ContextualComponentsTriggerAction

alert-box-button.template.hbs

{{#if hasBlock}}
  {{yield}}
{{else}}
  X
{{/if}}

alert-box.component.js

import Ember from 'ember';

export default Ember.Component.extend({
  actions: {
    close: function() {
      alert('close');
    }
  }

});

alert-box.template.hbs

<div class="alert-box">
  {{yield (hash
  close-button=(component 'alert-box-button' onclick=(action 'close'))
  )}}
</div>

application.controller.js

import Ember from 'ember';

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

application.template.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
      {{#alert-box as |box|}}
        One Form
        {{#box.close-button}}
          Hit here to close!
        {{/box.close-button}}
      {{/alert-box}}


{{outlet}}
<br>
<br>

twiddle.json

{
  "version": "0.4.17",
  "EmberENV": {
    "FEATURES": {}
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "beta",
    "ember-data": "https://cdnjs.cloudflare.com/ajax/libs/ember-data.js/2.2.0/ember-data.js",
    "ember-template-compiler": "beta"
  }
}