brianpos / fhir-extension-helpers

FHIR Extension helper methods for Javascript and TypeScript

FHIR Extension Helpers

Introduction

This is an unofficial set of helper functions to ease working with FHIR Extensions in Javascript and TypeScript.

This library provides for FHIR R4:

• getExtension & getExtensions
• setExtension & addExtension
• getExtesion[Value type]Value
• clearExtensions
• hasExtension, hasExtensionAny

IMPORTANT Once things settle in, it will be deployed to the public npm registry

Example Usage

Setting a specific extension value (complex datatype properties/elements) Note: Will remove any other extensions with this extension URL too.

import exHelpers from 'fhir-extension-helpers';

let sample = { system: 'system', code: 'c', display: 'blah' };
exHelpers.setExtension(sample, { url: 'https://example.org/exturl', valueBoolean: true });

Adding an extension (will append to the extensions, not replace existing one(s))

exHelpers.addExtension(sample, { url: 'https://example.org/exturl', valueString: "test" });

Retrieving a specific untyped extension value (as first only - no warning if there are multiple values)

let result = exHelpers.getExtension(sample, 'https://example.org/exturl');

Retrieving a specific typed extension value (as first only - no warning if there are multiple values)

let result = exHelpers.getExtensionStringValue(sample, 'https://example.org/exturl');

Retrieving the collection of untyped extension values

let result = exHelpers.getExtensions(sample, 'https://example.org/exturl');

Removing all extensions with a specific URL

exHelpers.clearExtension(sample, 'https://example.org/exturl');

Setting an extension on a primitive property

let patient = { resourceType: 'Patient', birthDate: '1974-12-25' };
exHelpers.setExtension(patient._birthDate, 
    {
        url: 'http://hl7.org/fhir/StructureDefinition/patient-birthTime', 
        valueDateTime: '1974-12-25T14:35:45-05:00'
    },
    () => { return patient._birthDate = {} });

Support

TBD - there's not really much here... For questions and broader discussions, use the FHIR Implementers chat on Zulip.

Contributing

I'm welcoming contributors from the FHIR community!