Time traveling with ReSwift

Time traveling with ReSwift

@EliSawic

About me

Eliasz SawickiBlog: www.eliaszsawicki.comTwitter: @EliSawic

@EliSawic

ReSwift

@EliSawic

ReSwift is a Redux-like implementation of the unidirectional data flow

architecture in Swift.@EliSawic

Plan• How did it all start?

@EliSawic

Plan• How did it all start?

• How does it work?

@EliSawic

Plan• How did it all start?

• How does it work?

• What are my thoughts?

@EliSawic

How did it all start?

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What do we use?

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React

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Flux

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Redux

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Unidirectional Data Flow

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Unidirectional Data Flow• one direction of state change

• immutable state

• modified by pure functions

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DevTools

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Recording

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Time travel

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Fun to work with

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Dan Abramov

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ReSwift

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How does it work?

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Core Elements• State

• Actions

• Reducers

• Store

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State

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State

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Statestruct AppState: StateType, HasNavigationState { var user: User var navigationState: NavigationState}

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Actions

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Actionsstruct UpdateUserName: Action { let name: String

init(_ name: String) { self.name = name }}

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Action Creator

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Reducer

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Reducer(Action, State?) -> State

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

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Reducerfunc 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}

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Store

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Receives our letters

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Manage changes

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Notify about changes

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Storeprotocol Store { init(reducer: Reducer, state: State) func subscribe(subscriber: Subscriber) func dispatch(action: Action)}

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Event

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Send letter

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Receive letters

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Manage changes

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Notify about changes

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React to state changes

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What are my thoughts?

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DevTools

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Remember

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Keep reducers fast

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No side effects in Reducers

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Avoid heavy application state

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One way of changing state

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Why?

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Easy to understand what is going on

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Easy testing

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DevTools - Time traveling, Hot

reloading

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Fixing bugs with friends

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Why not?

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Overwhelming

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Boilerplate

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Many ReSwift components are in

POC state

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Easy to get stuck

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Against the framework

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Check them out!• Karl Bowden - @karlbowden

• Benjamin Encz - @benjaminencz

• Aleksander Rendtslev - @ARendtslev

• Dan Abramov - @danAbramov

@EliSawic

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

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Conclusion

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Thank you for your attention

@EliSawic