import { StringFormatType } from '../../utils/index';
import { ValidationContext, ValidatorBase } from '../index';
export declare const VALIDATOR_JSON_METADATA_KEY: unique symbol;
export declare function isJson(errorMessage?: StringFormatType): (target: Record<string, any>, propertyKey: string | symbol, descriptor: TypedPropertyDescriptor<any>) => void;
export declare class JsonValidator extends ValidatorBase {
    constructor(errorMessage?: StringFormatType);
    private isMatch;
    validate(context: ValidationContext<any, any>): Promise<boolean>;
}