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Questions tagged [rx-swift]

RxSwift's intention is to enable easy composition of asynchronous operations and event/data streams. Use this tag only for questions that are specific to the RxSwift - Reactive Programming paradigm, or those that require code in the language. Use the related tags [ios], [osx], [apple-watch], [cocoa-touch], and [cocoa] for (language-agnostic) questions about the platforms or frameworks.

About Rx and RxSwift

Rx is a generic abstraction of computation expressed through Observable<Element> interface.

RxSwift is a Swift version of Rx.

It tries to port as many concepts from the original version as possible, but some concepts were adapted for more pleasant and performant integration with iOS/macOS environment.

Cross platform documentation can be found on ReactiveX.io.

Like the original Rx, its intention is to enable easy composition of asynchronous operations and event/data streams.

KVO observing, async operations and streams are all unified under abstraction of sequence. This is the reason why Rx is so simple, elegant and powerful.

Resources

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RxSwift -- MainScheduler.instance vs MainScheduler.asyncInstance

What is the difference between using RxSwift's MainSchedule.instance and MainSchedule.asyncInstance within the context of observeOn?
udi80z
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How to bind rx_tap (UIButton) to ViewModel?

I have authorization controller with 2 UITextField properties and 1 UIButton. I want to bind my View to ViewModel but don't know how to to do it. This is my AuthorizatioVC.swift: class AuthorizationViewController: UIViewController { let disposeBag…
Marina
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Purpose of Disposables.create() in RxSwift

I'm learning RxSwift and I've come across the following pattern when creating Observables: return Observable.create { observer in let disposable = Disposables.create() // Do some stuff with observer here return disposable } As far as…
mike
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RxSwift map and flatMap difference

I can't understand the difference between map and flatMap In RxSwift. In the RxSwift playground examples and the books, flatMap is used as converting Observables which has inner Observable property. However I see flatMap being used directly on…
Meanteacher
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Can I raise an Error from rxSwift map-Function

Can I raise an error from a map function or do I need to use flatMap? The error should be reported to onError. In RxJava I can simply throw an exception. How can I do the following (pseudo-)code observable.map( value -> {if (value.isIllegal)…
Benjamin Mesing
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Observe array in Swift 3 using RxSwift

To create an observable array using RxSwift in Swift 2, I use to do this: [1, 2, 3].toObservable().subscribeNext { print($0) } But in Swift 3, it doesn't work anymore, I got this error: Value of type '[Int]' has no member 'toObservable' How can I…
pableiros
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flatMap Not returning onCompleted

I have created below function with chaining of multiple observables however whatever I do it does not seem to call completed ? it only return the following: (facebookSignInAndFetchData()) -> subscribed (facebookSignInAndFetchData()) -> Event…
Peter Pik
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Does a read only BehaviorSubject interface exist in RX and if not, is it a bad idea to make one?

Implementations of rx provide BehaviorSubject and Variable as mechanisms for modeling properties that change over time (a useful replacement for C# INotifyPropertyChanged). Generally these are exposed as Observable but it would be more…
Cargowire
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RxSwift: Return a new observable with an error

I have a function that return a Bool Observable depending if it was ok or not. func test() -> Observable { if everythingIsOk { return just(true) } return just(false) <- how can i here return a custom error to retrieve what…
Godfather
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RxSwift: Use Zip with different type observables

I'm using RxSwift 2.0.0-beta How can I combine 2 observables of different types in a zip like manner? // This works [just(1), just(1)].zip { intElements in return intElements.count } // This doesn't [just(1), just("one")].zip {…
GDanger
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Difference between `.drive()` and `.bind(to:)`

I am learning RxSwift at the moment. When would you use .drive(something) and when .bind(to: something)? Example: let disposeBag = DisposeBag() let isEnabled = BehaviorRelay(value: true) let button = UIButton() // what is the benefit of…
Dich1944
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RXSwift Not subscribing on Main Thread

I am trying to make several API calls and populate a Realm Database. Everything works fine. However when I try to run performSegue() on subscribe() method an exception is raised, informing that I can't do this on a background thread, which is…
Exprove
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RxCocoa - Why doesn't PublishRelay have an asDriver() method?

On RxCocoa I was wondering why the PublishRelay doesn't have an asDriver() method like the BehaviorRelay ? Currently if I want to convert the publishRelay into a Driver, I have to specify what to return in case of error which seems weird given that…
Bioche
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Error "nil requires a contextual type" using Swift

I'd like to achieve the following in code: class MyService { let mySubject = BehaviorSubject(value: nil) //.... } Unfortunately, I get the "nil requires a contextual type" error. I want the subject to be "empty" till I actually…
breakline
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RxSwift double mapping in tableView.rx.itemSelected

I want to get object from tableView.rx.itemSelected and after process it. This method return IndexPath, so I can map this value. But how to get object at index from the ViewModel? struct ViewModel { var items: Observable<[Item]> } Approximate I…
biloshkurskyi.ss
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