FHIR Classes

These classes don't differ much from any other object oriented classes. If you want to create a patient for instance, you do it just like this:

final patient = Patient(
    id: FhirString('123'),
    name: [
      HumanName(
        family: 'Doe'.toFhirString,
        given: ['John'.toFhirString],
      ),
    ],
    birthDate: '1990-01-01'.toFhirDate,
  );

And that's that. So a couple of things to mention. I liked freezed, but it doesn't play well with other code generators, and ends up producing a LOT of code. And while its very useful, I didn't think we needed all of it for this, so that's gone. I did still keep most of the important parts of freezed. All classes are immutable. They all have copyWith functions. There are also some new functions, like getChildByName and fromJsonString which we'll discuss in more depth in Class Structure.

Another thing you'll notice, is that there are getters on all the primitive values. This is because FHIR puts requirements on what is considered a Url or a Date, or a DateTime and it doesn't usually align with Dart's perspective. Again, much more in-depth discussion in Primitive Types. But for now, know that there are getters for almost all of Dart's primitive types to convert them into FHIR primitive types. So you can do FhirString('123') like we did above for id, OR you can just do .toFhirString like we did for the names.