An action that will be debounced after a certain time in Swift.

DebouncedAction.swift

import Foundation

/// An action that will get executed after a certain amount of
/// time, if the object is still alive. If the object gets
/// deinited before the provided time, the action will never
/// get executed.
class DebouncedAction {
    
    private let action: ()-> Void
    private var onCancel: (()-> Void)?
    private let seconds: Int
    private let queue: DispatchQueue
    
    init(
        dispatchAfterSeconds seconds: Int,
        queue: DispatchQueue = .main,
        onCancel: (()-> Void)? = nil,
        action: @escaping ()-> Void)
    {
        self.action = action
        self.queue = queue
        self.seconds = seconds
        self.onCancel = onCancel
    }

    func start() {
        
        let deadline = DispatchTime.now() + DispatchTimeInterval.seconds(seconds)
        
        queue.asyncAfter(deadline: deadline) { [weak self] in
            self?.action()
        }
    }
    
    deinit {
        onCancel?()
    }
}


// MARK: - Usage:

var debouncedAction: DebouncedAction?

debouncedAction = DebouncedAction(
    dispatchAfterSeconds: 1,
    onCancel: {
        print("Cancelled!")
    },
    action: {
        print("Hey 1")
    })

debouncedAction?.start()


debouncedAction = DebouncedAction(dispatchAfterSeconds: 1) {
    print("Hey 2")
}

debouncedAction?.start()

// Console output:
// Cancelled!
// Hey 2