Inline if and hash

controllers.application.js

import Ember from 'ember';
const { set } = Ember;

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  init() {
  	this.renderFirst = false;
  },
  
  actions: {
    toggle() {
      set(this, 'renderFirst', !this.renderFirst);
    }
  }
});

styles.app.css

body {
  margin: 12px 16px;
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  font-size: 12pt;
}

dd {
  font-style: italic;
}

dt {
  font-weight: bold;
}

dt:after {
  content: ":";
}

dd, dt {
  display: inline-block;
}

templates.application.hbs

<h1>Inline if + contextual component</h1>
<p>Demonstrates that it's broken for ember less than @2.10</p>
<br>

{{outlet}}

<dl>
	<dt>Current Value</dt>
	<dd>{{renderFirst}}</dd>
</dl>

<button onclick={{action "toggle"}}>
	Toggle Component
</button>

<br />
<br />

<fieldset>
  <legend>Current Component</legend>
  {{#contextual-cmp 
	  renderFirst=renderFirst 
	  as |options|
  }}
    {{options.cmp}}
  {{/contextual-cmp}}
</fieldset>

templates.components.cmp-1.hbs

{{yield}}

Component 1

templates.components.cmp-2.hbs

{{yield}}

Component 2

templates.components.contextual-cmp.hbs

{{yield (hash 
  cmp=(if renderFirst 
  	(component "cmp-1") 
    (component "cmp-2")
  )
)}}

twiddle.json

{
  "version": "0.11.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.10.2",
    "ember-data": "2.11.0",
    "ember-template-compiler": "2.10.2",
    "ember-testing": "2.10.2"
  },
  "addons": {}
}