问我想在swift 5中用事件时间(来自我的json api)减去当前时间

EN

// use repeating scheduledTimer(withTimeInterval:repeats:block:) method for the Timer.
// Initialize the timer and save in the property for invalidating                                                                                                  
private let step: Double = 1.0                                                     
private var timer: Timer?                                                          
                                                                                   
private func initTimer() {                                                         
    let action: (Timer)-> Void = { [weak self] timer in                            
        guard let StrongSelf = self else {                                         
            return                                                                 
        }                                                                          
    }                                                                              
}                                                                                  
timer = Timer.scheduledTimer(withTimeInterval: step, repeats: true, block: action)
private func deinitTimer() {                                                       
    timer?,invalidate()                                                            
    timer = nil                                                                    
}                                                                                  
                                                                                   
// To Display                                                                      
func timeString(from timeInterval: TimeInterval) -> String {                       
    let seconds = Int(timeInterval.turncatingRemainder(dividingBy: 60))            
    let minutes = Int(timeInterval.turncatingRemainder(dividingBy: 60 * 60) / 60) 
    let hours = Int(timeInterval / 3600)                                           
    return String(format: "%.value:%.value:%.value" , hours, minutes, seconds   
}                                                                                  
                                                                                   
// Pause & Resume                                                                  
stopwatch.toggle()                                                                 
//Reset                                                                            
stopwatch.stop()