import type { TransformFn } from '../internal/function.js';
import { type Result } from './result.js';
/**
 *  Maps a `Result<T, E>` to `Result<U, E>` by applying a _transformer_ function
 *  to an contained `Ok(T)` value, leaving an `Err(E)` value untouched.
 *
 *  This function can be used to compose the results of two functions.
 */
export declare function mapForResult<T, U, E>(input: Result<T, E>, transformer: TransformFn<T, U>): Result<U, E>;