message.js

export default Component.extend({
  tagName: 'time',

  tick: function() {
    this.nextTick = run.later(this, function() {
      this.notifyPropertyChange('timeago');
      this.tick();
    }, 1000);
  }.on('init'),

  // Compare message date to current. If it has been less than 2 hours ago
  // we use relative time otherwise we show the day + time.
  timeAgoString: function() {
    var now = new Date();
    var date = this.get('date');

    // Handles the slight out of sync clocks than can result in
    // showing `in a few seconds` instead of `a few seconds ago`.
    date = date > now ? now : date;

    var elapsedTime = now - date;

    if (elapsedTime < TWO_HOURS) {
      return moment(date).fromNow();
    }

    if (elapsedTime < TWO_DAYS) {
      return moment(date).format('ddd, h:m A');
    }

    return moment(date).format('MMM, DD h:m A');

  }.property('timeago'),

  willDestroyElement: function() {
    run.cancel(this.get('nextTick'));
  },
});