title: Is it bad practice to shadow variables of a callback?
body: <p>Take the asynchronous Node function <code>fs.stat()</code> for an example. If I need to use <code>fs.stat()</code> on a file, then do it again later, the result is shadowed.</p>
  
  <pre><code>fs.stat(file, function(err, stats) {
    fs.stat(file, function(err, stats) {
    });
  });
  </code></pre>
  
  <p>The <code>err</code> variable, as well as <code>stats</code> variable is shadowed - does this even matter if I won't be using the first callback inside the second? Is it better practice to rename the second callback variables?</p>
  
  <p>Does overwriting these variables, once, or multiple times have any performance impact?</p>