awesome, this reminds me we need to allow bound-classes to support multiple different keys in one directive. example:

<pre>
$('<div bound-classes="name age"></div>').render(alice).hasClass('alice'); // true
$('<div bound-classes="name age"></div>').render(alice).hasClass('20'); // true
</pre>

can you add a test like this to the repo, but remove the duplication when you do?