1. Time traveling with
ReSwift
@EliSawic

2. About me
Eliasz Sawicki
Blog: www.eliaszsawicki.com
Twitter: @EliSawic
@EliSawic

3. ReSwift
@EliSawic

4. ReSwift is a Redux-like
implementation of the
unidirectional data flow
architecture in Swift.
@EliSawic

5. Plan
• How did it all start?
@EliSawic

6. Plan
• How did it all start?
• How does it work?
@EliSawic

7. Plan
• How did it all start?
• How does it work?
• What are my thoughts?
@EliSawic

8. How did it all start?
@EliSawic

9. What do we use?
@EliSawic

10. React
@EliSawic

11. Flux
@EliSawic

12. Redux
@EliSawic

13. Unidirectional Data
Flow
@EliSawic

14. Unidirectional Data Flow
• one direction of state change
• immutable state
• modified by pure functions
@EliSawic

15. DevTools
@EliSawic

16. Recording
@EliSawic

17. Time travel
@EliSawic

18. Fun to work with
@EliSawic

19. Dan Abramov
@EliSawic

20. ReSwift
@EliSawic

21. How does it work?
@EliSawic

22. Core Elements
• State
• Actions
• Reducers
• Store
@EliSawic

23. State
@EliSawic

24. State
@EliSawic

25. State
struct AppState: StateType, HasNavigationState {
var user: User
var navigationState: NavigationState
}
@EliSawic

26. Actions
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27. Actions
struct UpdateUserName: Action {
let name: String
init(_ name: String) {
self.name = name
}
}
@EliSawic

28. Action Creator
@EliSawic

29. Reducer
@EliSawic

30. Reducer
(Action, State?) -> State
@EliSawic

31. Update state
func handleAction(action: Action, state: AppState?) -> AppState {
return AppState(
user: userReducer(action, user: state?.user),
navState: navReducer(action, navState: state?.navState)
)
}
@EliSawic

32. Reducer
func userReducer(action: Action, user: User?) -> User {
var resultUser = user ?? User()
switch action {
case let action as UpdateUserName:
resultUser.name = action.name
case let action as UpdateUserSurname:
resultUser.surname = action.surname
case let action as UpdateUserPresentationTitle:
resultUser.presentationTitle = action.title
default:
break
}
return resultUser
}
@EliSawic

33. Store
@EliSawic

34. Receives our letters
@EliSawic

35. Manage changes
@EliSawic

36. Notify about changes
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37. Store
protocol Store {
init(reducer: Reducer, state: State)
func subscribe(subscriber: Subscriber)
func dispatch(action: Action)
}
@EliSawic

38. @EliSawic

39. Event
@EliSawic

40. Send letter
@EliSawic

41. Receive letters
@EliSawic

42. Manage changes
@EliSawic

43. Notify about changes
@EliSawic

44. React to state
changes
@EliSawic

45. What are my
thoughts?
@EliSawic

46. DevTools
@EliSawic

47. Remember
@EliSawic

48. Keep reducers fast
@EliSawic

49. No side effects in
Reducers
@EliSawic

50. Avoid heavy
application state
@EliSawic

51. One way of changing
state
@EliSawic

52. Why?
@EliSawic

53. Easy to understand
what is going on
@EliSawic

54. Easy testing
@EliSawic

55. DevTools - Time
traveling, Hot
reloading
@EliSawic

56. Fixing bugs with
friends
@EliSawic

57. Why not?
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58. Overwhelming
@EliSawic

59. Boilerplate
@EliSawic

60. Many ReSwift
components are in
POC state
@EliSawic

61. Easy to get stuck
@EliSawic

62. Against the
framework
@EliSawic

63. Check them out!
• Karl Bowden - @karlbowden
• Benjamin Encz - @benjaminencz
• Aleksander Rendtslev - @ARendtslev
• Dan Abramov - @danAbramov
@EliSawic

64. Check these out!
• https://karlbowden.com/reswift-prezzo/
• https://realm.io/news/benji-encz-unidirectional-data-flow-
swift/
• https://github.com/reactjs/redux
• https://github.com/ReSwift/ReSwift
@EliSawic

65. Conclusion
@EliSawic

66. Thank you for your
attention
@EliSawic