nd what the original value was using the
<code>changedAttributes</code> function.  <code>changedAttributes</code> returns an object,
whose keys are the changed properties and values are an array of values
<code>[oldValue, newValue]</code>.</p>
<pre class="language-javascript line-numbers"><code class="javascript language-javascript">person<span class="token punctuation">.</span><span class="token function">get</span><span class="token punctuation">(</span><span class="token string">'isAdmin'</span><span cla