import type { SchemaValue } from '../schema.js';
export type PrimitivesValues = boolean | number | string | object | undefined | null;
export interface ValueConfig<T> {
    default?: (() => T) | T;
    required?: boolean;
}
export declare class Value<T> implements SchemaValue<T> {
    private baseConfig;
    constructor(baseConfig?: ValueConfig<T>);
    validate(value: unknown): "value is required." | null;
    get default(): T | undefined;
    get required(): boolean;
}
export declare function isUndefined(value: unknown): value is undefined;
export declare function isNull(value: unknown): value is null;
export declare function isNullOrUndefined(value: unknown): value is null | undefined;