title: How to pass variable to a nested callback function
body: <p>I'm using <code>request</code> npm to get http pages. I have something like that</p>
  
  <pre><code>function callbackFunction1() {
    var p = 'foo';
  
    request(url, callbackFunction2);
  }
  
  function callbackFunction2(err, response, body){
  
  }
  </code></pre>
  
  <p>How could I pass the variable <code>p</code> as parameter of the callbackFunction2? </p>