import { FilterContext } from "../../filter";
export declare function base64Encode(this: FilterContext, left: unknown): string;
export declare function base64Decode(this: FilterContext, left: unknown): string;
export declare function base64UrlSafeEncode(this: FilterContext, left: unknown): string;
export declare function base64UrlSafeDecode(this: FilterContext, left: unknown): string;