Functional Reactive Programming

Functional Reactive Programming

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  MY AFFAIR REACTIVECOCOA with FUNCTIONAL REACTIVE PROGRAMMING
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  FUNCTIONAL REACTIVE PROGRAMMING
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  // Imperative programming varx = 1, y = 2, z = y + x; console.log(z); //3 x = 2; console.log(z); //3 // Reactive programming var x = 1, y = 2, z = y + x; console.log(z); //3 x = 2; console.log(z); //4
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  FUNCTIONAL PROGRAMMING REACTIVE
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  FUNCTIONAL PROGRAMMING DECLARATIVE EVALUATIONOF PURE FUNCTIONS TO CREATE IMMUTABLE PROGRAMS AND SO AVOID SIDE EFFECTS THAT ARE EXTERNALLY OBSERVED.
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  PURE FUNCTIONS DECLARATIVE PROGRAMMING REFERENTIALTRANSPARENCY INMUTABILITY // Imperative programming var arrayFoo = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]; for (var i = 0; i < arrayFoo.length; i++) { arrayFoo[i] = Math.pow(arrayFoo[i], 2); } array; // [0, 1, 4, 9, 16, 25, 36, 49, 64, 81] // Declarative programming [0, 1, 2, 3, 4, 5, 6, 7, 8, 9].map(num => Math.pow(num, 2)); // [0, 1, 4, 9, 16, 25, 36, 49, 64, 81]
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  PURE FUNCTIONS DECLARATIVE PROGRAMMING REFERENTIALTRANSPARENCY INMUTABILITY // Impure function var likes = 0; function addLike() { return ++likes; } // Pure function function addLike(likes) { return ++likes; } addLike(addLike(0)); // 2
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  DECLARATIVE PROGRAMMING REFERENTIAL TRANSPARENCY INMUTABILITY PUREFUNCTIONS // Referential transparent function int plusOne(int x) { return x+1; } // Referential opaqueness function int G = 10; int plusG(int x) {//G can be modified externally returning different values. return x + G; }
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  DECLARATIVE PROGRAMMING REFERENTIAL TRANSPARENCY INMUTABILITY PUREFUNCTIONS // Referential transparent function int plusOne(int x) { return x+1; } // Referential opaqueness function int G = 10; int plusG(int x) {//G can be modified externally returning different values. return x + G; }
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  REACTIVE PROGRAMMING FUNCTIONAL
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  : https://goo.gl/NaMmJ : https://goo.gl/sGSwMS Reactiveprogramming is programming with asynchronous data streams.
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  A stream isa sequence of ongoing events ordered in time.
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  HANDS ON!
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  // RxSwift LoginViewModel structLoginViewModel { let usernameBGColor: Driver<UIColor> let passwordBGColor: Driver<UIColor> let credentialsValid: Driver<Bool> init(usernameText: Driver<String>, passwordText: Driver<String>) { let usernameValid = usernameText .distinctUntilChanged() .throttle(0.3) .map { $0.utf8.count > 3 } let passwordValid = passwordText .distinctUntilChanged() .throttle(0.3) .map { $0.utf8.count > 3 } usernameBGColor = usernameValid .map { $0 ? BG_COLOR : UIColor.white } passwordBGColor = passwordValid .map { $0 ? BG_COLOR : UIColor.white } credentialsValid = Driver.combineLatest(usernameValid, passwordValid) { $0 && $1 } } func login(_ username: String, password: String) -> Observable<AutenticationStatus> { return AuthManager.sharedManager.login(username, password: password) }