import CompoundWithState from './compound_with_state';
import type { NullableState, Traverser, Schema } from '../types';
declare class Nullable<T> extends CompoundWithState<T | null, T | null, NullableState<T | null, T | null, T>> {
    constructor(state: NullableState<T | null, T | null, T>);
    filter(value: unknown, defaultable: false, quiet: true): boolean;
    filter(value: unknown, defaultable?: boolean, quiet?: false): T | null;
    filter(value: unknown, defaultable?: boolean, quiet?: boolean): T | null | boolean;
    test(value: unknown): value is T | null;
    traverse(traverser: Traverser, parent?: Schema, key?: string | number): void;
}
export default Nullable;