import type { TransformFn } from '../../internal/function.js';
import type { Option } from './option.js';
export type OptionTryTransformFn<in T, out U> = TransformFn<T, Option<U>>;
/**
 *  Returns `None` if the _input_ is `None`,
 *  otherwise calls _transformer_ with the value and returns the result.
 *
 *  XXX:
 *  Some languages call this operation flatmap.
 *  But we don't provide `flatMap()` as alias of this function
 *  to sort with other APIs.
 */
export declare function andThenForOption<T, U>(input: Option<T>, transformer: OptionTryTransformFn<T, U>): Option<U>;