Infinum iOS Talks #4 - Making our VIPER more reactive
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The document discusses Reactive VIPER and RxSwift. It introduces the VIPER architecture, which splits up the view controller into four main components: view, interactor, presenter, and wireframe. RxSwift is described as a library that uses functional reactive programming concepts to provide a declarative way to compose and transform observable sequences. Some key benefits of RxSwift mentioned are that it unifies various design patterns, enables building apps in a declarative reactive style, and treats observers and iterators as mathematical duals.
![CollectionType
- repeatable iteration
- access to the elements via index
struct BeersCollection<T> {
let beers: [T]
}](https://image.slidesharecdn.com/reactiveviper-161006121101/85/Infinum-iOS-Talks-4-Making-our-VIPER-more-reactive-26-320.jpg)
![CollectionType
extension BeersCollection: SequenceType {
typealias Generator = AnyGenerator<T>
func generate() -> AnyGenerator<T> {
var i = 0
return AnyGenerator {
i += 1
return i >= self.beers.count
?
nil
:
self.beers[i]
}
}
}](https://image.slidesharecdn.com/reactiveviper-161006121101/85/Infinum-iOS-Talks-4-Making-our-VIPER-more-reactive-27-320.jpg)
![USE [WEAK SELF]](https://image.slidesharecdn.com/reactiveviper-161006121101/85/Infinum-iOS-Talks-4-Making-our-VIPER-more-reactive-40-320.jpg)
Infinum iOS Talks #4 - Making our VIPER more reactive
- 2. WHY?
- 4. • workhorse • hard to test • hard to maintain • not reusable BUILDING BLOCK FOR COCOA TOUCH
- 5. VIPER
- 6. • in 4 parts • good for medium to big size applications • good separation of responsibility • loosely coupled components SPLIT UP VIEW CONTROLLER
- 7. • connection between components is achieved using protocols • composition instead inheritance in most cases • most of UI is done in Storyboards but without Segues GENERAL
- 8. • View / View Controller • Presenter (view model :)) • Interactor • Wireframe MAIN COMPONENTS
- 10. MAIN COMPONENTS
- 11. • business logic agnostic • knows how to layout itself • reusable VIEW / VIEW CONTROLLER
- 12. • business logic • least reusable part • has reference to • view • interactor • wireframe • models data received from interactor • views delegate (responds to view events) PRESENTER
- 13. • has the data • knows how to get the data INTERACTOR
- 14. • knows how to navigate • knows how to create other VIPER modules WIREFRAME
- 15. RX(SWIFT)
- 16. • FRP • functional programming • functions don’t have side effects, no mutable state • difficult to program since real world is all about side effects • reactive programming • changes propagate throughout a system automatically • functional reactive programming • we model user input as a function that changes over time, abstracting away the idea of mutable state CREATED BY MICROSOFT (RX.NET)
- 17. • sweet spot between functional and imperative programming world • unifies various design patterns (GoF) • Delegate • Callback (Closures, Blocks) • KVO • Notifications • Observer • enables building apps in declarative style WHY RX?
- 18. DECLARATIVE STYLE Observable .combineLatest ( firstName.rx_text, lastName.rx_text ) { $0 + " " + $1 } .map { "Greetings, ($0)" } .bindTo(greetingLabel.rx_text)
- 20. Observer and Iterator patterns are mathematical duals CORE KNOWLEDGE
- 21. ITERATOR PATTERN
- 22. • pull based interface • good for traversing collections • standard interface • generator • next (pull) • no more data • throw (error) • arrays, dictionaries, sets ITERATOR
- 23. • a collection of protocols • CollectionType • SequenceType • GeneratorType ITERATOR IN SWIFT
- 24. GeneratorType - serve elements protocol GeneratorType { associatedtype Element mutating func next() -> Element? }
- 25. SequenceType - knows how to create generator struct PrefixSequence: SequenceType { let string: String func generate() -> PrefixGenerator { return PrefixGenerator(string: string) } }
- 26. CollectionType - repeatable iteration - access to the elements via index struct BeersCollection<T> { let beers: [T] }
- 27. CollectionType extension BeersCollection: SequenceType { typealias Generator = AnyGenerator<T> func generate() -> AnyGenerator<T> { var i = 0 return AnyGenerator { i += 1 return i >= self.beers.count ? nil : self.beers[i] } } }
- 28. OBSERVER PATTERN
- 29. • push based interface • good for UI events • missing • error handling • no more data OBSERVER
- 30. Observer protocol PropertyObserver : class { func willChangePropertyName(propertyName: String, newPropertyValue: AnyObject?) func didChangePropertyName(propertyName: String, oldPropertyValue: AnyObject?) }
- 31. Observer class TestChambers { weak var observer: PropertyObserver? var testChamberNumber: Int = 0 { willSet(newValue) { observer?.willChangePropertyName("testChamberNumber", newPropertyValue:newValue) } didSet { observer?.didChangePropertyName("testChamberNumber", oldPropertyValue:oldValue) } } }
- 33. • unifying Iterator and Observer pattern • can be composed • we already know how to do operations on collections • map • filter • reduce • the equivalence of observer pattern (Observable<Element> sequence) and normal sequences (SequenceType) is the most important thing to understand about Rx GENERAL
- 34. • every observable sequence is just a sequence • push interface (aka callback) • regex • next* (error | completed)? • can have 0 or more elements • once error or completed • sequence cannot produce any other element • all internal resources will be disposed • no work will be performed until you call subscribe OBSERVABLES AKA SEQUENCES
- 35. TIPS’N’TRICKS
- 36. RTFM
- 38. ALWAYS USE `DISPOSE BAG`
- 40. USE [WEAK SELF]
- 42. STRIVE TO MODEL YOUR SYSTEMS AS PURE FUNCTIONS
- 43. RESOURCES
- 44. RESOURCES • RxSwift • Reactive Programming Overview • Design Patterns In Swift • Inside .Net Reactive Framework • Duality • Visual Operators (RxMarbles)
- 45. Q&A