yield to inverse

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>
{{#my-dropdown}}
  Dropdown Content
{{else}}
  Toggle
{{/my-dropdown}}

my-dropdown.component.js

import Ember from 'ember';

export default Ember.Component.extend({
  isOpen: false,

  actions: {
   toggle() {
     this.toggleProperty('isOpen');
   }
  }
});

my-dropdown.template.hbs

{{#if (hasBlock "inverse")}}
  {{yield to="invserse"}}
{{else}}
  <button onclick={{action "toggle"}}>Toggle Menu</button>
{{/if}}
{{#if isOpen}}
  <div class="dropdown">{{yield}}</div>
{{/if}}

twiddle.json

{
  "version": "0.4.11",
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.1.0",
    "ember-data": "https://cdnjs.cloudflare.com/ajax/libs/ember-data.js/1.13.11/ember-data.js",
    "ember-template-compiler": "2.1.0"
  }
}