Why use NOT operator on anonymous function call? (a la Knockout 2.1.0)
<blockquote>
  <p><strong>Possible Duplicate:</strong><br>
  <a href="http://stackoverflow.com/questions/3755606/what-does-the-exclamation-mark-do-before-the-function">What does the exclamation mark do before the function?</a>  </p>
</blockquote>



<p>If you look at the <a href="http://cloud.github.com/downloads/SteveSanderson/knockout/knockout-2.1.0.debug.js" rel="nofollow">source code for KnockoutJS 2.1.0</a> you will see a code structure like this start on line 7:</p>

<pre><code>!function(factory) { ... }(factoryDefinition);
</code></pre>

<p>The not operator causes this expression to evaluate to <code>true</code> rather than <code>undefined</code>, but why bother?</p>
