https://stackoverflow.com/questions/35479810/how-can-i-output-an-automatic-timer-using-handlebars-emberjs

components.my-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  timer: 0,

  init() {
    this._super(...arguments);
    let start = Date.now();
    
    setInterval(() => {
      var end = Date.now();
      var difference = end - start;
      console.log(difference);
      this.set('timer', difference);
    }, 1000);
  }
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{my-component}}
<br>
<br>

templates.components.my-component.hbs

{{timer}}

twiddle.json

{
  "version": "0.13.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.16.2",
    "ember-template-compiler": "2.16.2",
    "ember-testing": "2.16.2"
  },
  "addons": {
    "ember-data": "2.16.3"
  }
}