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

Question

function timeSince(date) {

  var seconds = Math.floor((new Date() - date) / 1000);

  var interval = seconds / 31536000;

  if (interval > 1) {
    return Math.floor(interval) + " years";
  }
  interval = seconds / 2592000;
  if (interval > 1) {
    return Math.floor(interval) + " months";
  }
  interval = seconds / 86400;
  if (interval > 1) {
    return Math.floor(interval) + " days";
  }
  interval = seconds / 3600;
  if (interval > 1) {
    return Math.floor(interval) + " hours";
  }
  interval = seconds / 60;
  if (interval > 1) {
    return Math.floor(interval) + " minutes";
  }
  return Math.floor(seconds) + " seconds";
}
var aDay = 24*60*60*1000;
console.log(timeSince(new Date(Date.now()-aDay)));
console.log(timeSince(new Date(Date.now()-aDay*2)));

Might be an overkill in this case, but if the opportunity shows moment.js is just awesome!

Moment.js is a javascript datetime library, to use it for such scenario, you'd do:

moment(yourdate).fromNow()

http://momentjs.com/docs/#/displaying/fromnow/

2018 addendum: Luxon is a new modern library and might be worth a look!

This will show you past and previous time formats like '2 days ago' '10 minutes from now' and you can pass it either a Date object, a numeric timestamp or a date string

function time_ago(time) {

  switch (typeof time) {
    case 'number':
      break;
    case 'string':
      time = +new Date(time);
      break;
    case 'object':
      if (time.constructor === Date) time = time.getTime();
      break;
    default:
      time = +new Date();
  }
  var time_formats = [
    [60, 'seconds', 1], // 60
    [120, '1 minute ago', '1 minute from now'], // 60*2
    [3600, 'minutes', 60], // 60*60, 60
    [7200, '1 hour ago', '1 hour from now'], // 60*60*2
    [86400, 'hours', 3600], // 60*60*24, 60*60
    [172800, 'Yesterday', 'Tomorrow'], // 60*60*24*2
    [604800, 'days', 86400], // 60*60*24*7, 60*60*24
    [1209600, 'Last week', 'Next week'], // 60*60*24*7*4*2
    [2419200, 'weeks', 604800], // 60*60*24*7*4, 60*60*24*7
    [4838400, 'Last month', 'Next month'], // 60*60*24*7*4*2
    [29030400, 'months', 2419200], // 60*60*24*7*4*12, 60*60*24*7*4
    [58060800, 'Last year', 'Next year'], // 60*60*24*7*4*12*2
    [2903040000, 'years', 29030400], // 60*60*24*7*4*12*100, 60*60*24*7*4*12
    [5806080000, 'Last century', 'Next century'], // 60*60*24*7*4*12*100*2
    [58060800000, 'centuries', 2903040000] // 60*60*24*7*4*12*100*20, 60*60*24*7*4*12*100
  ];
  var seconds = (+new Date() - time) / 1000,
    token = 'ago',
    list_choice = 1;

  if (seconds == 0) {
    return 'Just now'
  }
  if (seconds < 0) {
    seconds = Math.abs(seconds);
    token = 'from now';
    list_choice = 2;
  }
  var i = 0,
    format;
  while (format = time_formats[i++])
    if (seconds < format[0]) {
      if (typeof format[2] == 'string')
        return format[list_choice];
      else
        return Math.floor(seconds / format[2]) + ' ' + format[1] + ' ' + token;
    }
  return time;
}

var aDay = 24 * 60 * 60 * 1000;
console.log(time_ago(new Date(Date.now() - aDay)));
console.log(time_ago(new Date(Date.now() - aDay * 2)));

I haven't checked (although it wouldn't be hard to), but I think that Stack Exchange sites use the jquery.timeago plugin to create these time strings.

---

It's quite easy to use the plugin, and it's clean and updates automatically.

Here's a quick sample (from the plugin's home page):

First, load jQuery and the plugin:

<script src="jquery.min.js" type="text/javascript"></script> <script src="jquery.timeago.js" type="text/javascript"></script>

Now, let's attach it to your timestamps on DOM ready:

jQuery(document).ready(function() {
jQuery("abbr.timeago").timeago(); });

This will turn all abbr elements with a class of timeago and an ISO 8601 timestamp in the title: <abbr class="timeago" title="2008-07-17T09:24:17Z">July 17, 2008</abbr> into something like this: <abbr class="timeago" title="July 17, 2008">about a year ago</abbr> which yields: about a year ago. As time passes, the timestamps will automatically update.

Here is a slight modification on Sky Sander's solution that allows the date to be input as a string and is capable of displaying spans like "1 minute" instead of "73 seconds"

var timeSince = function(date) {
  if (typeof date !== 'object') {
    date = new Date(date);
  }

  var seconds = Math.floor((new Date() - date) / 1000);
  var intervalType;

  var interval = Math.floor(seconds / 31536000);
  if (interval >= 1) {
    intervalType = 'year';
  } else {
    interval = Math.floor(seconds / 2592000);
    if (interval >= 1) {
      intervalType = 'month';
    } else {
      interval = Math.floor(seconds / 86400);
      if (interval >= 1) {
        intervalType = 'day';
      } else {
        interval = Math.floor(seconds / 3600);
        if (interval >= 1) {
          intervalType = "hour";
        } else {
          interval = Math.floor(seconds / 60);
          if (interval >= 1) {
            intervalType = "minute";
          } else {
            interval = seconds;
            intervalType = "second";
          }
        }
      }
    }
  }

  if (interval > 1 || interval === 0) {
    intervalType += 's';
  }

  return interval + ' ' + intervalType;
};
var aDay = 24 * 60 * 60 * 1000;
console.log(timeSince(new Date(Date.now() - aDay)));
console.log(timeSince(new Date(Date.now() - aDay * 2)));