Function isMiddleware

packages/hono/src/utils/isMiddleware.ts:17–26

(handler: unknown)

 * their handler (e.g. `wrapSubAppMiddleware`) additionally need positional information.
 */
export function isMiddleware(handler: unknown): boolean {
  if (typeof handler !== 'function') {
    return false;
  }

  const composed = (handler as unknown as Record<string, unknown>)[COMPOSED_HANDLER];
  const original = typeof composed === 'function' ? composed : handler;

  return (original as (...args: unknown[]) => unknown).length >= 2;
}