gistfile1.js

var o2x = require( 'object-to-xml' );
var j2c = require( 'json-2-csv' );
var j2t = require( 'json-2-tsv' );

function( req, res, next ) {
  if( req.accepts( 'application/json' ) ) {
    return res.json( req.payload );
  }
  if( req.accepts( 'text/xml' ) ) {
    res.set( 'content-type', 'text/xml' );
    return res.send( o2x( req.payload ) );
  }
  if( req.accepts( 'text/csv' ) ) {
    req.set( 'content-type', 'text/csv' );
    return res.send( j2c( req.payload ) );
  }
  if( req.accepts( 'text/tsv' ) ) {
    req.set( 'content-type', 'text/tsv' );
    return res.send( j2t( req.payload ) );
  }
  console.log( req.headers.accept );
  return res
    .status( 406 )
    .send( 'Not Acceptable' );
}