fhir_r4

pub package

A Dart implementation of the FHIR (Fast Healthcare Interoperability Resources) R4 specification. This package provides FHIR R4 resource models and utilities for serialization/deserialization, working with primitive types, polymorphic fields, and more.

Our New Online Guide!

It's still a work on progress, but I plan on outlining in-depth all of the functionality in all of the packages. Take a look! FHIR-FLI Online Tutorial

Features

  • Complete FHIR R4 Resource Models: Fully-typed Dart classes for all FHIR R4 resources generated from the official specification
  • Robust Serialization/Deserialization: Convert between Dart objects and JSON/YAML formats
  • Type-Safe Implementation: Strong typing and validation for all FHIR elements
  • Reflection-Like Capabilities: Dynamic field access and manipulation without requiring runtime reflection
  • Immutable Data Model: All classes follow immutable design patterns with copyWith functionality

Installation

dependencies:
  fhir_r4: ^0.4.1

Basic Usage

Creating FHIR Resources

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

Serialization/Deserialization

// Serialize to JSON Map
final jsonMap = patient.toJson();

// Serialize directly to JSON String (convenience method)
final jsonString = patient.toJsonString();

// Deserialize from JSON
final parsedPatient = Patient.fromJson(jsonMap);

// Deserialize directly from JSON String (convenience method)
final parsedFromString = Patient.fromJsonString(jsonString);

// YAML support
final yamlString = patient.toYaml();

Dynamic Resource Handling

// Parse any FHIR resource from JSON
final unknownResource = Resource.fromJson(jsonMap);

// Type checking
if (unknownResource is Patient) {
  // Work with Patient fields
}

Key Features

Primitive Types

All FHIR primitive types (string, integer, boolean, etc.) are implemented as Dart classes with validation and additional functionality:

// Creating primitive types
final myString = FhirString('Hello');
final myBoolean = FhirBoolean(true);
final myDateTime = FhirDateTime('2023-06-15T13:30:45Z');

// Using extension methods
final myString2 = 'Hello'.toFhirString;
final myBoolean2 = true.toFhirBoolean;

// Accessing values
final stringValue = myString.value;
final boolValue = myBoolean.valueBoolean;

Polymorphic Fields

FHIR-FLI handles polymorphic fields (fields that can contain different types) with clear conventions:

// Example with a polymorphic field
final carePlanDetail = CarePlanDetail(
  status: CarePlanActivityStatus.active,
  scheduledX: Timing(
    repeat: TimingRepeat(
      frequency: FhirPositiveInt(1),
      period: FhirDecimal(1),
      periodUnit: UnitsOfTime.d,
    ),
  ),
);

// Access polymorphic fields safely
if (carePlanDetail.scheduledTiming != null) {
  // Work with Timing
} else if (carePlanDetail.scheduledPeriod != null) {
  // Work with Period
}

FHIR "Enums"

FHIR code sets are implemented as specialized enum-like classes:

// Using predefined values
final status = AccountStatus.active;

// Accessing metadata
final displayText = status.display?.value;  // 'Active'
final system = status.system?.value;        // 'http://hl7.org/fhir/ValueSet/account-status'

Class Utility Methods

Each FHIR class includes methods for dynamic access and manipulation:

// Get field names
final fieldNames = patient.listChildrenNames();

// Get a field by name
final value = patient.getChildByName('birthDate');

// Set a field by name
final updatedPatient = patient.setChildByName('active', FhirBoolean(true));

// Modify with copyWith
final modifiedPatient = patient.copyWith(
  active: FhirBoolean(true),
);

// Deep equality check
final areEqual = patient1.equalsDeep(patient2);

License

This project is licensed under the MIT License - see LICENSE file for details.

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.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Contact us

You're always welcome to join the FHIR-FLI Slack Channel, or to contact me directly, email me at grey@fhirfli.dev.

Libraries

fhir_r4