When is it desirable to use for...in with Javascript?
<p>I've read plenty of reasons not to use for-in in Javascript, such as for iterating through arrays.</p>

<p><a href="http://stackoverflow.com/questions/500504/javascript-for-in-with-arrays">http://stackoverflow.com/questions/500504/javascript-for-in-with-arrays</a></p>

<p>So in what use cases is it considered ideal to use for-in in JS?</p>
