title: node formidable rename directory path from form fields
body: <p>I need to set the file upload path based on form field values in a formidable form upload that has both the file and fields ( multipart form type).</p>
  
  <p>theForm.on('fileBegin', function (name, file){ ...}
  is called before
  theForm.parse(req, function(err, fields, files) { ... }</p>
  
  <p>However, it seems that the form upload path must be set before the form fields are parsed.  And so I don't see a way to access properties in  fields yet.  Theres nothing there yet except for prototype.  I also looked in req.body but the values aren't there either.  </p>
  
  <p>Is this correct?  Is there a way to change the form upload path after the form fields are available, but before the file is then saved to disk?</p>
  
  <p>I am using the most current of everything as of today, 7/31/2017.</p>
  
  <p>I also have body-parser in use, to read in JSON..  Could that be causing this issue? ( I've read that it is and also is NOT okay to use it- removing it causes other issues for me, so I've left it in so far .. )
  const bodyParser = require('body-parser');
  const jsonParser = bodyParser.json();</p>
  
  <p>Many thanks!</p>