Swift Timer with Block

JSBlockTimer.swift

//
//  JSBlockTimer.swift
//
//
//  Created by John Spiropoulos on 14/12/2016.
//  Copyright © 2016 John Spiropoulos. All rights reserved.
//
/*
Usage:
duration: How long do you want the timer to be active? (in seconds)
interval: The repetition interval of the timer (in seconds)

_ = JSBlockTimer(duration: 2, interval: 2, block: { (elapsedSecs) in
                UIView.animate(withDuration: 0.3, animations: {
                    self.splitPopUpImage.alpha = 0
                    
                })
            }).start()
*/
class JSBlockTimer {
    var timer = Timer()
    var block: (Int) -> ()
    
    let duration: Int
    let interval: TimeInterval
    var elapsedTime: Int = 0
    
    init(duration: Int, interval: TimeInterval, block: @escaping (Int) -> ()) {
        self.duration = duration
        self.interval = interval
        self.block = block
    }
    
    func start() {
        self.timer = Timer.scheduledTimer(timeInterval: interval,
                                                            target: self,
                                                            selector:#selector(eachSecond),
                                                            userInfo: nil,
                                                            repeats: true)
    }
    
    func stop() {
        timer.invalidate()
    }
    
    @objc func eachSecond() {
        self.elapsedTime+=1
        
        self.block(elapsedTime)
        
        if self.elapsedTime == self.duration {
            self.stop()
        }
    }
    
    deinit {
        self.timer.invalidate()
    }
}