import { ValidationOptions } from '../ValidationOptions'; export declare const IS_BASE64 = "isBase64"; /** * Checks if a string is base64 encoded. * If given value is not a string, then it returns false. */ export declare function isBase64(value: unknown): boolean; /** * Checks if a string is base64 encoded. * If given value is not a string, then it returns false. */ export declare function IsBase64(validationOptions?: ValidationOptions): PropertyDecorator;