import { TransformOptions } from 'class-transformer';
/**
 * Returns `null` value for `null` string (case insensitive),
 * or the value otherwise
 * @param value
 * @returns
 */
export declare function toNull(value: unknown): {} | null | undefined;
/**
 * Returns `null` value for `null` string (case insensitive),
 * or the value otherwise
 * @returns
 */
export declare function ToNull(options?: TransformOptions): PropertyDecorator;