New Twiddle

components.my-component.js

import Ember from 'ember';

const messages = ['msg1', 'msg2'];

export default Ember.Component.extend({
  init() {
  	this._super();
    this.set('errorCodes', Ember.Object.create());
  },
  actions: {
  	validate() {
      this.set('errorCodes.errorMessage', messages.pop());
    }
  }
});

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>
{{outlet}}
<br>
<br>
{{#my-component as |errorMessage|}}
  {{#if errorMessage}}
     {{errorMessage}}
  {{/if}}
{{/my-component}}

templates.components.my-component.hbs

{{yield errorCodes.errorMessage}}

{{input
 key-up=(action 'validate')
}}

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"
  }
}