JavaScript seconds to time string with format hh:mm:ss

Question

I want to convert a duration of time, i.e., number of seconds to colon-separated time string (hh:mm:ss)

I found some useful answers here but they all talk about conv

Answer 1

Here's how I did it. It seems to work fairly well, and it's extremely compact. (It uses a lot of ternary operators, though)

function formatTime(seconds) {
  var hh = Math.floor(seconds / 3600),
    mm = Math.floor(seconds / 60) % 60,
    ss = Math.floor(seconds) % 60;
  return (hh ? (hh < 10 ? "0" : "") + hh + ":" : "") + ((mm < 10) && hh ? "0" : "") + mm + ":" + (ss < 10 ? "0" : "") + ss
}

...and for formatting strings...

String.prototype.toHHMMSS = function() {
  formatTime(parseInt(this, 10))
};