import { AsyncMapper } from '@naturalcycles/js-lib';
import { TransformOpt, TransformTyped } from '../stream.model';
export interface TransformThroughOptions extends TransformOpt {
}
/**
 * Like `transformMap`, but lightweight, no concurrency, etc.
 * Inspired by `through2`
 */
export declare function transformThrough<IN = any, OUT = IN>(mapper: AsyncMapper<IN, OUT>, opt?: TransformThroughOptions): TransformTyped<IN, OUT>;