如何让时钟停止

Question

I have to create two methods start and stop. Start method starts displaying current time in console in format 'hh:mm:ss' every second starting from now. Second method stops it. I am using clearInterval() to stop it but which argument should I pass there?

class Clock {

  constructor(){
    this.date = new Date()
    this.hours = this.date.getHours()
    this.minutes = this.date.getMinutes()
    this.seconds = this.date.getSeconds()
  }

  run(){
    setInterval(()=>{
      this.seconds+= 1
      if (this.seconds >= 60){
        this.minutes++
        this.seconds= 0
      }
      if (this.minutes >= 60){
        this.hours++
        this.minutes=0
      }
      if (this.hours >= 24){
        this.hours = 0
      }
      console.log(`${this.hours}:${this.minutes}:${this.seconds}`)
    }, 1000)
  }

  stop(){
    return clearInterval()
  }

}

Answer 1

In your run method, assign the number returned by setInterval to an attribute:

run(){
  this.interval = setInterval(() => { ... });
}

Later, in your stop method, pass that attribute to the clearInterval fn invocation:

stop(){
  return clearInterval(this.interval);
}

That's how it will know which interval you want to clear.