/**
 * Return whether a filesystem path exists without blocking the event loop.
 *
 * @param filePath Absolute or relative path to check.
 * @returns `true` when the path can be accessed, otherwise `false`.
 */
export declare function pathExists(filePath: string): Promise<boolean>;
/**
 * Read a UTF-8 file when it exists and otherwise return `null`.
 *
 * @param filePath Absolute or relative file path to read.
 * @returns The UTF-8 source, or `null` when the file is missing.
 */
export declare function readOptionalUtf8File(filePath: string): Promise<string | null>;
/**
 * Extract a Node.js error code from an unknown thrown value.
 *
 * @param error Unknown error value.
 * @returns The string error code, or an empty string when unavailable.
 */
export declare function getNodeErrorCode(error: unknown): string;
/**
 * Extract a Node.js error code from an unknown thrown value when available.
 *
 * @param error Unknown error value.
 * @returns The string error code, or `undefined` when unavailable.
 */
export declare function getOptionalNodeErrorCode(error: unknown): string | undefined;
/**
 * Return whether an unknown error represents a missing filesystem path.
 *
 * @param error Unknown error value.
 * @returns `true` when the error has Node.js code `ENOENT`.
 */
export declare function isFileNotFoundError(error: unknown): boolean;