secondsToDuration.js

var secondsToDuration = function (totalSeconds) {
	var str = '', oneDay = 86400, oneHour = 3600, oneMinute = 60,
		days = Math.floor(totalSeconds / oneDay),
		hours = Math.floor((totalSeconds % oneDay) / oneHour),
		minutes = Math.floor((totalSeconds % oneHour) / oneMinute),
		seconds = totalSeconds % oneMinute;

	str += (days > 0) ? days + ' days ' : '';
	str += (hours + days > 0) ? hours + 'h ' : '';
	str += (minutes + hours + days > 0) ? minutes + 'm ' : '';
	str += seconds + 's';

	return str;
};

console.log(secondsToString(867612));