Nav-Countdown

components.nav-bar.js

import Ember from 'ember';

export default Ember.Component.extend({
  init: function() {
    // You need this whenever you override init (talks about it a bit in the docs
    this._super(...arguments);
    
    // Get the days left somehow
    var deadline = new Date();
    
    // Add it as a property on the component
    this.daysLeft = deadline;
  }
});

controllers.application.js

import Ember from 'ember';

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

templates.application.hbs

{{nav-bar}}
<br>
<br>
{{outlet}}
<br>
<br>

templates.components.nav-bar.hbs

<h3>The nav</h3>
<p>Countdown: {{daysLeft}}</p>

twiddle.json

{
  "version": "0.9.2",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.6.0",
    "ember-data": "2.6.0",
    "ember-template-compiler": "2.6.0"
  }
}