Swidux

Swift unidirectional data flow inspired by redux.

Usage

Define your application state,

struct AppState {
    var count = 0
}

the list of actions that could be done,

enum CounterAction: Action {
    case increment
    case decrement
}

and how they impact the application state.

let counterReducer = Reducer<Int> { state, action in
    switch action {
    case CounterAction.increment: state += 1
    case CounterAction.decrement: state -= 1
    default: break
    }
}

Then initialize the application store,

let store = Store<AppState>(
    initialState: AppState(),
    reducer: counterReducer.lift(\.count)
)

subscribe any application state key path to be notified of state changes (make sure to keep reference to the token because its deallocation stop subscription).

let token = store.subscribe(\.count) { print($0) }

Now dispatch actions to mutate application state and use your subscription to state changes to update your UI, ...

store.dispatch(CounterAction.increment)
store.dispatch(CounterAction.decrement)

Discussions

AppState

Application state must be a value type because Swidux store rely on didSet observer to notify subscribers of state changes.

Reducers

Reducers use (inout State, Action) -> Void signature (instead of (State, Action) -> State) to improve performances and avoid lot of State copies.

Middleware

Middlewares allow to extend swidux architecture. They they are able to act before and after reducers and could be used to handle a wide variety of problems like logging, handling asynchronous actions, ...

Internaly, each middle get a dispatch function as parameter (plus the store to be able to get state) and return a wrapped one which will be used by the next middleware and finally by the swidux store.
Because of this you should take care of the order of the middlewares. A middleware could, for example, decide to don't propagate certain actions to the dispacth function (perhaps because these actions are only useful for its operation). If your middlewares contain a logger, these actions will be logged or not according to the order of the middlewares.

Installation

Carthage

Add the following dependency to your Cartfile:

github "clmntcrl/swidux" ~> 1.0

CocoaPods

Add the following pod to your Podfile:

pod 'Swidux', '~> 1.0'

SwiftPM

Add the package as dependency in your Package.swift:

dependencies: [
    .package(url: "https://github.com/clmntcrl/swidux.git", from: "1.0.0"),
]

License

Swidux is released under the MIT license. See LICENSE for details.