This is a very basic HL7 receiver in pure Node.js as proof of concept
It: 
  1 - receives an HL7 message on port 1337
  2 - sends back an Accept ack (fake very limited ack that I made up)
  3 - transforms the hl7 to xml (using my very ugly lib/hl7_to_xml.js file)
  4 - turns that xml into an object
  5 - prints out what should be the MRN (PID.3.1)