SwiftFlux

SwiftFlux is an implementation of Facebook's Flux architecure for Swift.
It provides concept of "one-way data flow" with type-safe modules by Swift language.

Type of an action's payload is inferred from the type of its action.
A result of an action is represented by Result, which is also known as Either.
Subscribe store to know state changed.

Requirements

Swift 2.2 or later
iOS 8.0 or later
Mac OS 10.9 or later
watch OS 2.0 or later

Installation

Carthage

Insert github "yonekawa/SwiftFlux" to your Cartfile.
Run carthage update.
Link your app with SwiftFlux.framework, Result.framework, in Carthage/Build

CocoaPods

Insert pod "SwiftFlux" to your Podfile:
Run pod install.

Usage

Step 1: Define Action

Assign type that represents a result object to Payload typealiase.
Define invoke to dispatching action to stores.
You can call api request here (you can use asynchronous request).

struct TodoAction {
    struct Create : Action {
        typealias Payload = Todo
        func invoke(dispatcher: Dispatcher) {
            let todo = Todo(title: "New ToDo")
            dispatcher.dispatch(self, result: Result(value: todo))
        }
    }
}

Step 2: Define Store and register action to dispatch

Register any subscribe action callback to dispatcher.
Unbox action result value by Either in callback.
Notify store's state change to subscribers by emitChange

class TodoStore : Store {
    private(set) var todos = [Todo]()

    init() {
        ActionCreator.dispatcher.register(TodoAction.List.self) { (result) in
            switch result {
            case .Success(let value):
                self.todos.append(value)
                self.emitChange()
            case .Failure(let error):
                NSLog("error \(error)")
                break;
            }
        }
    }
}

Step 3: Subscribe store at View

Subscribe store to know state changed.
Get result from store's public interface.

let todoStore = TodoStore()
todoStore.subscribe { () -> () in
    for todo in todoStore.todos {
        plintln(todo.title)
    }
}

Step 4: Create and invoke Action by ActionCreator

ActionCreator.invoke(TodoAction.Create())

Advanced

Destroy callbacks

Store registerer handler to Action by Dispatcher. Dispatcher has handler reference in collection. You need to release handler reference when store instance released.

class TodoStore {
    private var dispatchTokens: [DispatchToken] = []
    init() {
        dispatchTokens.append(
            ActionCreator.dispatcher.register(TodoAction.self) { (result) -> () in
              ...
            }
        )
    }

    func unregsiter() {
        for token in dispatchTokens {
            ActionCreator.dispatcher.unregister(token)
        }
    }
}

class TodoViewController {
  let store = TodoStore()
  deinit {
      store.unregister()
  }
}

StoreBase contains register/unregister utility. You can use these methods when override it to your own Store class.

Replace to your own Dispatcher

Override dispatcher getter of ActionCreator, you can replace app dispatcher.

class MyActionCreator: ActionCreator {
  static let ownDispatcher = YourOwnDispatcher()
  class MyActionCreator: ActionCreator {
    override class var dispatcher: Dispatcher {
        get {
            return ownDispatcher
        }
    }
}
class YourOwnDispatcher: Dispatcher {
    func dispatch<T: Action>(action: T, result: Result<T.Payload, T.Error>) {
        ...
    }
    func register<T: Action>(type: T.Type, handler: (Result<T.Payload, T.Error>) -> ()) -> String {
        ...
    }

    func unregister(dispatchToken: String) {
        ...
    }
    func waitFor<T: Action>(dispatchTokens: [String], type: T.Type, result: Result<T.Payload, T.Error>) {
        ...
    }
}

Use your own ErrorType instead of NSError

You can assign your own ErrorType with typealias on your Action.

struct TodoAction: ErrorType {
    enum TodoError {
        case CreateError
    }
    struct Create : Action {
        typealias Payload = Todo
        typealias Error = TodoError
        func invoke(dispatcher: Dispatcher) {
            let error = TodoError.CreateError
            dispatcher.dispatch(self, result: Result(error: error))
        }
    }
}

Flux Utils

SwiftFlux contains basic Store implementation utilities like as flux-utils.

StoreBase

StoreBase provides basic store implementation. For example, register/unregister callback of Action, etc.

class CalculateStore: StoreBase {
    private(set) var number = 0

    override init() {
        super.init()

        self.register(CalculateActions.Plus.self) { (result) in
            switch result {
            case .Success(let value):
                self.number += value
                self.emitChange()
            default:
                break
            }
        }

        self.register(CalculateActions.Minus.self) { (result) in
            switch result {
            case .Success(let value):
                self.number -= value
                self.emitChange()
            default:
                break
            }
        }
    }
}

ReduceStore

ReduceStore provides simply implementation to reduce the current state by reducer. Reducer receives the current state and Action's result. And reducer returns new state reduced. Reducer should be pure and have no side-effects. ReduceStore extends StoreBase.

class CalculateStore: ReduceStore<Int> {
    init() {
        super.init(initialState: 0)

        self.reduce(CalculateActions.Plus.self) { (state, result) -> Int in
            switch result {
            case .Success(let number): return state + number
            default: return state
            }
        }

        self.reduce(CalculateActions.Minus.self) { (state, result) -> Int in
            switch result {
            case .Success(let number): return state - number
            default: return state
            }
        }
    }
}

License

SwiftFlux is released under the MIT License.

yonekawa/SwiftFlux