import { type Nullable, type NotNull } from './nullable.js';
/**
 *  Return _input_ as `T` if the passed _input_ is not `null`.
 *  Otherwise, return _defaultValue_.
 *
 *  * _defaultValue_ must not be `Nullable<*>`.
 *  * If the _defaultValue_ is `null`, throw `TypeError`.
 */
export declare function unwrapOrForNullable<T>(input: Nullable<T>, defaultValue: NotNull<T>): NotNull<T>;