import * as O from 'fp-ts/lib/Option';
export * from 'fp-ts/lib/Set';
/**
 * Returns one element of a set, or `none` if the set is empty.
 *
 * Strictly speaking this is roughly the same as `head`, since ES Sets are
 * actually OrderedSets.
 */
export declare const one: <T>(ts: Set<T>) => O.Option<T>;
/**
 * Partitions a set of objects by the values of some property of that object.
 *
 * @example
 * const objs = new Set([{ foo: 1 }, { foo: 2 }, { foo: 1 }])
 * partitionBy('foo')(objs) => [Set([{foo: 1}, {foo:1}]), Set([{foo:2}])]
 */
export declare const partitionBy: <K extends string>(key: K) => <V, T extends { [k in K]: V; }>(ts: Set<T>) => Set<T>[];