Why unidirectional architecture matter for iOS.

In this talk, I am trying to discover what factors make the unidirectional architectures more efficient for day to day development.

Screencast(Russian language): https://vimeo.com/224279675

1. UNIDIRECTIONAL WHY IT IS IMPORTANT?
2. DEBUGGING IS TWICE AS HARD AS WRITING A PROGRAM IN THE FIRST PLACE. Brian Kernighan "The Elements of Programming Style" (1980)
3. WHY?
4. CODE HAPPINESS
5. CODE EVOLUTION
6. IMPLICIT IMPACT
7. OK, SO?
8. COST
9. TIME
10. QUALITY
11. SO?
12. WHY SUFFER?
13. THIS IS SOFTWARE
14. WE CAN DO BETTER
15. IMPOSSIBLE STATES https://www.youtube.com/watch?list=PLglJM3BYAMPH2zuz1nbKHQyeawE4SN0Cd&v=IcgmSRJHu_8
16. struct Quiz { let questions: [String] let answers: [String?] }
17. struct Quiz { struct Question { let text: String let answer: String? } let questions: [Question] }
18. struct Quiz { struct Question { let text: String let answer: String? } let questions: [Question] let current: Question }
19. struct Quiz { struct Question { let text: String let answer: String? } let previousQuestions: [Question] let current: Question let nextQuestions: [Question] }
20. INTENT / ACTION SEPARATION
21. class APIClient { func requestQuiz() -> Future<Quiz> } let apiClient = APIClient() // or DI var quiz: Quiz? func refreshQuiz() { apiClient.requestQuiz().onComplete { quiz = $0 } }
22. enum Effects { case requestQuiz((Quiz) -> Void) } func refreshQuiz() -> Effects { return Effects.requestQuiz { quiz = $0 } }
23. func perform(effect: Effects) { switch effect { case .requestQuiz(let callback): apiClient.requestQuiz() .onComplete(action: callback) } }
24. enum Effects { case requestQuiz((Quiz) -> Effects) case updateQuiz(Quiz) } func refreshQuiz() -> Effects { return Effects.requestQuiz(Effects.updateQuiz) }
25. func perform(effect: Effects) { switch effect { case .requestQuiz(let callback): apiClient.requestQuiz().onComplete { perform(effect: callback($0)) } case .updateQuiz(let newQuiz): quiz = newQuiz } }
26. ☝ELM https://guide.elm-lang.org
27. TOOLING
28. https://github.com/zalmoxisus/remotedev
29. print(effect)
30. CQRS https://martinfowler.com/bliki/CommandQuerySeparation.html
32. LIMITED SCOPE
33. REACT https://facebook.github.io/react/docs/thinking-in-react.html
34. STATE / DATA SEPARATION
35. struct Quiz { struct Question { let text: String let answer: String? } let previousQuestions: [Question] let current: Question let nextQuestions: [Question] }
36. class ViewController: UIViewController { var quiz: Quiz? }
37. class ViewController: UIViewController { struct Props { let questions: [( text: String, isAnswered: Bool )] } }
38. extension ViewController.Props { init(quiz: Quiz) { let allQuestions = quiz.previousQuestions + [quiz.current] + quiz.nextQuestions self.questions = allQuestions.map { ($0.text, $0.answer != nil) } } }
39. REDUX https://egghead.io/courses/building-react-applications-with-idiomatic-redux
40. EFFECT ACTION STATE PROPS
42. QUESTIONS? DALOG@ME.COM