L7 
A simple HL7 query language and message manipulator.
Usage
Given HL7:
MSH|^~\&|REG|XYZ||XYZ|20050912110538||SIU^S12|4676115|P|2.3
PID|||353966||SMITH^JOHN^^^^||19820707|F||C|108 MAIN STREET ^^ANYTOWN^TX^77777^^|HARV|(512)555-0170|||||00362103|123-45-6789||||||||||||
SCH|1||||||NEW||||20050912110230^20050912110430||||||||||||||||||^^^^^^||3|
PV1||O|SEROT|3|||1284^JOHNSON^MIKE^S.^^MD~|||SEROT||||1|||1284^JOHNSON^MIKE^S.^^ MD|SERIES|787672|B|||||||||N||||||||||||A|||20050912110230|||||| PV2|||HAND BRACE NEEDS REPAIRED|||||||||||20050912||||||||||A||20050725|||||O||||||
NK1|0001|HULK^INCREDIBLE|M|123 FAKE ST^^OUTLAND^^00000|123456789||
NK1|0002|HULK^DEBATEABLE|M|122 FAKE ST^^OUTLAND^^00000|123456789||
And the javascript:
parser = require('L7')
message = parser.parse(hl7)
version = message.query('MSH|12') // 2.3
kinAddresses = message.query('NK1[4]') // ['123 FAKE ST^^OUTLAND^^00000', '122 FAKE ST^^OUTLAND^^00000']
kinStreets = message.query('NK1|4[0]') // ['123 FAKE ST', '122 FAKE ST']
name = message.translate({
familyName: 'PID|5^0',
firstName: 'PID|5^1'
}) // { "familyName": "McTest", "firstName": "Test" }
message.toString() // returns original message
message.replace('PID|5', 'McFake', 'Firstname'); // replaces the values in the message with the supplied ones
message.replace('PID|11^0', '123 Fake Street'); // can replace just one element
message.remove('PV1'); // removes the PV1 segment if it exists
message.remove('IN1', 'IN2'); // removes the IN1 and IN2 segments if they exists
message.remove('Z*'); // remove all "Z" segements
Installation
$ npm install L7
Caveat
This package is in its infancy, use with caution.