Day 2 of JavaScript30

Solved the second challenge from Wes Bos “JavaScript30”.
I followed along with the video until he said stop and then continued to solve the rest, it was maybe a bit too easy after he showed the second-hand of the clock.

However, after finishing the clock I continued to refactor it and made it much more optimized than the original solution.
I choose to lift out the actual rotation of each and, setting the date only 1 time and then just add 1 second to the date for each interval instead of creating new date objects every second…

At last I fixed the minute bug by removing a class “trans” that adds the transition and adding it back in if it doesn’t exist.

Full solution:

Edited CSS

    .hand {
      position: absolute;
      -webkit-transform: rotate(90deg);
       transform: rotate(90deg);
       transition-timing-function: cubic-bezier(1, 0.01, 0.24, 1.28)
    .trans {
      transition: all 0.3s;


    const secondHand = document.querySelector('.second-hand');
    const hourHand = document.querySelector('.hour-hand');
    const minHand = document.querySelector('.min-hand');
    var now = new Date();

//Make the clock tick by adding 1 second and set each clock hand to its current position
    function rotateClock(){
      now.setSeconds(now.getSeconds() + 1);
      setHand(secondHand, now.getSeconds(), 60);
      setHand(minHand, now.getMinutes(), 60);
      setHand(hourHand, now.getHours(), 24);
//Accepts the clockhand, timing and the parts the clock-hand is divided by for full circle
    function setHand(hand, timing, dividedBy ){
      const degrees = ((timing / dividedBy) * 360) + 90;
      //avoid transition bug when it changes minute
      if(hand == secondHand && degrees == 90){
      }else if(hand == secondHand && hand.classList.contains('trans') !== true) {
      } = 'rotate(' + degrees + 'deg)';
    //Rotate the clock to the current time
    setInterval(rotateClock, 1000);

Add your comment