/**
 * Creates a shape that is optional, possibly null, and possibly undefined.
 *
 * @category Shape
 * @example
 *
 * ```ts
 * import {nullableShape, checkValidShape, defineShape} from 'object-shape-tester';
 *
 * const myShape = defineShape({
 *     a: '',
 *     b: nullableShape(-1),
 * });
 *
 * checkValidShape({a: 'hi', b: 0}, myShape); // `true`
 * checkValidShape({a: 'hi', b: undefined}, myShape); // `true`
 * checkValidShape({a: 'hi', b: null}, myShape); // `true`
 * checkValidShape({a: 'hi'}, myShape); // `true`
 * checkValidShape({b: 0}, myShape); // `false`
 * ```
 */
export declare function nullableShape<T>(shape: T): import("../index.js").Shape<import("@sinclair/typebox").TOptional<import("@sinclair/typebox").TUnion<import("../index.js").ShapeInitSchema<T | null | undefined>[]>>>;