Stop making HTTP requests if user has a nap

IIFE.js

(function IIFE() {
  let startDate = new Date()  
  
  // make HTTP request each 5 sec
  let newUsers_Interval = new Interval(getAmoutNewUsers, 5000)
  
  // checking each 15 min if user iteracts with page
  let userHasNap_Interval = new Interval(clearIntervalsIfUserHasANap, 900000)
  
  newUsers_Interval.start()
  userHasNap_Interval.start()
  
  $('body').click(() => {    
    startDate = new Date()        
    newUsers_Interval.start()
    userHasNap_Interval.start()
  })
  
  function Interval(fn, interval) {
    let timer
    
    this.start = () => {
      if (!timer) {        
        timer = setInterval(() => { fn() }, interval)
      }
    }
    
    this.stop = () => {
      clearInterval(timer)
      timer = void 0
    }
  }
  
  function clearIntervalsIfUserHasANap() {
    let diffMinutes = Math.round((((new Date() - startDate) % 86400000) % 3600000) / 60000)

    if (diffMinutes >= 15) {
      newUsers_Interval.stop()
      userHasNap_Interval.stop()
    }
  }    
}())