Function isFastifyReply

packages/nestjs/src/index.ts:240–245

* Type guard for Fastify with unique checks

(res: unknown)

 * Type guard for Fastify with unique checks
 */
function isFastifyReply(res: unknown): res is FastifyReply {
  return (
    typeof (res as FastifyReply)?.code === "function" &&
    typeof (res as FastifyReply)?.headers === "function"
  );
}