RxSwiftのshare*の早見表

はじめに

RxSwiftの3.5.0からshare(replay:scope:)が追加されました。
3.5.0未満のshare()、shareReplay(_:)、shareReplayLatestWhileConnected()にどう対応しているのか書いていきます。

.share()

.share(scope: .forever)

.shareReplay(1)

.share(replay: 1, scope: .forever)

.shareReplayLatestWhileConnected()

.share(replay: 1, scope: .whileConnected)

参考

RxSwift 3.5.0 Release Note

RxSwift/Observables/ShareReplayScope.swift

public func share(replay: Int = 0, scope: SubjectLifetimeScope)
        -> Observable<E> {
    switch scope {
    case .forever:
        switch replay {
        case 0: return self.multicast(PublishSubject()).refCount()
        default: return shareReplay(replay)
        }
    case .whileConnected:
        switch replay {
        case 0: return ShareWhileConnected(source: self.asObservable())
        case 1: return ShareReplay1WhileConnected(source: self.asObservable())
        default: return self.multicast(makeSubject: { ReplaySubject.create(bufferSize: replay) }).refCount()
        }
    }
}

追記

.share()

RxSwift/Observables/Multicast.swift

public func publish() -> ConnectableObservable<E> {
    return self.multicast(PublishSubject())
}

public func share() -> Observable<E> {
    return self.publish().refCount()
}

.shareReplayLatestWhileConnected()

RxSwift/Observables/ShareReplayScope.swift

public func shareReplayLatestWhileConnected() -> Observable<E> {
    return ShareReplay1WhileConnected(source: self.asObservable())
}