import type { AsyncTransformFn } from '../../internal/function.js';
import { type Undefinable, type NotUndefined } from '../core/undefinable.js';
/**
 *  Return the result of _transformer_ with using _input_ as an argument for it if _input_ is not `undefined`.
 *  Otherwise, return _defaultValue_.
 *
 *  Basically, this operation is a combination `map()` and `unwrapOr()`.
 *
 *  * `U` must not be `Undefinable<*>`.
 *      * If the result of _transformer_ is `undefined`, this throw an `Error`.
 *      * If the result of _defaultValue_ is `undefined`, this throw an `Error`.
 *  * If you'd like to accept `Undefinable<*>` as `U`, use a combination `andThen()` and `or()`.
 */
export declare function mapOrAsyncForUndefinable<T, U>(input: Undefinable<T>, defaultValue: NotUndefined<U>, transformer: AsyncTransformFn<T, NotUndefined<U>>): Promise<NotUndefined<U>>;