/**
 * mapTree is like Array.prototype.map but for objects
 * applies mapping function deeply
 * mapping function allows to change object greatly, so be careful
 *
 * @param input {object}
 * @param fn {function} ({ key: string, value: any, parent: object, path: string }) => any
 * @returns {object}
 * @example
 *
 * const mapped = mapTree({
 *  a: 1,
 *  b: {
 *    c: 2
 *  }
 * }, ({ key, value }) => {
 *   if (key === 'b') {
 *     return { batman: { ...value, c: value.c * 2 } }
 *   }
 * })
 *
 * console.log(mapped) // <=
 * {
 *   a: 1,
 *   batman: {
 *     c: 4
 *   }
 * }
 */
export declare const mapTree: (input: object, fn?: (a: {
    key: string;
    value: unknown;
    parent: object;
    path: string;
}) => unknown, path?: string) => object;