I4MI on FHIR® - fhir-resources-r4.ts

FHIR® resources, inheritance and type definitions.
Generated from the FHIR® definition JSON by the Institute of Medical Informatics (I4MI).

This is the library based on FHIR® Release 4. You may also be interested in the corresponding library for FHIR® R5: See @i4mi/fhir_r5

1 Breaking changes in version 2.0.0

If you're upgrading from version 1.x.x, you may encounter some breaking changes. These are relatively easy to fix though:

1.1 I4MIBundle.addEntry()

The addEntry() method of the I4MIBundle smart resource doesn't need the resourceType as an argument anymore (since it is implicit with the actual resource as an argument). This changes the way you call the method. You just have to remove the second argument from every call of addEntry(): Version 1.x.x (Example):

myBundle.addEntry(BundleHTTPVerb.POST, 'Observation', myObservationResource);

becomes Version 2.0.0 (Example):

myBundle.addEntry(BundleHTTPVerb.POST, myObservationResource);

Note, that also the resource you want to add to the I4MIBundle now needs to be actually of type Resource (or any type inheriting from Resource), and can not be any anymore.

1.2 Resources have fixed resourceType now

In older versions, the resourceType property of every Resource was from type string and was not mandatory. This meant that you could have e.g. an Observation resource with no resourceType property at all or with resourceType = 'Patient'. This is no longer possible with Version 2.0.0, the resourceType of an Observation resource has to be Observation.

2 Usage guide

Install with

npm i @i4mi/fhir_r4

2.1 Select fhir version

This library supports the following fhir versions:

• R4 (v4.0.1)

2.2 Using resources

How do I select the resource from a specific Version? Just import resources from the path:

import { Patient, Bundle, Practitioner, Observation, Consent, Group } from '@i4mi/fhir_r4';

Then you can use them as types or implement them.

Use as Type:

let patient: Patient = {
    resourceType: 'Patient'
    ...
}

Implement

export class MyPatient implements Patient {
    resourceType = 'Patient';

    ...
}

NOTE: You always have to set the resourceType!

2.3 Create api calls

How do I create api calls?
Import statement for using all implemented api methods

import { ApiMethods, apiCall, ApiCallResponse } from '@i4mi/fhir_r4';

Then create a method, which returns the initialized ApiMethods class. We recomment doing this in a service. You need a valid access token, the token type and the url to the fhir server. For example:

• ACCESS_TOKEN = 'eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWUsImp0aSI6IjRlMjI4YTllLWZmMTMtNDgzNy1iOWFkLTI3NzcxYjM1YWIzNyIsImlhdCI6MTU2NTM1ODc0OCwiZXhwIjoxNTY1MzYyMzQ5fQ.CAfKTeRuGWQxzFuJM7hrB2z4sHuYplP1uXm_B_zkfjM'
• TOKEN_TYPE = 'Bearer'
• FHIR_SERVER_URL = https://your-url.coop

Then create the function. It should look something like this:

/**
 * Inits the api method class
 */
private getAPI(): ApiMethods {
  return new ApiMethods({
    access_token: ACCESS_TOKEN,
    authorization_type: TOKEN_TYPE,
    base_url: FHIR_SERVER_URL + '/fhir'});
}

IMPORTANT: When the token has changed, you have to re-init the ApiMethods class.

In the now created service, implement a function which assigns the ApiMethods instance to a member.

/**
 * Execute init of API mehtods
 */
initApiMethods() {
  this.apiMethods = this.getAPI();
}

The now assigned instance this.apiMethods can be used to execute create, update, read and search. These methods are implemented according the smart on fhir implementation guidelines.

IMPORTANT: Check the allowed content type (header) of your target server. If it is different than the default "application/fhir+json;fhirVersion=4.0", call differentiateContentType([YOUR_TYPE]) BEFORE sending any request. For example:

this.apiMethods.differentiateContentType("application/fhir+json;charset=utf-8");

2.3.1 Other examples (search, create, etc.)

Search:

myStaticPatientSearch() {
    this.apiMethods.search({ _id: 1 }, 'Patient')
        .then((response) => {
            console.log(response);
        });
}

Create:

myStaticPatientCreate() {
    const myPatient: Patient = {
        resourceType: 'Patient',
        name: {
            given: [
                'Hans'
            ],
            family: 'Muster'
        }
    }

    this.apiMethods.create(myPatient, 'Patient').then(
        (response) => {
            console.log(response);
        });
}

3 Smart resources and utils

This library also provides some smart resources and utils to make your life with FHIR® easier.

3.1 I4MIBundle

This smart resource represents a Bundle, and lets you add and remove entries. First, the Bundle has to be initialized by calling const myBundle = new I4MIBundle(type), where type is the BundleType needed.

After initializing the Bundle, you can add an entry by calling myBundle.addEntry(verb, entry), where verb is the BundleHTTPVerb for the entry, and entry the resource you want to add to the Bundle. Contrary to earlier versions of the library, it is not necessary anymore to explicitly specify the resourceType.

For removing an entry from the resource, you can call myBundle.removeEntry(id), where id is the id of the resource in the entry.

3.2 Internationalization (I18N)

FHIR® supports I18N with extensions. Any text / string element can have an extensible sibling with an leading underscore, that contains the internationalization strings (e.g. if a resource has a resource.title element, the corresponding extensible element would be resource._title).

With readI18N(), getAllI18N() and writeI18N(), this library provides functions that help with interacting with this translation extensions.

readI18N(resource._title, 'en'): string allows you to read the translation string for a given element and language (in this case, the resource title in english). If the element does not have a well formed I18N extension or the respective language is not available, undefined is returned (and you have to fall back on the normal resource.title element or another a language).

getAllI18N(resource._title): {[l: string]: string} allows you to get all available translation strings for a given element. If the element does not have a well formed I18N extension or no language is available, an empty object {}is returned (and you have to fall back on the normal resource.title element).

writeI18N(translations): ExtensionElement allows you to comfortably write wellformed I18N extensions to a resource element. The 'translations' argument is a key/value pair of the languages and I18N string you want to write, as in the following example:

const translations = {
    en: 'This is the title.',
    fr: 'Voici le titre.',
    de: 'Dies ist der Titel.'
};
resource._title = writeI18N(translations);

3.3 Other util functions

The library provides some more util functions, that help with working with different simple tasks that you will encounter when using FHIR®.

hasCode(codeableConcept, coding): boolean is a helper function that searches for a given coding in a CodeableConcept and returns true if at least one of the codings in the CodeableConcept matches the code and the system (if available) of the given coding.

Example code:

const isPollenObservation = hasCoding(
    myObservation.code,     // codeable concept of e.g. an Observation
    { 
        system: 'http://snomed.info/sct', 
        code: '256277009'   // SNOMED for grass pollen
    }
);
if (isPollenObservation) {
    console.log('Resource "myObservation" is about grass pollen.');
}

getCode(codeableConcept, system): code | undefined extracts a code for a given system (e.g. 'http://snomed.info/sct' for SNOMED CT) from a CodeableConcept. If no code is available for the given system or if the CodeableConcept itself is undefined, getCode() returns undefined.

isUUID(id): boolean checks if a given Value is a valid (Universally Unique Identifier UUID)[https://en.wikipedia.org/wiki/Universally_unique_identifier] (also known als Globally Unique Identifier GUID). It returns true if the given id is an UUID / GUID, and false in every other case.

getFullName(name, exludeTitles?): string extracts the full name from a HumanName, with all given names separated by a whitespace and in the end followed by the family name. Example: Homer Jay Simpson. Set the optional excludeTitles parameter to true to omit titles in prefix and suffix.

selectName(names, priorisation?): HumanName selects the best suited HumanName from an array of multiple HumanName. If no priorisation is given, the default priorisation is USUAL > OFFICIAL > TEMP (if period is given and does match) > NICKNAME > ANONYMOUS > TEMP (if period does not match) > MAIDEN > OLD. If none of the provided HumanNames have an use poperty, the first name of the array is returned.

isInPeriod(period, time?): boolean checks if a given time point (time) is in a given period. If no time is provided, the current time is taken.

getIdentifierString(patient, system) extracts an identifier string from a Patient resource for a given identifier system. It returns a string in the form of urn:oid:1.1.1.99.1|1e3796be..., where urn:oid:1.1.1.99.1 is the system and 1e3796be... the identifier.

4 Contribution & dev guide

4.1 Build

to generate a new build in './dist/'

npm run build

4.2 Deploy

update version in package.json then

npm publish --access public

5 License & Versions

5.1 Apache 2.0

This software is published under an Apache 2.0 License.

5.2 FHIR® Trademark

FHIR® is the registered trademark of HL7 and is used with the permission of HL7. Use of the FHIR® trademark does not constitute endorsement of this product by HL7.

5.3 Changelog

You can see the history of changes in the newest versions of this library in the changelog file.