title: NodeJS res.send not returning variable value
body: <p>I'm working on a NodeJS/Express program and I'm trying to get a POST request to return data. When I return a direct string, I get the correct response.</p>
  
  <pre><code>app.post("/DoStuff", function(req, res, Data) {
    DoStuf.DoStuffFunction(req.body.UserID, function(label) {
      Data = label
      })
      res.send({message: "Stuff"});
    })
  </code></pre>
  
  <p>When I change it to return a variable (which is still a string) it only returns "{}".</p>
  
  <pre><code>app.post("/DoStuff", function(req, res, Data) {
    DoStuf.DoStuffFunction(req.body.UserID, function(label) {
      Data = label
      })
      res.send({message: Data});
    })
  </code></pre>
  
  <p>Even when I make Data = "foo" the response is "{}"</p>