import { type Result } from '../plain_result/result.js';
import { type Undefinable } from './undefinable.js';
/**
 *  Return `Err<void>` if _input_ is `undefinable`.
 *  Otherwise, return `Ok<T>` directly.
 */
export declare function toResultOkFromUndefinable<T>(input: Undefinable<T>): Result<T, void>;
/**
 *  Return `Ok<void>` if _input_ is `undefinable`.
 *  Otherwise, return `Err<E>` directly.
 */
export declare function toResultErrFromUndefinable<E>(input: Undefinable<E>): Result<void, E>;