export enum values in generated TS SDK

[gavinsharp]

Which Fern component?

SDK Generator

How important is this?

P2 - Medium (Would be helpful)

What's the feature?

Similar request to #5512, but for Typescript.

It would be nice for TS SDK consumers to be able to reference valid enum values from the generated SDK. Currently types are exported, but there are no run-time values generated that satisfy those type constraints, so SDK consumers effectively have to duplicate the enums.

Example

We have an OpenAPI spec that contains a schema with an enum property, e.g.:

components:
  schemas:
    Lang2FhirAndCreateRequest:
      type: object
      required:
        - resource
        - text
      properties:
        resource:
          type: string
          description: >
            Type of FHIR resource to create.
            Use 'auto' for automatic resource type detection, or specify a supported US Core profile.
          example: "condition-encounter-diagnosis"
          enum: [auto, appointment, condition-encounter-diagnosis, medicationrequest, careplan, condition-problems-health-concerns, coverage, encounter, observation-clinical-result, observation-lab, patient, procedure, questionnaire, questionnaireresponse, simple-observation, vital-signs]

That type is exported from our TS SDK (as phenoml.tools.Lang2FhirAndCreateRequest), but the relevant const is not available to consumers, so they don't have an easy way to access valid values for the resource parameter at runtime.

Any alternatives?

No response

Are you interested in contributing this feature?

No

[Swimburger]

The const is exported first and the type is inferred from the const:

    export const Resource = {
        Auto: "auto",
        Appointment: "appointment",
        ConditionEncounterDiagnosis: "condition-encounter-diagnosis",
        Medicationrequest: "medicationrequest",
        Careplan: "careplan",
        ConditionProblemsHealthConcerns: "condition-problems-health-concerns",
        Coverage: "coverage",
        Encounter: "encounter",
        ObservationClinicalResult: "observation-clinical-result",
        ObservationLab: "observation-lab",
        Patient: "patient",
        Procedure: "procedure",
        Questionnaire: "questionnaire",
        Questionnaireresponse: "questionnaireresponse",
        SimpleObservation: "simple-observation",
        VitalSigns: "vital-signs",
    } as const;
    export type Resource = (typeof Resource)[keyof typeof Resource];

Users should be able to access both.

[gavinsharp]

@Swimburger thanks for taking a look! It is indeed exported from src/api/resources/tools/client/requests/Lang2FhirAndCreateRequest.ts, but the parent index file (src/api/resources/tools/client/requests/index.ts) only re-exports types, so it isn't exposed via one of the package exports.

[Swimburger]

I see, I think this because occurs specifically with enum's that are defined inline in OpenAPI, and as a result, they are inlined into the Lang2FhirAndCreateRequest type.
These types are usually just types, but since the namespace contains an inlined const it contains more than just types.

We'll work on fixing this.

[Swimburger]

This has been fixed in version 3.43.4 of the TS SDK generator.
https://buildwithfern.com/learn/sdks/generators/typescript/changelog/2026/1/6#3434