/**
 * Base64 for the pages flowR ships, which run in a browser and therefore have `btoa`/`atob` rather than
 * node's `Buffer`. The url-safe pair is what lets the playground keep a script in its own address, so a
 * link is the example.
 */
/** bytes as base64 */
export declare function toBase64(bytes: Uint8Array): string;
/** text as base64 in the alphabet a url carries without escaping anything, padding dropped */
export declare function toBase64Url(text: string): string;
/** the inverse of {@link toBase64Url}, `undefined` for anything that is not what it produced */
export declare function fromBase64Url(text: string): string | undefined;
/** Text as short as it goes while staying a url: compressed when that helps, plain base64 when it does not. */
export declare function packForUrl(text: string): string;
/** The inverse of {@link packForUrl}, `undefined` for anything it did not produce. */
export declare function unpackFromUrl(payload: string): string | undefined;