Input Mapping

The input-mapping.ts file in a subscription trigger transforms the incoming FHIR resource event into workflow input parameters. It is the bridge between the raw Aidbox webhook payload and the typed workflow input.

Interface

Every input-mapping.ts exports:

• main(input) — required — the mapping function.
• description — required for UI — markdown description shown in the trigger list.

export const description = `# Encounter Finished

Starts prebill when an Encounter status changes to "finished".`;

interface Input {
  resource: Record<string, unknown>;   // the FHIR resource from the webhook
}

export async function main(input: Input): Promise<Record<string, unknown>> {
  const encounter = input.resource;
  return {
    _workflowId: `prebill-enc-${encounter.id}`,
    encounterId: encounter.id as string,
    tenantOrganizationId: extractOrgId(encounter),
    submissionType: "original",
  };
}

function extractOrgId(encounter: Record<string, unknown>): string {
  const ref = (encounter.serviceProvider as { reference?: string })?.reference ?? "";
  return ref.split("/")[1] ?? "";
}

The _workflowId field

The special _workflowId field controls the Temporal workflow ID for the started workflow. It is stripped from the input before the workflow receives it.

• If provided: used as the Temporal workflow ID. If a workflow with that ID is already running, Temporal rejects the new start request — this is the deduplication mechanism.
• If omitted: the ID is auto-generated as {workflowId}-trigger-{triggerId}-{timestamp}, which is always unique (no deduplication).

Set _workflowId to a resource-scoped value to ensure at most one workflow runs per resource:

return {
  _workflowId: `prebill-enc-${encounter.id}`,   // one prebill per encounter
  encounterId: encounter.id as string,
};

Resource content

By default, Aidbox delivers the full FHIR resource as the webhook payload. The destination.content field in definition.yaml controls this:

For id-only or empty, use @aidbox-billing/fhir/search inside main to fetch what you need.

Async functions

main is async — you can make FHIR API calls inside it if you need to look up related resources before constructing the workflow input.