const DYNAMIC_ERROR_CODE = 'DYNAMIC_SERVER_USAGE' export class DynamicServerError extends Error { digest: typeof DYNAMIC_ERROR_CODE = DYNAMIC_ERROR_CODE constructor(public readonly description: string) { super(`Dynamic server usage: ${description}`) } } export function isDynamicServerError(err: unknown): err is DynamicServerError { if ( typeof err !== 'object' || err === null || !('digest' in err) || typeof err.digest !== 'string' ) { return false } return err.digest === DYNAMIC_ERROR_CODE }