What does ‘object.function’ means in Javascript?

I have quite a hard time understanding this expression (split in italic) Can someone explain it to me:
I understand ‘this’ referring to an object but in this case then what does ‘object.function’ means ?

class Chronometer {
  constructor() {
   this.currentTime = 0
   this.intervalId = null
  }

getMinutes() {
    return this.currentTime/60
  }

 getSeconds() {
    return this.currentTime%60
  }

computeTwoDigitNumber(value) {
     return String("0" + value).slice(-2)
  }

*split () {
      var minutes = this.computeTwoDigitNumber(this.getMinutes());
      var seconds = this.computeTwoDigitNumber(this.getSeconds());
      printSplit(minutes, seconds)*