FHIR.js

Node.JS library for serializing/deserializing FHIR resources between JS and XML, and validating FHIR resources. The library uses technologies that are safe for use in browser-only applications (node.js is not required).

Dependencies

q 1.4.1
underscore 1.8.3
path 0.12.7
xml-js 1.6.2

Installation

npm install fhir
or
bower install fhir-js

To use in a node.js application, require the "fhir" module.

var Fhir = require('fhir');

To use in a browser application, reference dist/bundle.js.

<script type="text/javascript" src="node_modules/fhir/dist/bundle.js"></script>
or
<script type="text/javascript" src="bower_components/fhir-js/dist/bundle.js"></script>

Basic Usage

var resource = {
  resourceType: 'Patient',
  ...
};
var fhir = new Fhir();
var xml = fhir.objToXml(resource);
var json = fhir.xmlToJson(xml);
var obj = fhir.xmlToObj(xml);
var results = fhir.validate(xml, { errorOnUnexpected: true });
results = fhir.validate(obj, {});

Decimal types

The FHIR specification requires that decimal values have arbitrary precision and be encoded in JSON as numbers. This is problematic since JavaScript numbers are 64-bit floating-point numbers that do lose precision. As a workaround:

xmlToObj keeps decimals as JavaScript strings so as to not lose precision
xmlToJson converts decimals to JSON numbers, obeying the specification. Consider using it instead of JSON.stringify(fhir.xmlToObj(xml)).
When parsing FHIR JSON strings, such as those produced by xmlToJson or other FHIR libraries, consider using an alternative to JSON.parse such as https://github.com/josdejong/lossless-json. This issue is mentioned in the FHIR specification: https://www.hl7.org/fhir/json.html#decimal

Documentation

API documentation can be found at http://lantanagroup.github.io/FHIR.js/

Implementation Notes

Compatible with FHIR Release 4 Candidate v3.2.0
FHIR profiles (within the "profiles" directory) are used to determine whether properties should be arrays, the data type and cardinality of each property, etc.. The profiles are first combined using packageProfiles.js into a single bundle of all profiles. A second pass over the profiles is performed to create a hierarchy (rather than a flat list) of the properties, and only includes information that validation is concerned about. The result of the second pass is stored in profiles/types.json and profiles/valueSets.json.

Test

npm test

bausmeier/FHIR.js