Simple debouncer

Debounce.swift

func debounce<T>(delay: TimeInterval, function: @escaping (T) -> Void, complete: @escaping () -> Void = { }) -> (T) -> Void {
    let queue = DispatchQueue(label: "Debouncer")
    var current: DispatchWorkItem?
    
    return { input in
        current?.cancel()
        let new = DispatchWorkItem {
            function(input)
            complete()
        }
        current = new
        queue.asyncAfter(deadline: .now() + delay, execute: new)
    }
}

Usage.swift

struct User {
    var name: String
}

var user = User(name: "Ian")

let update = debounce(
    delay: 0.5,
    function: { (name: String) in
        print(name)
        user.name = name
    },
    complete: {
        print("New Value:", user.name)
    }
)

update("a")
update("b")
update("c")
DispatchQueue.main.asyncAfter(deadline: .now() + 1) {
    update("d")
    update("e")
}

/* OUTPUT:

c
New Value: c
e
New Value: e

*/