Required params for NodeJS. Basic working example, needs improvements.

reqParams.js

function required(params) {
  return function (req, res, cb) {
    if (params.every(function (elem) { return req.body.hasOwnProperty(elem); }))
      cb();
    else
      res.send(400, {status:400, message: 'Missing required body parameters.'});
  };
};
 
/*
 * Routes
 */
 
// GET Some Route
app.get("/route", required(["user_string"]), function(req, res) {
  var respObj = {}
      user_string = req.body.user_string;
 
  res.writeHead(200, {'content-type': 'application/json'});
  res.end();
});