n</code> will not be invoked unless all dependency property 
values have been defined (if any property values are
<code>undefined</code>, <code>fn</code> will not be invoked).</p>
</li>
<li><p><code>thisArg</code> (optional) The object used as <code>this</code> when invoking <code>fn</code>.</p>
</li>
</ul>
<p>Note that <code>fn</code> is invoked on the next tick of the JavaScript
event loop, both for initialization and for dependency property updates.</p>
<p>Note also that sequential changes to multiple de