how would i create a Timer signal

[jpmhouston]

Any tips for creating a timer signal? Here's what I tried throwing together based on examples and a gesture recognizer signal I made that does work, but it doesn't fire.

public extension Signal {
    // in case of a Timer, we dont start with an object on which we bootstrap a signal
    // so add this class method on Signal itself for creating a timer signal (can we make this a convenience init instead?)
    public class func repeatingTimer(withInterval interval: TimeInterval) -> Signal<Timer> {
        let signal = Signal<Timer>()
        let observer = IntervalTimerOperator(interval: interval)
        
        observer.callback = { [weak signal] timer in
            signal?.send(timer)
        }
        
        signal.disposableSource = observer
        
        return signal
    }
}

final class IntervalTimerOperator: NSObject, Disposable {
    private var timer: Timer!
    private var isDisposed = false
    
    internal var callback: ((_ timer: Timer) -> Void)?
    
    init(interval: TimeInterval, repeats: Bool = true) {
        super.init()
        self.timer = Timer(timeInterval: interval, target: self, selector: #selector(fire(_:)), userInfo: nil, repeats: repeats)
    }
    
    func fire(_: Timer) {
        callback?(timer)
    }
    
    func dispose() {
        guard !isDisposed else { return }
        timer.invalidate()
        isDisposed = true
    }
}

[jpmhouston]

oops, needed to use Timer.scheduleTimer(..). now it works. using needs to be like:

Signal<Timer>.repeatingTimer(withInterval: interval).next { [weak self] _ in
    self?.checkTheThing()
}.disposeWith(disposalBag)

does anyone have a better suggestion for creating besides using an extension on Signal? perhaps extension on Timer itself?

[yankodimitrov]

Hi,

I think an extension on the Timer type will be cleaner:

extension Timer {
    
    public func observe() -> Signal<Void> {
       
        let signal = Signal<Void>()
        let observer = IntervalTimerOperator(interval: interval)
        
        observer.callback = { [weak signal] _ in
            signal?.send()
        }
        
        signal.disposableSource = observer
        
        return signal
    }
}

Then you can use it like this:

let timer = Timer(interval: interval)

timer.observe().next { [weak self] _ in
    self?.checkTheThing()
}.disposeWith(disposalBag)