Find duration of YouTube playlist

youtube-playlist-duration.js

var pl_times = document.getElementsByClassName('pl-video-time');
var time = 0;

function toS(hms) {
  var a = hms.split(':');
  while (a.length < 3) {
    a.unshift(0);
  }
  var seconds = (+a[0]) * 60 * 60 + (+a[1]) * 60 + (+a[2]);
  return seconds;
}

function toDHMS(totalSec) {
  var days = parseInt( totalSec / 86400 );
  var hours = parseInt( totalSec / 3600 ) % 24;
  var minutes = parseInt( totalSec / 60 ) % 60;
  var seconds = totalSec % 60;
  var result = ((days < 10 ? "0" + days : days) + "d " +
                (hours < 10 ? "0" + hours : hours) + "h " +
                (minutes < 10 ? "0" + minutes : minutes) + "m " +
                (seconds  < 10 ? "0" + seconds : seconds) + "s");
  return result;
}

for (var i = 0; i < pl_times.length; i++) {
  var pl_time = pl_times[i];
  var timestamp = pl_time.getElementsByClassName("timestamp");
  if (timestamp === undefined) { continue; } // Private video
  var vid_time = timestamp[0].children[0].textContent;
  time += toS(vid_time);
}

console.log("The full duration time is: " + toDHMS(time));