Reactive Programming in iOS with Combine

Feb 4 2021 · Swift 5.3, macOS 11.0, Xcode 12.2

Part 4: Timing, Scheduling and Sequencing Operators

25. Timeout and measureInterval

Episode complete

Play next episode

Next
About this episode

Leave a rating/review

See forum comments
Cinema mode Mark complete Download course materials
Previous episode: 24. Debounce and Throttle Next episode: 26. Challenge: Collect Values by Time

Get immediate access to this and 4,000+ other videos and books.

Take your career further with a Kodeco Personal Plan. With unlimited access to over 40+ books and 4,000+ professional videos in a single subscription, it's simply the best investment you can make in your development career.

Learn more Already a subscriber? Sign in.

Heads up... You’re accessing parts of this content for free, with some sections shown as obfuscated text.

Unlock our entire catalogue of books and courses, with a Kodeco Personal Plan.

Unlock now

Heads up... You’re accessing parts of this content for free, with some sections shown as obfuscated text.

Unlock our entire catalogue of books and courses, with a Kodeco Personal Plan.

Unlock now

00:01The timeout operator is a special timing operator whose purpose is to semantically distinguish an actual timer from a timeout condition. Therefore, when a timeout operator fires, it either completes the publisher or emits an error you specify. In both cases, the publisher terminates. Let’s look at timeout in a demo.

let subject = PassthroughSubject<Void, Never>()

// 1
let timedOutSubject = subject.timeout(.seconds(5), scheduler: DispatchQueue.main)

let timeline = TimelineView(title: "Button taps")

let view = VStack(spacing: 100) {
  // 1
  Button(action: { subject.send() }) {
    Text("Press me within 5 seconds")
  }
  timeline
}

PlaygroundPage.current.liveView = UIHostingController(rootView: view)

timedOutSubject.displayEvents(in: timeline)

enum TimeoutError: Error {
  case timedOut
}

let subject = PassthroughSubject<Void, TimeoutError>()

let timedOutSubject = subject.timeout(.seconds(5),
                                      scheduler: DispatchQueue.main,
                                      customError: { .timedOut })


let subject = PassthroughSubject<String, Never>()

// 1
let measureSubject = subject.measureInterval(using: DispatchQueue.main)


let subjectTimeline = TimelineView(title: "Emitted values")
let measureTimeline = TimelineView(title: "Measured values")

let view = VStack(spacing: 100) {
  subjectTimeline
  measureTimeline
}

PlaygroundPage.current.liveView = UIHostingController(rootView: view)

subject.displayEvents(in: subjectTimeline)
measureSubject.displayEvents(in: measureTimeline)

let subscription1 = subject.sink {
  print("+\(deltaTime)s: Subject emitted: \($0)")
}

let subscription2 = measureSubject.sink {
  print("+\(deltaTime)s: Measure emitted: \($0)")
}

subject.feed(with: typingHelloWorld)

let subscription2 = measureSubject.sink {
  print("+\(deltaTime)s: Measure emitted: \(Double($0.magnitude) / 1_000_000_000.0)")
}

let measureSubject2 = subject.measureInterval(using: RunLoop.main)

let subscription3 = measureSubject2.sink {
  print("+\(deltaTime)s: Measure2 emitted: \($0)")
}