check that a collection is not empty
<p>How do you check that <code>data.results</code> in the following is not empty before trying to perform actions on it?</p>

<pre><code>$.getJSON(myurl, function(data) {
  // if data.results is not empty 
  // {
  //    console.log(data.results.size);
  // }

});
</code></pre>
