Function serializeSSEEvent

packages/shared/external-annotation.ts:38–40

(event: ExternalAnnotationEvent<T>)

/** Encode an event as an SSE `data:` line. */
export function serializeSSEEvent<T>(event: ExternalAnnotationEvent<T>): string {
  return `data: ${JSON.stringify(event)}\n\n`;
}

// ---------------------------------------------------------------------------
// Input validation — shared helpers