/**
 * Encode a `Buffer` / `Uint8Array` as unpadded base64url.
 *
 * @param {Buffer | Uint8Array} bytes
 * @returns {string}
 */
export function encode(bytes: Buffer | Uint8Array): string;
/**
 * Encode a UTF-8 string as unpadded base64url.
 *
 * @param {string} text
 * @returns {string}
 */
export function encodeString(text: string): string;
/**
 * Encode a JSON-serialisable value as unpadded base64url of its
 * UTF-8 JSON representation.
 *
 * @param {unknown} value
 * @returns {string}
 */
export function encodeJson(value: unknown): string;
/**
 * Decode an unpadded base64url string into a `Buffer`. Rejects strings
 * containing padding, whitespace, or non-alphabet characters, and
 * rejects non-canonical encodings via a roundtrip check.
 *
 * @param {string} text
 * @returns {Buffer}
 */
export function decode(text: string): Buffer;
/**
 * Decode base64url and interpret the result as UTF-8.
 *
 * @param {string} text
 * @returns {string}
 */
export function decodeString(text: string): string;
/**
 * Decode base64url and parse the result as JSON. Header failures are
 * tagged {@link ErrorCode.INVALID_HEADER} so callers get an actionable code.
 *
 * @param {string} text
 * @returns {unknown}
 */
export function decodeJson(text: string): unknown;