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Roadmap

The current priorities and future direction for fhir-dsl.

Current State (v0.10.0)​

What's available today:

  • Type-safe search, read, and transaction builders
  • Code generation from FHIR R4, R4B, R5, and R6 StructureDefinitions
  • Implementation Guide support (US Core and custom IGs)
  • Profile-aware queries with type narrowing
  • HTTP executor with pagination and error handling
  • Streaming and lazy loading for large datasets
  • Terminology Engine with compile-time coded value validation
  • Dual ESM/CJS builds
  • CLI for type generation

Recently Added​

Terminology Engine (v0.10.0)​

  • --expand-valuesets -- Resolves FHIR ValueSet bindings into TypeScript literal unions, turning FhirCode into FhirCode<"male" | "female" | "other" | "unknown"> for required bindings
  • --resolve-codesystems -- Generates CodeSystem namespace objects (AdministrativeGender.Female) for IntelliSense
  • Generic data types -- Coding<T> and CodeableConcept<T> support generic constraints while remaining backward-compatible
  • Offline resolution -- Pre-expanded ValueSets from the FHIR spec are downloaded and cached; no terminology server required
  • Binding strength awareness -- Required bindings produce closed unions, extensible bindings use (string & {}) for autocomplete with fallback, preferred/example bindings are left unconstrained

Streaming & Lazy Loading (v0.10.0)​

  • .stream() -- Lazy AsyncIterable that yields resources across all pages, automatically following Bundle pagination links
  • Cancellation -- AbortSignal support via stream({ signal }) for timeouts and user-initiated cancellation
  • Memory efficient -- Processes resources page-by-page without loading full datasets into memory
  • Type-safe -- Streaming preserves full type inference including profile-narrowed types

FHIRPath Expression Builder (v0.10.0)​

  • @fhir-dsl/fhirpath -- New package: type-safe FHIRPath expression builder with ~85% spec coverage
  • Expression system -- Predicate callbacks with $this proxy for where(), select(), all(), exists(), iif()
  • 60+ FHIRPath functions -- Navigation, filtering, subsetting, string, math, conversion, utility, and boolean operators
  • ofType() narrowing -- Type-safe polymorphic field handling via extensible FhirTypeMap
  • Compile + evaluate -- Build FHIRPath strings and evaluate against resources at runtime

Query Features (v0.10.0)​

  • _revinclude -- Reverse include support in search queries via .revinclude()
  • Chained parameters -- Type-safe chained search via .whereChained() (e.g., subject:Patient.name=Smith)
  • _has -- Reverse chaining for filtering via .has() (e.g., _has:Observation:subject:code=1234)
  • Composite parameters -- Type-safe .whereComposite() for multi-value composite search params with typed components (e.g., code-value-quantity)

Planned​

FHIR Operations​

  • $everything -- Patient/Encounter everything operations
  • $validate -- Resource validation against profiles
  • Custom operations -- Type-safe builder for arbitrary FHIR operations

Developer Experience​

  • Middleware/interceptors -- Hook into request/response pipeline for logging, retries, auth refresh
  • Batch support -- Type-safe FHIR batch operations (non-transactional)
  • History -- Resource and type-level history queries
  • Capabilities -- Typed access to CapabilityStatement for feature detection

Code Generation​

  • Watch mode -- Re-generate types when StructureDefinitions change
  • Custom profiles -- Generate types from your own StructureDefinitions
  • Incremental generation -- Only regenerate changed resources
  • Extension support -- First-class typed extensions

Ecosystem​

  • React hooks -- useFhirSearch, useFhirRead for React applications
  • SMART on FHIR -- Built-in auth flow integration
  • Adapter packages -- Pre-built adapters for popular FHIR servers (HAPI, Azure Health Data Services, Google Cloud Healthcare API)

Community​

Suggestions, feature requests, and contributions are welcome. Open an issue on GitHub to propose new features or discuss architectural changes.