import { Event } from "./Event";
/**
 * Async validation event which is spawned when some change of state must be validated by third parties and make
 * it possible to execute any number of validators to it, where first validator that return anything else but true
 * will be taken as a validation failure.
 */
export declare class AsyncValidationEvent<E> extends Event {
    private validators;
    constructor(type: Event['type'], data?: Event['data']);
    /**
     * Add validator in form of function which returns true if validation has passed of anything else that is taken
     * as an error.
     * @param validators
     */
    readonly addValidator: (...validators: Validator<E>[]) => number;
    /**
     * Launch validators one by one in sequence they've been added to list and halt as any returns error or we run
     * out of them.
     */
    readonly validate: () => Promise<true | E>;
}
declare type Validator<E> = () => Promise<true | E>;
export {};