propagate data down

controllers.application.js

import Ember from 'ember';

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

editable-group-name.component.js

import Ember from 'ember';

export default Ember.Component.extend({
  oldGroupName: 'Channel 1',
  focusOut() {
  	// set value of children again as oldGroupName
	}
});

editable-group-name.template.hbs

{{group-name-input
	value=(readonly oldGroupName)
}}

group-name-input.component.js

import Ember from 'ember';

export default Ember.TextField.extend({
  
});

group-name-input.template.hbs

{{yield}}

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{editable-group-name}}
{{outlet}}
<br>
<br>

twiddle.json

{
  "version": "0.7.2",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": true,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.4.4/ember.debug.js",
    "ember-data": "https://cdnjs.cloudflare.com/ajax/libs/ember-data.js/2.4.3/ember-data.js",
    "ember-template-compiler": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.4.4/ember-template-compiler.js"
  }
}