How to format time since xxx e.g. “4 minutes ago” similar to Stack Exchange sites

Question

The question is how to format a JavaScript Date as a string stating the time elapsed similar to the way you see times displayed on Stack Overflow.

e.g.<

Answer 1

Much readable and cross browser compatible code:

As given by @Travis

var DURATION_IN_SECONDS = {
  epochs: ['year', 'month', 'day', 'hour', 'minute'],
  year: 31536000,
  month: 2592000,
  day: 86400,
  hour: 3600,
  minute: 60
};

function getDuration(seconds) {
  var epoch, interval;

  for (var i = 0; i < DURATION_IN_SECONDS.epochs.length; i++) {
    epoch = DURATION_IN_SECONDS.epochs[i];
    interval = Math.floor(seconds / DURATION_IN_SECONDS[epoch]);
    if (interval >= 1) {
      return {
        interval: interval,
        epoch: epoch
      };
    }
  }

};

function timeSince(date) {
  var seconds = Math.floor((new Date() - new Date(date)) / 1000);
  var duration = getDuration(seconds);
  var suffix = (duration.interval > 1 || duration.interval === 0) ? 's' : '';
  return duration.interval + ' ' + duration.epoch + suffix;
};

alert(timeSince('2015-09-17T18:53:23'));