Add subfeature complete with dependency injection, more or less

Meow/Package.swift

@@ -11,48 +11,45 @@ let commonSwiftSettings: [SwiftSetting] = [
     .swiftLanguageMode(.v6)
 ]
 
+let tcaDependency = Target.Dependency.product(name: "ComposableArchitecture", package: "swift-composable-architecture")
+
 let package = Package(
     name: "Meow",
     platforms: [.iOS(.v18), .macOS(.v15)],
     products: [
-        // Products define the executables and libraries a package produces, making them visible to other packages.
-        .library(
-            name: "CatFactsKit",
-            targets: ["CatFactsKit"]
-        ),
-        .library(
-            name: "Root",
-            targets: ["Root"]
-        )
+        .library(name: "CatFactsKit", targets: ["CatFactsKit"]),
+        .library(name: "Core", targets: ["Core"]),
+        .library(name: "Root", targets: ["Root"]),
+        .library(name: "Facts", targets: ["Facts"])
     ],
     dependencies: [
         .package(url: "https://github.com/WeTransfer/Mocker", from: "3.0.2"),
         .package(url: "https://github.com/pointfreeco/swift-composable-architecture", from: "1.23.1"),
     ],
     targets: [
-        // Targets are the basic building blocks of a package, defining a module or a test suite.
-        // Targets can depend on other targets in this package and products from dependencies.
         .target(
             name: "CatFactsKit",
             swiftSettings: commonSwiftSettings
         ),
+        .target(
+            name: "Core",
+            dependencies: ["CatFactsKit", tcaDependency],
+            swiftSettings: commonSwiftSettings
+        ),
         .target(
             name: "Root",
-            dependencies: [
-                "CatFactsKit",
-                .product(name: "ComposableArchitecture", package: "swift-composable-architecture")
-            ],
+            dependencies: ["CatFactsKit", "Core", "Facts", tcaDependency],
+            swiftSettings: commonSwiftSettings
+        ),
+        .target(
+            name: "Facts",
+            dependencies: ["CatFactsKit", "Core", tcaDependency],
             swiftSettings: commonSwiftSettings
         ),
         .testTarget(
             name: "CatFactsKitTests",
-            dependencies: [
-                "CatFactsKit",
-                "Mocker"
-            ],
-            resources: [
-                .process("Fixtures")
-            ],
+            dependencies: ["CatFactsKit", "Mocker"],
+            resources: [.process("Fixtures")],
             swiftSettings: commonSwiftSettings
         ),
     ]

Meow/Sources/CatFactsKit/CatFacts.swift

@@ -5,8 +5,8 @@
 
 import Foundation
 
-public struct CatFacts {
-    let baseURL: URL
+public struct CatFacts: Sendable {
+    public let baseURL: URL
     let urlSession: URLSession
 
     public init(baseURL: URL, urlSession: URLSession = .shared) {

Meow/Sources/Core/CatFacts+Meow.swift

@@ -0,0 +1,25 @@
+//
+//  CatFacts+Meow.swift
+//  Core
+//
+
+import Foundation
+import CatFactsKit
+import ComposableArchitecture
+
+extension CatFacts: DependencyKey, TestDependencyKey {
+    public static var liveValue: CatFactsKit.CatFacts {
+        CatFacts(baseURL: URL(string: "https://barf.com")!)
+    }
+
+    public static var testValue: CatFactsKit.CatFacts {
+        CatFacts(baseURL: URL(string: "https://test.local")!)
+    }
+}
+
+public extension DependencyValues {
+    var catFacts: CatFacts {
+        get { self[CatFacts.self] }
+        set { self[CatFacts.self] = newValue }
+    }
+}

Meow/Sources/Core/ClientFactory.swift

@@ -0,0 +1,31 @@
+//
+//  ClientFactory.swift
+//  Meow
+//
+
+import Foundation
+import CatFactsKit
+import ComposableArchitecture
+
+public struct ClientFactory: Sendable {
+    public func createClient(baseURL: URL) -> CatFacts {
+        return CatFacts(baseURL: baseURL)
+    }
+}
+
+extension ClientFactory: DependencyKey, TestDependencyKey {
+    public static var liveValue: ClientFactory {
+        ClientFactory()
+    }
+
+    public static var testValue: ClientFactory {
+        ClientFactory()
+    }
+}
+
+public extension DependencyValues {
+    var clientFactory: ClientFactory {
+        get { self[ClientFactory.self] }
+        set { self[ClientFactory.self] = newValue }
+    }
+}

Meow/Sources/Facts/FactsFeature.swift

@@ -0,0 +1,64 @@
+//
+//  FactsFeature.swift
+//  Meow
+//
+
+import Foundation
+import Core
+import CatFactsKit
+import ComposableArchitecture
+
+@Reducer
+public struct FactsFeature {
+    @ObservationIgnored
+    @Dependency(\.clientFactory) var clientFactory
+
+    @ObservableState
+    public struct State {
+        public var baseURL: URL
+        public var mode: Mode = .notLoaded
+
+        public init(baseURL: URL = URL(string: "https://invalid.barf")!) {
+            self.baseURL = baseURL
+        }
+    }
+
+    public enum Mode {
+        case notLoaded
+        case loading
+        case loaded(facts: [String])
+        case error(Error)
+    }
+
+    public enum Action {
+        case viewAppeared
+        case receivedFacts([String])
+        case receivedError(Error)
+    }
+    
+    public init() { }
+
+    public var body: some ReducerOf<Self> {
+        Reduce { state, action in
+            switch action {
+            case .viewAppeared:
+                state.mode = .loading
+                let client = clientFactory.createClient(baseURL: state.baseURL)
+                return .run { send in
+                    do {
+                        let results = try await client.getFacts(count: 5)
+                        await send(.receivedFacts(results))
+                    } catch {
+                        await send(.receivedError(error))
+                    }
+                }
+            case let .receivedFacts(facts):
+                state.mode = .loaded(facts: facts)
+                return .none
+            case let .receivedError(error):
+                state.mode = .error(error)
+                return .none
+            }
+        }
+    }
+}

Meow/Sources/Facts/FactsView.swift

@@ -0,0 +1,42 @@
+//
+//  FactsView.swift
+//  Facts
+//
+
+import SwiftUI
+import Foundation
+import ComposableArchitecture
+
+public struct FactsView: View {
+    let store: StoreOf<FactsFeature>
+    
+    public init(store: StoreOf<FactsFeature>) {
+        self.store = store
+    }
+    
+    public var body: some View {
+        VStack {
+            switch store.state.mode {
+            case .notLoaded:
+                EmptyView()
+            case .loading:
+                ProgressView()
+            case let .loaded(facts):
+                List(facts, id: \.self) { fact in
+                    Text(fact)
+                }
+            case let .error(error):
+                Text(error.localizedDescription)
+            }
+        }
+        .onAppear {
+            store.send(.viewAppeared)
+        }
+    }
+}
+
+#Preview {
+    FactsView(store: .init(initialState: FactsFeature.State()) {
+        FactsFeature()
+    })
+}

Meow/Sources/Root/RootFeature.swift

@@ -4,24 +4,39 @@
 //
 
 import Foundation
+import Facts
+import CatFactsKit
 import ComposableArchitecture
 
 @Reducer
 public struct RootFeature {
     @ObservableState
     public struct State {
-        public var baseURL: String?
-        
+        var facts: FactsFeature.State = .init(baseURL: URL(string: "https://invalid.barf")!)
+        public var baseURL: URL?
+
         public init() { }
     }
-    
+
     public enum Action {
-        // Add your actions here
+        case viewAppeared
+        case facts(FactsFeature.Action)
     }
-    
+
     public init() { }
     
     public var body: some ReducerOf<Self> {
-        EmptyReducer()
+        Reduce { state, action in
+            switch action {
+            case .viewAppeared:
+                state.facts = .init(baseURL: URL(string: "https://meowfacts.herokuapp.com/")!)
+                return .none
+            case .facts:
+                return .none
+            }
+        }
+        Scope(state: \.facts, action: \.facts) {
+            FactsFeature()
+        }
     }
 }

Meow/Sources/Root/RootView.swift

@@ -4,23 +4,22 @@
 //
 
 import SwiftUI
+import Facts
 import ComposableArchitecture
 
 public struct RootView: View {
-    let store: StoreOf<RootFeature>
-    
+    @Bindable var store: StoreOf<RootFeature>
+
     public init(store: StoreOf<RootFeature>) {
         self.store = store
     }
     
     public var body: some View {
-        VStack {
-            Image(systemName: "globe")
-                .imageScale(.large)
-                .foregroundStyle(.tint)
-            Text("Hello, world!")
+        NavigationStack {
+            FactsView(store: store.scope(state: \.facts, action: \.facts))
+        }.onAppear {
+            store.send(.viewAppeared)
         }
-        .padding()
     }
 }