sticky-chatbox-will-update.js

import Ember from 'ember';

export default Ember.Component.extend({

  willUpdate() {
    this._super(...arguments);
    
    let box = this.$('ul')[0];
    let isScrolledToBottom = box.scrollTop + box.clientHeight === box.scrollHeight;
    
    this.set('isScrolledToBottom', isScrolledToBottom);
  },
  
  didRender() {
    this._super(...arguments);
    
    if (this.get('isScrolledToBottom')) {
      this.$('ul')[0].scrollTop = this.$('ul')[0].scrollHeight;
    }
  }

});