secondsToHms(sec) {
    if (typeof sec === 'string') return sec;

    let hours = Math.floor(sec / 3600);
    let minutes = Math.floor((sec - hours * 3600) / 60);
    let seconds = sec - hours * 3600 - minutes * 60;

    if (hours < 10) {
      hours = '0' + hours;
    }

    if (minutes < 10) {
      minutes = '0' + minutes;
    }

    if (seconds < 10) {
      seconds = '0' + seconds;
    }

    return hours + ':' + minutes + ':' + seconds;
  }
Convert seconds to hh:mm:ss format
@param {number} sec - second
@return {string} hh:mm:ss result
@public