΕͯ"DUJPOΛૹ৴͢Δܭࢉίετ͕͔͔Δ "DUJPO͕ൃՐʂ
11. 5$"ʹ͍ͭͯ ϕϯνϚʔΫ ωετ͕ਂ͘ͳΕ͹ͳΔ΄Ͳɺ"DUJPOͷૹ৴଎౓͕஗͘ͳ͍ͬͯΔ͜ͱ͕Θ͔Δ
12. w Ϟνϕʔγϣϯ
    w 5$"ʹ͍ͭͯ
    w ࣗ࡞ΞʔΩςΫνϟͷ֓ཁɾ࣮૷ʹ͍ͭͯ
    w ࣮ࡍʹΞϓϦΛ࡞੒͢Δ
    w ·ͱΊ
13. ࣗ࡞ΞʔΩςΫνϟͷ֓ཁ w 3FEVDFSͷΠϯλʔϑΣʔε͸΄΅5$"
    w 5$"ͱҧͬͯࢠ͸਌3FEVDFSʹ݁߹͠ͳ͍
    w 7JFXͷঢ়ଶ؅ཧʹ!4UBUF΍!#JOEJOH
    !1VCMJTIFEͳͲ͕࢖͑Δ
    w ςελϒϧ
    w 3FEVDFS಺ͷΈʹ࢖༻Ͱ͖Δ3FEVDFS4UBUF΍3FEVDFS"DUJPOͳͲ͕͋Δ
14. 7JFX @ViewState struct CounterView: View { @State var counter = 0 let store: Store<CounterReducer> = Store(reducer: CounterReducer()) var body: some View { VStack { Text("\(counter)") Button("+") { send(.increment) } Button("-") { send(.decrement) } } } } ࣗ࡞ΞʔΩςΫνϟͷ֓ཁ !4UBUFΛ࢖༻ͯ͠ঢ়ଶΛఆٛ
15. 3FEVDFS ࣗ࡞ΞʔΩςΫνϟͷ֓ཁ @Reducer struct CounterReducer { enum ViewAction { case increment case decrement } func reduce( into state: StateContainer<CounterView>, action: Action ) -> SideEffect<Self> { switch action { case .increment: state.counter += 1 return .none case .decrement: state.counter -= 1 return .none } } } @ViewState struct CounterView: View { @State var counter = 0 ... } ઌ΄Ͳ7JFXͰఆٛͨ͠ঢ়ଶ͕3FEVDFS಺ͰมߋͰ͖Δ
16. 3FEVDFS4UBUF ࣗ࡞ΞʔΩςΫνϟͷ֓ཁ @Reducer struct CounterReducer { ... struct ReducerState { var totalCalledCount = 0 } func reduce( into state: StateContainer<CounterView>, action: Action ) -> SideEffect<Self> { state.reducerState.totalCalledCount += 1 ... } }
17. 3FEVDFS4UBUF ࣗ࡞ΞʔΩςΫνϟͷ֓ཁ w 5$"Ͱ͸7JFX4UBUFͱݺ͹ΕΔ֓೦͕͋Γɺෆඞཁͳ7JFXͷ࠶ϨϯμϦϯάΛ཈͑ͨ Γɺ7JFX༻ʹTUBUFΛՃ޻ͨ͠Γ͢Δ໨తͰ࢖༻͞ΕΔɻ
    w 3FEVDFS4UBUF΋ಉ͡Α͏ʹ
    ঢ়ଶΛมߋͯ͠΋7JFXͷ࠶ϨϯμϦϯά͸ى͜Βͳ͍
    w 7JFXͷΈͰ࢖༻͢Δ4UBUFͱɺ3FEVDFSͷΈͰ࢖༻͢Δ4UBUFͱͰ෼͚Δ͜ͱ͕Ͱ͖ɺ 7JFXଆͷՄಡੑͷ޲্ʹͭͳ͕Δ
18. 3FEVDFS"DUJPO ࣗ࡞ΞʔΩςΫνϟͷ֓ཁ @Reducer struct CounterReducer { enum ViewAction { case onAppear } enum ReducerAction { case response(TaskResult<Response>) } func reduce( into state: StateContainer<CounterView>, action: Action ) -> SideEffect<Self> { switch action { case .onAppear: return .run { send in await send( .response( TaskResult { try await request() } ) ) } case .response(let result): // ... do something } } } w 5$"Ͱ͸3FEVDFS಺ͷΈΞΫηεͰ͖Δ QSJWBUFͳ"DUJPO͸࡞Εͳ͔͕ͬͨɺຊΞʔ ΩςΫνϟͰ͸αϙʔτ
    w ྫ͑͹ɺ"1*͔Βͷ3FTQPOTFͳͲɺ7JFX͔ Β͸ݺͼͨ͘ͳ͍"DUJPOΛఆٛͰ͖Δ
    
19. 3FEVDFS"DUJPO ࣗ࡞ΞʔΩςΫνϟͷ֓ཁ @Reducer struct CounterReducer { enum ViewAction { case onAppear } enum ReducerAction { case response(TaskResult<Response>) } func reduce( into state: StateContainer<CounterView>, action: Action ) -> SideEffect<Self> { switch action { case .onAppear: return .run { send in await send( .response( TaskResult { try await request() } ) ) } case .response(let result): // ... do something } } } 3FEVDFS಺ʹ7JFX"DUJPOͱ3FEVDFS"DUJPO͠ ͔ఆ͍ٛͯ͠ͳ͍ͷʹɺ
    ͳ͔ͥ"DUJPO͕ར༻Ͱ͖Δɻ
    ͜ͷ"DUJPO͸ͳʹ͔ʁ
    
20. 3FEVDFS"DUJPO ࣗ࡞ΞʔΩςΫνϟͷ֓ཁ @Reducer struct CounterReducer { enum ViewAction { case onAppear } enum ReducerAction { case response(TaskResult<Response>) } func reduce( into state: StateContainer<CounterView>, action: Action ) -> SideEffect<Self> { switch action { case .onAppear: return .run { send in await send( .response( TaskResult { try await request() } ) ) } case .response(let result): // ... do something } } } 3FEVDFSϚΫϩʹΑͬͯɺ7JFX"DUJPOͱ 3FEVDFS"DUJPOΛ߹ମͨ͠"DUJPO͕ੜ੒͞ΕΔ
    enum Action: ActionProtocol { case onAppear case response(TaskResult<Response>) init(viewAction: ViewAction) { switch viewAction { case .onAppear: self = .onAppear } } init(reducerAction: ReducerAction) { switch reducerAction { case .response(let arg1): self = .response(arg1) } } }
21. 0CTFSWBCMF0CKFDU ࣗ࡞ΞʔΩςΫνϟͷ֓ཁ @ViewState final class MyModel: ObservableObject { @Published var count: Int = 0 let store: Store<MyReducer> = .init(reducer: MyReducer()) } w 0CTFSWBCMF0CKFDUͷ࢖༻΋ՄೳͰɺϩδοΫɾঢ়ଶΛڞ༗͍ͨ͠৔߹ ΍ɺ&OWJSPONFOU0CKFDUΛ࢖༻͍ͨ͠৔߹ͳͲʹ༗ޮ
    struct MyView: View { @ObservedObject private var model = MyModel() var body: some View { Button("+") { model.send(.increment) } } }
22. ςετ ࣗ࡞ΞʔΩςΫνϟͷ֓ཁ 5$"ͱ΄΅ಉ͡Α͏ʹςετ͕ॻ͚Δ
    func testSearchButtonTapped() async { let store = SearchView().testStore( viewState: SearchView.ViewState(), withDependencies: { $0.itemClient = ItemClient { _ in .stub } } ) await store.send(.onSearchButtonTapped) { $0.isLoading = true } await store.receive(.fetchItemsResponse(.success(.stub))) { $0.items = .stub $0.isLoading = false } }
23. ςετ ࣗ࡞ΞʔΩςΫνϟͷ֓ཁ ͔͠͠ɺ!4UBUF΍!#JOEJOH͸6OJU5FTUΛߦͳ͍ͬͯΔࡍɺ஋ΛೖΕͯ΋൓ө͞Εͳ͍
    ͲͷΑ͏ʹςελϒϧʹ͍ͯ͠Δͷ͔ʁ
24. ςετ ࣗ࡞ΞʔΩςΫνϟͷ࣮૷ ݁࿦ɺςετͷ࣌ͷΈ7JFXͷϓϩύςΟΛมߋ͢ΔͷͰ͸ͳ͘ɺ
    !7JFX4UBUFϚΫϩʹΑͬͯੜ੒͞Εͨߏ଄ମͷϓϩύςΟΛมߋ͍ͯ͠Δ func testSearchButtonTapped() async { let store = SearchView().testStore( viewState: SearchView.ViewState(), withDependencies: { $0.itemClient = ItemClient { _ in .stub } } ) await store.send(.onSearchButtonTapped) { $0.isLoading = true } await store.receive(.fetchItemsResponse(.success(.stub))) { $0.items = .stub $0.isLoading = false } }
25. ࣗ࡞ΞʔΩςΫνϟͷ࣮૷ @ViewState struct MyView: View { @State var count = 0 @State var isLoading = false var body: some View { EmptyView() } } 7JFX4UBUFϚΫϩΛల։͢Δͱ
26. ࣗ࡞ΞʔΩςΫνϟͷ࣮૷ @ViewState struct MyView: View { @State var count = 0 @State var isLoading = false var body: some View { EmptyView() } internal struct ViewState: ViewStateProtocol { var count = 0 var isLoading = false internal static let keyPathMap: [PartialKeyPath<ViewState>: PartialKeyPath<MyView>] = [ \.count: \.count, \.isLoading: \.isLoading ] } } extension MyView: ActionSendable { } 7JFX4UBUFߏ଄ମ͕ੜ੒͞Ε
    "DUJPO4FOEBCMFʹ४ڌ͞ΕΔ
27. ࣗ࡞ΞʔΩςΫνϟͷ࣮૷ @ViewState struct MyView: View { @State var count = 0 @State var isLoading = false var body: some View { EmptyView() } internal struct ViewState: ViewStateProtocol { var count = 0 var isLoading = false internal static let keyPathMap: [PartialKeyPath<ViewState>: PartialKeyPath<MyView>] = [ \.count: \.count, \.isLoading: \.isLoading ] } } extension MyView: ActionSendable { } !4UBUF͕෇༩͞ΕͨϓϩύςΟͷΈ7JFX4UBUFʹϓϩύςΟ͕ίϐʔ͞ΕΔ
28. ࣗ࡞ΞʔΩςΫνϟͷ࣮૷ 7JFX4UBUFͷ,FZ1BUI͔Β.Z7JFXͷ,FZ1BUI΁ͱม׵Ͱ͖ΔLFZ1BUI.BQΛఆٛ
    ޙ΄Ͳ࢖༻ @ViewState struct MyView: View { @State var count = 0 @State var isLoading = false var body: some View { EmptyView() } internal struct ViewState: ViewStateProtocol { var count = 0 var isLoading = false internal static let keyPathMap: [PartialKeyPath<ViewState>: PartialKeyPath<MyView>] = [ \.count: \.count, \.isLoading: \.isLoading ] } } extension MyView: ActionSendable { }
29. ࣗ࡞ΞʔΩςΫνϟͷ࣮૷ 7JFX4UBUFߏ଄ମʹ͸ͭͷॏཁͳ໾ׂ͕͋Δ  CPEZ΍TUPSFͳͲɺ7JFXͷঢ়ଶʹؔ܎ͷͳ͍ϓϩύςΟΛ4UBUF$POUBJOFSͰӅṭ͢Δ
    
    ςελϒϧʹ͢Δ func reduce( into state: StateContainer<CounterView>, action: Action ) -> SideEffect<Self> { switch action { case .increment: state.counter += 1 return .none } } TUBUF͔ΒɺCPEZ΍TUPSFʹ͸ΞΫηεͰ͖ͳ͍
30. ࣗ࡞ΞʔΩςΫνϟͷ࣮૷ public subscript<U>(dynamicMember keyPath: WritableKeyPath<Target.ViewState, U>) -> U { _read { #if DEBUG guard !isTesting else { yield viewState![keyPath: keyPath] return } #endif if let viewKeyPath = Target.ViewState.keyPathMap[keyPath] as? WritableKeyPath<Target, U> { yield target[keyPath: viewKeyPath] } else { fatalError() } } _modify { #if DEBUG guard !isTesting else { yield &viewState![keyPath: keyPath] return } #endif if let viewKeyPath = Target.ViewState.keyPathMap[keyPath] as? WritableKeyPath<Target, U> { yield &target[keyPath: viewKeyPath] } else { fatalError() } } } EZOBNJD.FNCFS-PPLVQͱ͸ɺΦϒδΣΫτʹଘࡏ͠ͳ͍ϓϩύςΟΛ
    ͔͋ͨ΋ଘࡏ͢ΔΑ͏ʹݟͤΔ͜ͱ͕Ͱ͖Δػೳ 4UBUF$POUBJOFS
31. ࣗ࡞ΞʔΩςΫνϟͷ࣮૷ public subscript<U>(dynamicMember keyPath: WritableKeyPath<Target.ViewState, U>) -> U { _read { #if DEBUG guard !isTesting else { yield viewState![keyPath: keyPath] return } #endif if let viewKeyPath = Target.ViewState.keyPathMap[keyPath] as? WritableKeyPath<Target, U> { yield target[keyPath: viewKeyPath] } else { fatalError() } } _modify { #if DEBUG guard !isTesting else { yield &viewState![keyPath: keyPath] return } #endif if let viewKeyPath = Target.ViewState.keyPathMap[keyPath] as? WritableKeyPath<Target, U> { yield &target[keyPath: viewKeyPath] } else { fatalError() } } } ද޲͖͸7JFX4UBUFͷϓϩύςΟΛ͍࣋ͬͯΔ͔ͷΑ͏ʹݟͤΔ͜ͱͰɺ
    3FEVDFS͔ΒCPEZ΍TUPSFͳͲͷϓϩύςΟʹΞΫηεͰ͖ͳ͍Α͏ʹ͍ͯ͠Δ 4UBUF$POUBJOFS
32. ࣗ࡞ΞʔΩςΫνϟͷ࣮૷ public subscript<U>(dynamicMember keyPath: WritableKeyPath<Target.ViewState, U>) -> U { _read { #if DEBUG guard !isTesting else { yield viewState![keyPath: keyPath] return } #endif if let viewKeyPath = Target.ViewState.keyPathMap[keyPath] as? WritableKeyPath<Target, U> { yield target[keyPath: viewKeyPath] } else { fatalError() } } _modify { #if DEBUG guard !isTesting else { yield &viewState![keyPath: keyPath] return } #endif if let viewKeyPath = Target.ViewState.keyPathMap[keyPath] as? WritableKeyPath<Target, U> { yield &target[keyPath: viewKeyPath] } else { fatalError() } } } ཪͰ͸ɺҾ਺Ͱड͚औͬͨ,FZ1BUIΛLFZ1BUI.BQΛ࢖༻ͯ͠7JFX4UBUF͔Β7JFXͷ ,FZ1BUI΁ͱม׵ͯ͠ 4UBUF$POUBJOFS
33. ࣗ࡞ΞʔΩςΫνϟͷ࣮૷ public subscript<U>(dynamicMember keyPath: WritableKeyPath<Target.ViewState, U>) -> U { _read { #if DEBUG guard !isTesting else { yield viewState![keyPath: keyPath] return } #endif if let viewKeyPath = Target.ViewState.keyPathMap[keyPath] as? WritableKeyPath<Target, U> { yield target[keyPath: viewKeyPath] } else { fatalError() } } _modify { #if DEBUG guard !isTesting else { yield &viewState![keyPath: keyPath] return } #endif if let viewKeyPath = Target.ViewState.keyPathMap[keyPath] as? WritableKeyPath<Target, U> { yield &target[keyPath: viewKeyPath] } else { fatalError() } } } 7JFXͷ஋ΛಡΈࠐΜͩΓॻ͖ࠐΜͩΓ͍ͯ͠Δɻ 4UBUF$POUBJOFS
34. ࣗ࡞ΞʔΩςΫνϟͷ࣮૷ public subscript<U>(dynamicMember keyPath: WritableKeyPath<Target.ViewState, U>) -> U { _read { #if DEBUG guard !isTesting else { yield viewState![keyPath: keyPath] return } #endif if let viewKeyPath = Target.ViewState.keyPathMap[keyPath] as? WritableKeyPath<Target, U> { yield target[keyPath: viewKeyPath] } else { fatalError() } } _modify { #if DEBUG guard !isTesting else { yield &viewState![keyPath: keyPath] return } #endif if let viewKeyPath = Target.ViewState.keyPathMap[keyPath] as? WritableKeyPath<Target, U> { yield &target[keyPath: viewKeyPath] } else { fatalError() } } } 4UBUF$POUBJOFS ςετ࣌͸7JFX΁ͷॻ͖ࠐΈͰ͸ͳ͘ɺ7JFX4UBUF΁ͷಡΈɾॻ͖ࠐΈʹ͢Δ͜ͱʹΑͬͯɺ
    ςελϒϧʹ͍ͯ͠Δ
35. w Ϟνϕʔγϣϯ
    w 5$"ʹ͍ͭͯ
    w ࣗ࡞ΞʔΩςΫνϟͷ֓ཁɾ࣮૷ʹ͍ͭͯ
    w ࣮ࡍʹΞϓϦΛ࡞੒͢Δ
    w ·ͱΊ
36. ࣮ࡍʹΞϓϦΛ࡞੒͢Δ ࣮ࡍʹ؆қతͳ(JUIVCͷϦϙδτϦݕࡧΞϓϦΛ࡞Δ
37. ࣮ࡍʹΞϓϦΛ࡞੒͢Δ @ViewState struct RootView: View { @State var searchText = "" @State var isLoading = false @State var repositories: [Repository] = [] @State var alertState: AlertState<Reducer.Action>? let store: Store<RootReducer> = Store(reducer: RootReducer()) var body: some View { NavigationStack { List { ForEach(repositories) { repository in NavigationLink(repository.fullName) { RepositoryView(repository: repository) .navigationTitle(repository.fullName) } } } .overlay { if isLoading { ProgressView() } } .searchable(text: $searchText) .onSubmit(of: .search) { send(.onSearchButtonTapped) } .onChange(of: searchText) { _, newValue in send(.onTextChanged(newValue)) } .alert(target: self, unwrapping: $alertState) } } 7JFX
38. ࣮ࡍʹΞϓϦΛ࡞੒͢Δ 3FEVDFS
    "DUJPO @Reducer struct RootReducer { enum ViewAction: Equatable { case onSearchButtonTapped case onTextChanged(String) } enum ReducerAction: Equatable { case fetchRepositoriesResponse(TaskResult<[Repository]>) case alert(Alert) enum Alert: Equatable { case retry } } ... }
39. ࣮ࡍʹΞϓϦΛ࡞੒͢Δ 3FEVDFS func reduce(into state: StateContainer<RootView>, action: Action) -> SideEffect<Self> { switch action { case .onSearchButtonTapped: state.isLoading = true return fetchRepositories(query: state.searchText) case .onTextChanged(let text): if text.isEmpty { state.repositories = [] } return .none case let .fetchRepositoriesResponse(.success(repositories)): state.isLoading = false state.repositories = repositories return .none case let .fetchRepositoriesResponse(.failure(error)): state.isLoading = false state.alertState = .init { TextState("An Error has occurred.") } actions: { ButtonState { TextState("OK") } ButtonState(action: .alert(.retry)) { TextState("Retry") } } message: { TextState(error.localizedDescription) } return .none case .alert(.retry): state.isLoading = true return fetchRepositories(query: state.searchText) }
40. ࣮ࡍʹΞϓϦΛ࡞੒͢Δ 3FEVDFS func reduce(into state: StateContainer<RootView>, action: Action) -> SideEffect<Self> { switch action { case .onSearchButtonTapped: state.isLoading = true return fetchRepositories(query: state.searchText) case .onTextChanged(let text): if text.isEmpty { state.repositories = [] } return .none case let .fetchRepositoriesResponse(.success(repositories)): state.isLoading = false state.repositories = repositories return .none case let .fetchRepositoriesResponse(.failure(error)): state.isLoading = false state.alertState = .init { TextState("An Error has occurred.") } actions: { ButtonState { TextState("OK") } ButtonState(action: .alert(.retry)) { TextState("Retry") } } message: { TextState(error.localizedDescription) } return .none case .alert(.retry): state.isLoading = true return fetchRepositories(query: state.searchText) } .onSubmit(of: .search) { send(.onSearchButtonTapped) } ݕࡧϘλϯ͕ԡ͞Εͨ࣌ɺϩʔυΛ։࢝͠ɺ
    ϦϙδτϦΛऔಘ͍ͯ͠Δ
41. ࣮ࡍʹΞϓϦΛ࡞੒͢Δ 3FEVDFS func reduce(into state: StateContainer<RootView>, action: Action) -> SideEffect<Self> { switch action { case .onSearchButtonTapped: state.isLoading = true return fetchRepositories(query: state.searchText) case .onTextChanged(let text): if text.isEmpty { state.repositories = [] } return .none case let .fetchRepositoriesResponse(.success(repositories)): state.isLoading = false state.repositories = repositories return .none case let .fetchRepositoriesResponse(.failure(error)): state.isLoading = false state.alertState = .init { TextState("An Error has occurred.") } actions: { ButtonState { TextState("OK") } ButtonState(action: .alert(.retry)) { TextState("Retry") } } message: { TextState(error.localizedDescription) } return .none case .alert(.retry): state.isLoading = true return fetchRepositories(query: state.searchText) } func fetchRepositories( query: String ) -> SideEffect<Self> { .run { send in await send( .fetchRepositoriesResponse( TaskResult { try await fetchRepositories(query) } ) ) } } ϦΫΤετΛૹ৴͠ɺ݁ՌΛ3FEVDFS"DUJPOͷ GFUDI3FQPTJUPSJFT3FTQPOTFΛૹ৴͍ͯ͠Δ
42. ࣮ࡍʹΞϓϦΛ࡞੒͢Δ 3FEVDFS func reduce(into state: StateContainer<RootView>, action: Action) -> SideEffect<Self> { switch action { case .onSearchButtonTapped: state.isLoading = true return fetchRepositories(query: state.searchText) case .onTextChanged(let text): if text.isEmpty { state.repositories = [] } return .none case let .fetchRepositoriesResponse(.success(repositories)): state.isLoading = false state.repositories = repositories return .none case let .fetchRepositoriesResponse(.failure(error)): state.isLoading = false state.alertState = .init { TextState("An Error has occurred.") } actions: { ButtonState { TextState("OK") } ButtonState(action: .alert(.retry)) { TextState("Retry") } } message: { TextState(error.localizedDescription) } return .none case .alert(.retry): state.isLoading = true return fetchRepositories(query: state.searchText) } ੒ޭͷ৔߹͸ϩʔσΟϯάΛதࢭ͠ɺ
    ݁ՌΛSFQPTJUPSJFTʹ୅ೖ͍ͯ͠Δ
43. ࣮ࡍʹΞϓϦΛ࡞੒͢Δ 3FEVDFS func reduce(into state: StateContainer<RootView>, action: Action) -> SideEffect<Self> { switch action { case .onSearchButtonTapped: state.isLoading = true return fetchRepositories(query: state.searchText) case .onTextChanged(let text): if text.isEmpty { state.repositories = [] } return .none case let .fetchRepositoriesResponse(.success(repositories)): state.isLoading = false state.repositories = repositories return .none case let .fetchRepositoriesResponse(.failure(error)): state.isLoading = false state.alertState = .init { TextState("An Error has occurred.") } actions: { ButtonState { TextState("OK") } ButtonState(action: .alert(.retry)) { TextState("Retry") } } message: { TextState(error.localizedDescription) } return .none case .alert(.retry): state.isLoading = true return fetchRepositories(query: state.searchText) } ࣦഊͷ৔߹΋ϩʔσΟϯάΛதࢭ͠ɺΞϥʔτΛग़ ͠ɺ3FUSZϘλϯΛ͓͢ͱɺ3FEVDFS"DUJPOͷ
    BMFSU SFUSZ ͕ݺ͹ΕΔ
44. ࣮ࡍʹΞϓϦΛ࡞੒͢Δ 3FEVDFS func reduce(into state: StateContainer<RootView>, action: Action) -> SideEffect<Self> { switch action { case .onSearchButtonTapped: state.isLoading = true return fetchRepositories(query: state.searchText) case .onTextChanged(let text): if text.isEmpty { state.repositories = [] } return .none case let .fetchRepositoriesResponse(.success(repositories)): state.isLoading = false state.repositories = repositories return .none case let .fetchRepositoriesResponse(.failure(error)): state.isLoading = false state.alertState = .init { TextState("An Error has occurred.") } actions: { ButtonState { TextState("OK") } ButtonState(action: .alert(.retry)) { TextState("Retry") } } message: { TextState(error.localizedDescription) } return .none case .alert(.retry): state.isLoading = true return fetchRepositories(query: state.searchText) } ϦτϥΠ͕ԡ͞ΕΔͱɺ࠶౓ϩʔσΟϯάΛ։࢝ ͠ɺϦϙδτϦͷऔಘͷϦΫΤετΛૹ৴͢Δ
45. ࣮ࡍʹΞϓϦΛ࡞੒͢Δ 3FEVDFS func reduce(into state: StateContainer<RootView>, action: Action) -> SideEffect<Self> { switch action { case .onSearchButtonTapped: state.isLoading = true return fetchRepositories(query: state.searchText) case .onTextChanged(let text): if text.isEmpty { state.repositories = [] } return .none case let .fetchRepositoriesResponse(.success(repositories)): state.isLoading = false state.repositories = repositories return .none case let .fetchRepositoriesResponse(.failure(error)): state.isLoading = false state.alertState = .init { TextState("An Error has occurred.") } actions: { ButtonState { TextState("OK") } ButtonState(action: .alert(.retry)) { TextState("Retry") } } message: { TextState(error.localizedDescription) } return .none case .alert(.retry): state.isLoading = true return fetchRepositories(query: state.searchText) } ςΩετͷೖྗΛPO$IBOHF PGJOJUJBM@ Ͱݕ஌͠ɺ
    7JFX"DUJPOPO5FYU$IBOHFEΛૹ৴͍ͯ͠Δ .onChange(of: searchText) { _, newValue in send(.onTextChanged(newValue)) } UFYU͕ۭʹͳͬͨ࣌ʹɺTUBUFSFQPTJUPSJFTΛۭʹ͍ͯ͠Δ
46. ࣮ࡍʹΞϓϦΛ࡞੒͢Δ 5FTU @MainActor final class RootReducerTests: XCTestCase { func testSearchButtonTapped() async { let store = RootView().testStore(viewState: RootView.ViewState()) { $0.repositoryClient = RepositoryClient( fetchRepositories: { _ in [.stub] } ) } await store.send(.onSearchButtonTapped) { $0.isLoading = true } await store.receive(.fetchRepositoriesResponse(.success([.stub]))) { $0.repositories = [.stub] $0.isLoading = false } } ... } ຊΞʔΩςΫνϟ͸TXJGUEFQFOEFODJFTʹ ରԠ͍ͯ͠ΔͷͰɺ
    ϞοΫ΁ͷࠩ͠ସ͕͑Մೳ
47. ࣮ࡍʹΞϓϦΛ࡞੒͢Δ 5FTU @MainActor final class RootReducerTests: XCTestCase { func testSearchButtonTapped() async { let store = RootView().testStore(viewState: RootView.ViewState()) { $0.repositoryClient = RepositoryClient( fetchRepositories: { _ in [.stub] } ) } await store.send(.onSearchButtonTapped) { $0.isLoading = true } await store.receive(.fetchRepositoriesResponse(.success([.stub]))) { $0.repositories = [.stub] $0.isLoading = false } } ... } Ϙλϯ͕ԡ͞Εͨ࣌ɺϦΫΤετ͕੒ޭͨ͠ ࣌ͷ஋ͷঢ়ଶͷมߋΛςετ
48. ࣮ࡍʹΞϓϦΛ࡞੒͢Δ 5FTU func testSearchButtonTappedInFailure() async { let error = CancellationError() let store = RootView().testStore(viewState: RootView.ViewState()) { $0.repositoryClient = RepositoryClient( fetchRepositories: { _ in throw error } ) } await store.send(.onSearchButtonTapped) { $0.isLoading = true } await store.receive(.fetchRepositoriesResponse(.failure(error))) { $0.isLoading = false $0.alertState = .init { TextState("An Error has occurred.") } actions: { ButtonState { TextState("OK") } ButtonState(action: .alert(.retry)) { TextState("Retry") } } message: { TextState(error.localizedDescription) } } } ࣍ʹϦΫΤετதʹΤϥʔΛൃੜͤͨ͞৔ ߹ͷςετΛ͢Δ
49. ࣮ࡍʹΞϓϦΛ࡞੒͢Δ 5FTU func testSearchButtonTappedInFailure() async { let error = CancellationError() let store = RootView().testStore(viewState: RootView.ViewState()) { $0.repositoryClient = RepositoryClient( fetchRepositories: { _ in throw error } ) } await store.send(.onSearchButtonTapped) { $0.isLoading = true } await store.receive(.fetchRepositoriesResponse(.failure(error))) { $0.isLoading = false $0.alertState = .init { TextState("An Error has occurred.") } actions: { ButtonState { TextState("OK") } ButtonState(action: .alert(.retry)) { TextState("Retry") } } message: { TextState(error.localizedDescription) } } } Τϥʔ͕ฦ͖ͬͯͨ৔߹ͷঢ়ଶͷมߋΛςετ
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