formatDuration method

formatDuration.js

// constraints: video 24 hours or less
export default duration => {
  const afterHours = duration % 3600;
  const hours = Math.floor(duration / 3600);
  const minutes = Math.floor(afterHours / 60);
  const seconds = Math.ceil(afterHours % 60);

  return [hours, minutes, seconds]
    .filter(o => o)
    .map(o => o > 9 ? o : '0' + o).join(':');
}