how to mixup 2 class in javascript?
<p>Here are two JavaScript classes written by others, I need to use both of them:</p>

<ol>
<li><a href="https://github.com/chriso/node-validator/blob/master/lib/filter.js" rel="nofollow">filter.js</a></li>
<li><a href="https://github.com/chriso/node-validator/blob/master/lib/validator.js" rel="nofollow">validator.js</a></li>
</ol>

<p>I need to mix them up into a single class - it could be Validator or Filter class, or some class I define but I have to do this after Validator Filter initialized.</p>
