import { Operator, Stream } from '../index';
export declare class DropRepeatsOperator<T> implements Operator<T, T> {
    ins: Stream<T>;
    type: string;
    out: Stream<T>;
    isEq: (x: T, y: T) => boolean;
    private v;
    constructor(ins: Stream<T>, fn: ((x: T, y: T) => boolean) | undefined);
    _start(out: Stream<T>): void;
    _stop(): void;
    _n(t: T): void;
    _e(err: any): void;
    _c(): void;
}
/**
 * Drops consecutive duplicate values in a stream.
 *
 * Marble diagram:
 *
 * ```text
 * --1--2--1--1--1--2--3--4--3--3|
 *     dropRepeats
 * --1--2--1--------2--3--4--3---|
 * ```
 *
 * Example:
 *
 * ```js
 * import dropRepeats from 'xstream/extra/dropRepeats'
 *
 * const stream = xs.of(1, 2, 1, 1, 1, 2, 3, 4, 3, 3)
 *   .compose(dropRepeats())
 *
 * stream.addListener({
 *   next: i => console.log(i),
 *   error: err => console.error(err),
 *   complete: () => console.log('completed')
 * })
 * ```
 *
 * ```text
 * > 1
 * > 2
 * > 1
 * > 2
 * > 3
 * > 4
 * > 3
 * > completed
 * ```
 *
 * Example with a custom isEqual function:
 *
 * ```js
 * import dropRepeats from 'xstream/extra/dropRepeats'
 *
 * const stream = xs.of('a', 'b', 'a', 'A', 'B', 'b')
 *   .compose(dropRepeats((x, y) => x.toLowerCase() === y.toLowerCase()))
 *
 * stream.addListener({
 *   next: i => console.log(i),
 *   error: err => console.error(err),
 *   complete: () => console.log('completed')
 * })
 * ```
 *
 * ```text
 * > a
 * > b
 * > a
 * > B
 * > completed
 * ```
 *
 * @param {Function} isEqual An optional function of type
 * `(x: T, y: T) => boolean` that takes an event from the input stream and
 * checks if it is equal to previous event, by returning a boolean.
 * @return {Stream}
 */
export default function dropRepeats<T>(isEqual?: ((x: T, y: T) => boolean) | undefined): (ins: Stream<T>) => Stream<T>;