import type { PropOptionsGenerator } from '../types';
import type { Validator } from '../validators';
/**
 * Allows any number (validated at runtime and compile time).
 *
 * @template T - can be used to restrict the type at compile time with a union type.
 * @param validator - Optional function for further runtime validation; should return `undefined` if valid, or an error string if invalid.
 */
export declare const numberProp: <T extends number = number>(validator?: Validator) => PropOptionsGenerator<T>;