title: What's the point of .slice(0) here?
body: <p>I was studying the jQuery source when I found this (v1.5 line 2295):</p>
  
  <pre><code>namespace = new RegExp("(^|\\.)" +
    jQuery.map( namespaces.slice(0).sort(), fcleanup ).join("\\.(?:.*\\.)?") + "(\\.|$)");
  </code></pre>
  
  <p>My question is, why use <code>slice(0)</code> here?</p>