import type { Plain } from './types';
/**
 * Converts a data structure through recursive calls to toJSON methods if they exist for each value.
 * If the method doesn't exist, the original value is returned.
 * Values for which there is no call method will remain in their original value.
 * @param value Value for conversion
 * @param recursive Perform nested processing
 * @returns The converted value
 */
export declare function plain<T>(value: T, recursive?: boolean): Plain<T>;