import type { StateChange, StateChangeTransformation } from '../types';
import type { Stream } from '../stream';
import { BaseTransformation } from './base-transformation';
export declare class StreamMapping<T> extends BaseTransformation<T> {
    by<U>(transformation: StateChangeTransformation<T, U>): Stream<U>;
    toBoolean(value: boolean): Stream<boolean>;
    nonInitialChanges(): Stream<StateChange<T>>;
    empty(value: T | StateChangeTransformation<T, T>): Stream<T>;
}