ReSwift + Rx

RxStore.swift

import Foundation
import RxSwift

public class RxStore: StoreSubscriber {
    
    private var stateObservable:Observable<AppState> {
        return subject.asObserver()
            .shareReplay(1)
    }
    private var subject = PublishSubject<AppState>()
    private var store: Store<AppState>
    
    init(store: Store<AppState>) {
        self.store = store
        self.store.subscribe(self)
    }
    
    deinit {
        self.store.unsubscribe(self)
    }
    
    public func newState(newState: AppState) {
        subject.onNext(newState)
    }
    
    public func state<S:Equatable>(mapState:(AppState)->S) -> Observable<S>
    {
        return stateObservable
            .map(mapState)
            .distinctUntilChanged()
    }
    
}

var store = Store<AppState>(reducer: AppReducer(), state: nil, middleware: [rxMiddleware, loggingMiddleware])
var rxStore = RxStore(store: store)

rxStore.state { $0.userState }
  .subscribeNext { 
    print("user: \($0.user)")
  }
}