Debounce.swift

import PlaygroundSupport

PlaygroundPage.current.needsIndefiniteExecution = true

func debounce1<T>(delay: DispatchTimeInterval, queue: DispatchQueue = .main, action: @escaping ((T) -> Void)) -> (T) -> Void {
    var currentWorkItem: DispatchWorkItem?
    return { (p1: T) in
        currentWorkItem?.cancel()
        currentWorkItem = DispatchWorkItem { action(p1) }
        queue.asyncAfter(deadline: .now() + delay, execute: currentWorkItem!)
    }
}

func myFuncs(foo: Int) {
    print("myfunc1", foo)
}

func testDebounce() {
    let queue = DispatchQueue.global(qos: .background)
    let fn = debounce1(delay: .milliseconds(300), queue: queue, action: myFuncs)
    for i in 0...9 {
        fn(i)
        Thread.sleep(forTimeInterval: 0.2)
    }
}

// This will crash with a "Invalid pointer dequeued from free list" error.
// If the parameter in `myFuncs` is changed to a string and line 20 changed to `fn("\(i)")` it does not crash.
testDebounce()

Do you mind if I use this Gist as inspiration for a pull request for inclusion in Dollar? I will of course give attribution to you and this Gist.

https://github.com/ankurp/Dollar