Bug

components.i-a.js

import Ember from 'ember';

export default Ember.Component.extend({
  string: "property string"
});

components.i-b.js

import Ember from 'ember';

export default Ember.Component.extend({
  logger: '',
  
  observer1: (function() {
    this.set('field1', 'B');
  }).observes('counter').on('init'),
  
  observer2: (function() {
    this.addToLog(this.get('field1'));
  }).observes('field1').on('init'),
  
  addToLog: function(str) {
    this.set('logger', (this.get('logger') + " " + str));
  }
  
});

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}}
{{i-a string="attribute string"}}
<br>
<br>

templates.components.i-a.hbs

{{string}}

templates.components.i-b.hbs

{{yield}}
{{ logger }}

twiddle.json

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