/**
 * @since 1.0.0
 */
import type { Pipeable } from "@effect/data/Pipeable";
import type { Predicate } from "@effect/data/Predicate";
import type * as Queue from "@effect/io/Queue";
import type * as Stream from "@effect/stream/Stream";
import type * as Take from "@effect/stream/Take";
/**
 * @since 1.0.0
 * @category symbols
 */
export declare const GroupByTypeId: unique symbol;
/**
 * @since 1.0.0
 * @category symbols
 */
export type GroupByTypeId = typeof GroupByTypeId;
/**
 * Representation of a grouped stream. This allows to filter which groups will
 * be processed. Once this is applied all groups will be processed in parallel
 * and the results will be merged in arbitrary order.
 *
 * @since 1.0.0
 * @category models
 */
export interface GroupBy<R, E, K, V> extends GroupBy.Variance<R, E, K, V>, Pipeable {
    readonly grouped: Stream.Stream<R, E, readonly [K, Queue.Dequeue<Take.Take<E, V>>]>;
}
/**
 * @since 1.0.0
 */
export declare namespace GroupBy {
    /**
     * @since 1.0.0
     * @category models
     */
    interface Variance<R, E, K, V> {
        readonly [GroupByTypeId]: {
            readonly _R: (_: never) => R;
            readonly _E: (_: never) => E;
            readonly _K: (_: never) => K;
            readonly _V: (_: never) => V;
        };
    }
}
/**
 * Run the function across all groups, collecting the results in an
 * arbitrary order.
 *
 * @since 1.0.0
 * @category destructors
 */
export declare const evaluate: {
    <K, E, V, R2, E2, A>(f: (key: K, stream: Stream.Stream<never, E, V>) => Stream.Stream<R2, E2, A>, options?: {
        readonly bufferSize?: number;
    }): <R>(self: GroupBy<R, E, K, V>) => Stream.Stream<R2 | R, E | E2, A>;
    <R, K, E, V, R2, E2, A>(self: GroupBy<R, E, K, V>, f: (key: K, stream: Stream.Stream<never, E, V>) => Stream.Stream<R2, E2, A>, options?: {
        readonly bufferSize?: number;
    }): Stream.Stream<R | R2, E | E2, A>;
};
/**
 * Filter the groups to be processed.
 *
 * @since 1.0.0
 * @category utils
 */
export declare const filter: {
    <K>(predicate: Predicate<K>): <R, E, V>(self: GroupBy<R, E, K, V>) => GroupBy<R, E, K, V>;
    <R, E, V, K>(self: GroupBy<R, E, K, V>, predicate: Predicate<K>): GroupBy<R, E, K, V>;
};
/**
 * Only consider the first `n` groups found in the `Stream`.
 *
 * @since 1.0.0
 * @category utils
 */
export declare const first: {
    (n: number): <R, E, K, V>(self: GroupBy<R, E, K, V>) => GroupBy<R, E, K, V>;
    <R, E, K, V>(self: GroupBy<R, E, K, V>, n: number): GroupBy<R, E, K, V>;
};
/**
 * Constructs a `GroupBy` from a `Stream`.
 *
 * @since 1.0.0
 * @category constructors
 */
export declare const make: <R, E, K, V>(grouped: Stream.Stream<R, E, readonly [K, Queue.Dequeue<Take.Take<E, V>>]>) => GroupBy<R, E, K, V>;
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