Allow to notify on changes only

Sources/CombineRex/BindableStore.swift

@@ -65,7 +65,6 @@ extension BindableStore where ViewState: Equatable {
         self.init(initialState: initialState,
                   viewStore: viewStore,
                   removeDuplicates: { $0.removeDuplicates() })
-
     }
 }
 

Sources/SwiftRex/CoreTypes/Pipeline/Middleware.swift

@@ -171,23 +171,6 @@ public protocol Middleware: class {
     func handle(action: InputActionType, next: @escaping Next)
 }
 
-extension Middleware {
-    /**
-     Handles the incoming actions and may or not start async tasks, check the latest state at any point or dispatch
-     additional actions. This is also a good place for analytics, tracking, logging and telemetry.
-     - Parameters:
-       - action: the action to be handled
-       - next: opportunity to call the next middleware in the chain and, eventually, the reducer pipeline. Call it
-               only once, not more or less than once. Call it from the same thread and runloop where the handle function
-               is executed, never from a completion handler or dispatch queue block. In case you don't need to compare
-               state before and after it's changed from the reducers, please consider to add a `defer` block with `next()`
-               on it, at the beginning of `handle` function.
-     */
-    public func handle(action: InputActionType, next: @escaping Next) {
-        next()
-    }
-}
-
 // sourcery: AutoMockable
 // sourcery: AutoMockableGeneric = StateType
 // sourcery: AutoMockableGeneric = OutputActionType

Sources/SwiftRex/CoreTypes/StoreImplementations/ReduxPipelineWrapper.swift

@@ -9,13 +9,20 @@ public struct ReduxPipelineWrapper<MiddlewareType: Middleware>: ActionHandler
 
     public init(state: UnfailableReplayLastSubjectType<StateType>,
                 reducer: Reducer<ActionType, StateType>,
-                middleware: MiddlewareType) {
+                middleware: MiddlewareType,
+                emitsChange: @escaping (StateType, StateType) -> Bool) {
         self.middleware = middleware
 
         let reduce: (ActionType) -> Void = { action in
-            state.mutate { value in
-                value = reducer.reduce(action, value)
-            }
+            state.mutate(
+                when: { $0 },
+                action: { value -> Bool in
+                    let newValue = reducer.reduce(action, value)
+                    guard emitsChange(value, newValue) else { return false }
+                    value = newValue
+                    return true
+                }
+            )
         }
 
         let middlewarePipeline: (ActionType) -> Void = { [unowned middleware] action in
@@ -42,3 +49,11 @@ public struct ReduxPipelineWrapper<MiddlewareType: Middleware>: ActionHandler
         onAction(action)
     }
 }
+
+extension ReduxPipelineWrapper where StateType: Equatable {
+    public init(state: UnfailableReplayLastSubjectType<StateType>,
+                reducer: Reducer<ActionType, StateType>,
+                middleware: MiddlewareType) {
+        self.init(state: state, reducer: reducer, middleware: middleware, emitsChange: !=)
+    }
+}

Sources/SwiftRex/CoreTypes/StoreImplementations/ReduxStoreBase.swift

@@ -74,9 +74,30 @@ open class ReduxStoreBase<ActionType, StateType>: ReduxStoreProtocol {
      */
     public init<M: Middleware>(subject: UnfailableReplayLastSubjectType<StateType>,
                                reducer: Reducer<ActionType, StateType>,
-                               middleware: M)
+                               middleware: M,
+                               emitsChange: ShouldEmitChange<StateType> = .always)
         where M.InputActionType == ActionType, M.InputActionType == M.OutputActionType, M.StateType == StateType {
         self.subject = subject
-        self.pipeline = .init(state: subject, reducer: reducer, middleware: AnyMiddleware(middleware))
+            self.pipeline = .init(state: subject, reducer: reducer, middleware: AnyMiddleware(middleware), emitsChange: emitsChange.evaluate)
     }
 }
+
+public struct ShouldEmitChange<StateType> {
+    fileprivate let evaluate: (StateType, StateType) -> Bool
+
+    private init(evaluate: @escaping (StateType, StateType) -> Bool) {
+        self.evaluate = evaluate
+    }
+}
+
+extension ShouldEmitChange {
+    public static var always: ShouldEmitChange<StateType> { .init(evaluate: { _, _ in true }) }
+    public static var never: ShouldEmitChange<StateType> { .init(evaluate: { _, _ in false }) }
+    public static var when: (@escaping (StateType, StateType) -> Bool) -> ShouldEmitChange<StateType> {
+        ShouldEmitChange<StateType>.init
+    }
+}
+
+extension ShouldEmitChange where StateType: Equatable {
+    public static var whenChange: ShouldEmitChange<StateType> { .init(evaluate: !=) }
+}

Sources/SwiftRex/Foundation/ReactiveWrappers.swift

@@ -98,6 +98,15 @@ extension ReplayLastSubjectType {
         subscriber.onValue(currentValue)
         return result
     }
+
+    @discardableResult
+    public func mutate<Result>(when condition: @escaping (Result) -> Bool, action: (inout Element) -> Result) -> Result {
+        var currentValue = value()
+        let result = action(&currentValue)
+        guard condition(result) else { return result }
+        subscriber.onValue(currentValue)
+        return result
+    }
 }
 
 public typealias UnfailableReplayLastSubjectType<Element> = ReplayLastSubjectType<Element, Never>

Sources/SwiftRex/Middlewares/IdentityMiddleware.swift

@@ -19,4 +19,20 @@ public final class IdentityMiddleware<InputActionType, OutputActionType, GlobalS
             fatalError("No context set for middleware PipelineMiddleware, please be sure to configure your middleware prior to usage")
         }
     }
+
+    /**
+     Handles the incoming actions and may or not start async tasks, check the latest state at any point or dispatch
+     additional actions. This is also a good place for analytics, tracking, logging and telemetry.
+     In this empty implementation, will do nothing but call next delegate.
+     - Parameters:
+       - action: the action to be handled
+       - next: opportunity to call the next middleware in the chain and, eventually, the reducer pipeline. Call it
+               only once, not more or less than once. Call it from the same thread and runloop where the handle function
+               is executed, never from a completion handler or dispatch queue block. In case you don't need to compare
+               state before and after it's changed from the reducers, please consider to add a `defer` block with `next()`
+               on it, at the beginning of `handle` function.
+     */
+    public func handle(action: InputActionType, next: @escaping Next) {
+        next()
+    }
 }

SwiftRex.xcodeproj/project.pbxproj

@@ -183,6 +183,7 @@
 		D598492E22C023CD00F99D09 /* ReplayLastSubjectType+BehaviorSubject.swift in Sources */ = {isa = PBXBuildFile; fileRef = D51A223422BFF1EA00194408 /* ReplayLastSubjectType+BehaviorSubject.swift */; };
 		D598492F22C023CE00F99D09 /* ReplayLastSubjectType+BehaviorSubject.swift in Sources */ = {isa = PBXBuildFile; fileRef = D51A223422BFF1EA00194408 /* ReplayLastSubjectType+BehaviorSubject.swift */; };
 		D598493022C023CF00F99D09 /* ReplayLastSubjectType+BehaviorSubject.swift in Sources */ = {isa = PBXBuildFile; fileRef = D51A223422BFF1EA00194408 /* ReplayLastSubjectType+BehaviorSubject.swift */; };
+		D59DDF7F235CC8980056A10E /* IntegrationCounterTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D59DDF7E235CC8980056A10E /* IntegrationCounterTests.swift */; };
 		D5A022B022BED5C600797438 /* SubscriberTypeBridgeTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D5A022AF22BED5C600797438 /* SubscriberTypeBridgeTests.swift */; };
 		D5A022BA22BED8B000797438 /* TypeErase.generated.abstract.swift in Sources */ = {isa = PBXBuildFile; fileRef = D55EFB0C207EBAA300BC8822 /* TypeErase.generated.abstract.swift */; };
 		D5A022BB22BED8B000797438 /* TypeErase.generated.swift in Sources */ = {isa = PBXBuildFile; fileRef = D59D57EB207AA1B40010412E /* TypeErase.generated.swift */; };
@@ -526,6 +527,7 @@
 		D59D5807207AA1B40010412E /* StateProvider.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = StateProvider.swift; sourceTree = "<group>"; };
 		D59D5809207AA1B40010412E /* StoreType.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = StoreType.swift; sourceTree = "<group>"; };
 		D59D580A207AA1B40010412E /* ReduxStoreBase.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ReduxStoreBase.swift; sourceTree = "<group>"; };
+		D59DDF7E235CC8980056A10E /* IntegrationCounterTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = IntegrationCounterTests.swift; sourceTree = "<group>"; };
 		D5A022AF22BED5C600797438 /* SubscriberTypeBridgeTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = SubscriberTypeBridgeTests.swift; sourceTree = "<group>"; };
 		D5A2EAE922B9A00E00CA10B8 /* ReactiveSwiftRex.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = ReactiveSwiftRex.h; sourceTree = "<group>"; };
 		D5A2EAEE22B9A05600CA10B8 /* RxSwiftRex.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = RxSwiftRex.h; sourceTree = "<group>"; };
@@ -888,6 +890,7 @@
 			children = (
 				D5326483233E30F800CF0589 /* IssueTrackerTests39.swift */,
 				D56E317D235A746C00BEF634 /* IntegrationWithComposableMiddlewareTests.swift */,
+				D59DDF7E235CC8980056A10E /* IntegrationCounterTests.swift */,
 			);
 			path = Integration;
 			sourceTree = "<group>";
@@ -2965,6 +2968,7 @@
 				D5FEA881234D7DCF003486A7 /* BlockPublisher.swift in Sources */,
 				D5FEA883234D7EBC003486A7 /* SubscriberTypeBridgeTests.swift in Sources */,
 				D56E317C235A5D7600BEF634 /* IssueTrackerTests39.swift in Sources */,
+				D59DDF7F235CC8980056A10E /* IntegrationCounterTests.swift in Sources */,
 				D5FEA885234D7F1D003486A7 /* ReplayLastSubjectTypeBridgeTests.swift in Sources */,
 				D56E317E235A746C00BEF634 /* IntegrationWithComposableMiddlewareTests.swift in Sources */,
 			);

SwiftRex.xcworkspace/xcshareddata/xcschemes/Playgrounds.xcscheme

@@ -14,9 +14,9 @@
             buildForAnalyzing = "YES">
             <BuildableReference
                BuildableIdentifier = "primary"
-               BlueprintIdentifier = "D532CA05223EC2C900AB13EF"
-               BuildableName = "RxSwiftRex.framework"
-               BlueprintName = "SwiftRex iOS RxSwift"
+               BlueprintIdentifier = "D5C1C5F722BFE6AA00532BCF"
+               BuildableName = "CombineRex.framework"
+               BlueprintName = "SwiftRex iOS Combine"
                ReferencedContainer = "container:SwiftRex.xcodeproj">
             </BuildableReference>
          </BuildActionEntry>
@@ -40,15 +40,6 @@
       debugDocumentVersioning = "YES"
       debugServiceExtension = "internal"
       allowLocationSimulation = "YES">
-      <MacroExpansion>
-         <BuildableReference
-            BuildableIdentifier = "primary"
-            BlueprintIdentifier = "D532CA05223EC2C900AB13EF"
-            BuildableName = "RxSwiftRex.framework"
-            BlueprintName = "SwiftRex iOS RxSwift"
-            ReferencedContainer = "container:SwiftRex.xcodeproj">
-         </BuildableReference>
-      </MacroExpansion>
    </LaunchAction>
    <ProfileAction
       buildConfiguration = "Release"
@@ -59,9 +50,9 @@
       <MacroExpansion>
          <BuildableReference
             BuildableIdentifier = "primary"
-            BlueprintIdentifier = "D532CA05223EC2C900AB13EF"
-            BuildableName = "RxSwiftRex.framework"
-            BlueprintName = "SwiftRex iOS RxSwift"
+            BlueprintIdentifier = "D5C1C5F722BFE6AA00532BCF"
+            BuildableName = "CombineRex.framework"
+            BlueprintName = "SwiftRex iOS Combine"
             ReferencedContainer = "container:SwiftRex.xcodeproj">
          </BuildableReference>
       </MacroExpansion>

SwiftRexPlaygrounds.playground/Pages/Simple Counter.xcplaygroundpage/Contents.swift

@@ -3,53 +3,113 @@
 // Please start by selecting target Playgrounds and any iPhone from the device list
 // Then build the target and run the playground
 
+import Combine
+import CombineRex
 import PlaygroundSupport
 import SwiftRex
 
 PlaygroundPage.current.needsIndefiniteExecution = true
 
-// App state, shared among all modules of our app
-struct GlobalState: Equatable, Codable {
-    var currentNumber = 0
+enum AppAction: Equatable {
+    case event(CounterEvent)
+    case action(CounterAction)
+
+    enum CounterEvent: Equatable {
+        case requestIncrease, requestDecrease
+    }
+
+    enum CounterAction: Equatable {
+        case increase, decrease
+    }
+
+    public var event: CounterEvent? {
+        get {
+            guard case let .event(value) = self else { return nil }
+            return value
+        }
+        set {
+            guard case .event = self, let newValue = newValue else { return }
+            self = .event(newValue)
+        }
+    }
+
+    public var action: CounterAction? {
+        get {
+            guard case let .action(value) = self else { return nil }
+            return value
+        }
+        set {
+            guard case .action = self, let newValue = newValue else { return }
+            self = .action(newValue)
+        }
+    }
 }
 
-// For simplicity, this enum is both an Event and an Action
-// DirectLineMiddleware transfers it directly to the reducers
-enum CounterEvent: EventProtocol, ActionProtocol, Equatable {
-    case increase, decrease
+struct AppState: Codable, Equatable {
+    var currentNumber = 0
 }
 
-// Only one Action type to handle, no need for sub-reducers
-let reducer = Reducer<GlobalState> { state, action in
-    guard let counterEvent = action as? CounterEvent else { return state }
+enum CounterService {
+    static let middleware = CounterMiddleware()
 
-    var state = state
-    switch counterEvent {
-    case .increase: state.currentNumber += 1
-    case .decrease: state.currentNumber -= 1
+    static let reducer = Reducer<AppAction.CounterAction, Int> { action, state in
+        switch action {
+        case .increase: return state + 1
+        case .decrease: return state - 1
+        }
     }
 
-    return state
+    class CounterMiddleware: Middleware {
+        typealias InputActionType = AppAction.CounterEvent
+        typealias OutputActionType = AppAction.CounterAction
+        typealias StateType = Int
+
+        var context: () -> MiddlewareContext<AppAction.CounterAction, Int> = { fatalError("Not set yet") }
+
+        func handle(action: AppAction.CounterEvent, next: @escaping Next) {
+            next()
+            switch action {
+            case .requestIncrease: context().dispatch(.increase)
+            case .requestDecrease: context().dispatch(.decrease)
+            }
+        }
+    }
 }
 
-// Store glues all pieces together
-final class Store: StoreBase<GlobalState> {
+final class Store: ReduxStoreBase<AppAction, AppState> {
     init() {
-        super.init(initialState: GlobalState(), reducer: reducer, middleware: DirectLineMiddleware())
+        super.init(
+            subject: .combine(initialValue: AppState()),
+            reducer:
+                CounterService.reducer.lift(
+                    action: \AppAction.action,
+                    state: \AppState.currentNumber
+                ),
+            middleware:
+                CounterService.middleware.lift(
+                    actionZoomIn: { $0.event },
+                    actionZoomOut: {
+                        return AppAction.action($0)
+                    },
+                    stateZoomIn: { $0.currentNumber }
+                ),
+            emitsChange: .whenChange
+        )
     }
 }
 
 let store = Store()
-store
+let subscription = store
+    .statePublisher
     .map { String(data: try! JSONEncoder().encode($0), encoding: .utf8)! }
-    .subscribe(onNext: { print("New state: \($0)") })
-
-store.dispatch(CounterEvent.increase)
-store.dispatch(CounterEvent.increase)
-store.dispatch(CounterEvent.increase)
-store.dispatch(CounterEvent.decrease)
-store.dispatch(CounterEvent.increase)
-store.dispatch(CounterEvent.decrease)
-store.dispatch(CounterEvent.decrease)
+    .sink { print("New state: \($0)") }
+
+store.dispatch(.event(.requestIncrease))
+store.dispatch(.event(.requestIncrease))
+store.dispatch(.event(.requestIncrease))
+store.dispatch(.event(.requestDecrease))
+store.dispatch(.event(.requestIncrease))
+store.dispatch(.event(.requestDecrease))
+store.dispatch(.event(.requestDecrease))
 
 //: [Next](@next)

SwiftRexPlaygrounds.playground/contents.xcplayground

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
-<playground version='6.0' target-platform='ios' display-mode='rendered' executeOnSourceChanges='false'>
+<playground version='6.0' target-platform='ios' display-mode='rendered'>
     <pages>
         <page name='Simple Counter'/>
         <page name='Mock Async Counter'/>

SwiftRexPlaygrounds.playground/playground.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IDEDidComputeMac32BitWarning</key>
+	<true/>
+</dict>
+</plist>