How to Debounce and Throttle Using @Observable

The expected path forward here is to combine (hey hey!) two tasks:

• Turning an observed property into an async sequence of value changes.

• Debouncing such a sequence.

The second task is covered by Swift Async Algorithms. The first task, however, is a challenge. The original SE-0395 proposed a general way to do this but that ran into problems during review. The proposal was recently accept with the async stuff moved into the Future Directions section.

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Thanks Eskimo, could you point me in a direction for the first point above ? Where do I start to turn an observed property into an async sequence of value changes ? Thanks, A

@Dionysus-Design  If you just want to debounce, you can use this code :

public actor Debouncer {
    private let duration: Duration
    private var isPending = false
    
    public init(duration: Duration) {
        self.duration = duration
    }
    
    public func sleep() async -> Bool {
        if isPending { return false }
        isPending = true
        try? await Task.sleep(for: duration)
        isPending = false
        return true
    }
}

Put this code in your Observable:

    private let debouncer = Debouncer(duration: .seconds(0.5))

    func checkEmailValidity() async {
        guard await debouncer.sleep() else { return }
        
        ... do your debounced stuff here ...
    }

And somewhere on your SwiftUI View for example:

    .onChange(of: viewModel.email) { Task { await viewModel.checkEmailValidity() } }

It seems that the timer is only set on the first key stroke. How would I reset timer to zero on each stroke to better implement debounce?