import type { Fn } from "@thi.ng/api";
import type { Reducer } from "./api.js";
/**
 * Reducer. Computes histogram of given inputs. Returns a Map with unique inputs
 * as keys and their occurrences as values.
 */
export declare function frequencies<A>(): Reducer<A, Map<A, number>>;
export declare function frequencies<A>(src: Iterable<A>): Map<A, number>;
export declare function frequencies<A, B>(key: Fn<A, B>): Reducer<A, Map<B, number>>;
export declare function frequencies<A, B>(key: Fn<A, B>, src: Iterable<A>): Map<B, number>;
//# sourceMappingURL=frequencies.d.ts.map