CombineCommunity / Rxcombine

subject# RxCombine

RxCombine provides bi-directional type bridging between RxSwift and Apple's Combine framework.

Note: This is highly experimental, and basically just a quickly-put-together PoC. I gladly accept PRs, ideas, opinions, or improvements. Thank you ! :)

Basic Examples

Check out the Example App in the ExampleApp folder. Run pod install before opening the project.

Installation

CocoaPods

Add the following line to your Podfile:

pod 'RxCombine'

Swift Package Manager

Add the following dependency to your Package.swift file:

.package(url: "https://github.com/CombineCommunity/RxCombine.git", from: "1.6.0")

Carthage

Carthage support is offered as a prebuilt binary.

Add the following to your Cartfile:

github "CombineCommunity/RxCombine"

I want to ...

Use RxSwift in my Combine code

RxCombine provides several helpers and conversions to help you bridge your existing RxSwift types to Combine.

Note: If you want to learn more about the parallel operators in Combine from RxSwift, check out my RxSwift to Combine Cheat Sheet (or on GitHub).

• Observable (and other ObservableConvertibleTypes) have a publisher property which returns a AnyPublisher<Element, Swift.Error> mirroring the underlying Observable.

let observable = Observable.just("Hello, Combine!")

observable
    .publisher // AnyPublisher<String, Swift.Error>
    .sink(receiveValue: { value in ... })

• Relays and Subjects can be converted to their Combine-counterparts using the toCombine() method, so you can use them as if they are regular Combine Subjects, and have them connected to your existing subjects.

let relay = BehaviorRelay<Int>(value: 0)

// Use `sink` on RxSwift relay
let combineSubject = relay.toCombine()

combineSubject.sink(receiveValue: { value in ... })

// Use `send(value:)` on RxSwift relay
combineSubject.send(1)
combineSubject.send(2)
combineSubject.send(3)

Use Combine in my RxSwift code

RxCombine provides several helpers and conversions to help you bridge Combine code and types into your existing RxSwift codebase.

• Publishers have a asObservable() method, providing an Observable<Output> mirroring the underlying Publisher.

// A publisher publishing numbers from 0 to 100.
let publisher = AnyPublisher<Int, Swift.Error> { subscriber in
    (0...100).forEach { _ = subscriber.receive($0) }
    subscriber.receive(completion: .finished)
}

publisher
    .asObservable() // Observable<Int>
    .subscribe(onNext: { num in ... })

• PassthroughSubject and CurrentValueSubject both have a asAnyObserver() method which returns a AnyObserver<Output>. Binding to it from your RxSwift code pushes the events to the underlying Combine Subject.

// Combine Subject
let subject = PassthroughSubject<Int, Swift.Error>()

// A publisher publishing numbers from 0 to 100.
let publisher = AnyPublisher<Int, Swift.Error> { subscriber in
    (0...100).forEach { _ = subscriber.receive($0) }
    subscriber.receive(completion: .finished)
}

// Convert a Publisher to an Observable and bind it
// back to a Combine Subject 🤯🤯🤯
publisher.asObservable()
         .bind(to: subject)

Observable.of(10, 5, 7, 4, 1,  6)
          .subscribe(subject.asAnyObserver())

Future ideas

• Add CI / Tests
• Carthage Support
• Bridge SwiftUI with RxCocoa/RxSwift
• Partial Backpressure support, perhaps?
• ... your ideas? :)

License

MIT, of course ;-) See the LICENSE file.

The Apple logo and the Combine framework are property of Apple Inc.