simple debouncing in swift4

debouce.swift

import Foundation

typealias Function = () -> ()
typealias FunctionWrapper = (@escaping Function) -> ()

func debounced(time: TimeInterval, callback: @escaping Function) -> Function {
    weak var timer: Timer?
    
    return {
        timer?.invalidate()
        timer = Timer.scheduledTimer(withTimeInterval: time, repeats: false) { _ in
            callback()
        }
    }
}

func debounced(time: TimeInterval) -> FunctionWrapper {
    weak var timer: Timer?
    
    return { callback in
        timer?.invalidate()
        timer = Timer.scheduledTimer(withTimeInterval: time, repeats: false) { _ in
            callback()
        }
    }
}

usage.swift

let debouncedPrint = debounced(time: 0.5) {
    print("yes i am debounced")
}

debouncedPrint()
debouncedPrint()
debouncedPrint()

let debouncer = debounced(time: 0.8)

debouncer {
    print("first call")
}
debouncer {
    print("second call")
}
debouncer {
    print("third call")
}

// OUTPUT:
// yes i am debounced
// third call