Yield to Inverse

application.controller.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName:'Ember Twiddle',
  derp: false,
  
  actions: {
    underp() {
    	this.toggleProperty('derp');
    }
  }
});

application.template.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
<br>
<br>

<button {{action 'underp'}}>Underp</button>

{{#my-component thing=derp}}
  HAHAHAHA
{{else}}
	hahahaha
{{/my-component}}

my-component.component.js

import Ember from 'ember';

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

my-component.template.hbs

{{#if thing}}
  {{yield}}
{{else}}
  {{yield to="inverse"}}
{{/if}}

twiddle.json

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