 on itself first before checking 
the model.</p>
<p>For example, imagine you are writing a music player. You have defined
your <code>SongController</code> to represent the currently playing song.</p>
<div class="filename javascript"><div class="ribbon"></div><span>app/controllers/song.js</span><pre class="language-javascript line-numbers"><code class="javascript language-javascript"><span class="token keyword">export</span> <span class="token keyword">default</span> Ember<span class="token punctuation">.</s