number.js

const padLeft = (number, n,str) => {
  return number.toString().length >= n ? number : Array(n-String(number).length + 1).join(str||'0') + number;
}

const playTime = (milliseconds) => {
  let seconds = milliseconds / 1000.0,
    hours = Math.floor(seconds / 3600),
    minutes = Math.floor((seconds % 3600) / 60),
    only_seconds = Math.round(seconds % 60),
    parts = [];

  if (hours >= 1)
    parts.push(padLeft(hours, 2));
  parts.push(padLeft(minutes, 2));
  parts.push(padLeft(only_seconds, 2));

  return parts.join(':');
}

export { padLeft, playTime };