client-app.js

Template.CommentAdd.events({
  'submit form': function(e, tmpl) {
    e.preventDefault();
    formEl = tmpl.find('form');
    comment = tmpl.find('[name=comment]').value;
    if (comment.trim().length == 0) { return false; };
    Comments.insert({
      login: Meteor.user().profile.login,
      timestamp: new Date,
      room: Session.get('activeRoom'),
      comment: comment
    }, function(err, res) {
      if (err) { throw err };
      console.log('Inserted comment', res);
    });
    formEl.reset();
    chatCount.set($('.comment-item').length);
  }
});
chatCount = new ReactiveVar;
Tracker.autorun(function() {
  Session.get('activeRoom');
  chatCount.get();
  var newHeight = $('.comment-list').height();
  $('.main-list').animate({scrollTop: newHeight}, 'slow');
});
Template.CommentItem.onRendered(function() {
  chatCount.set($('.comment-item').length);
});