import type { Distance, DistanceFunction } from './distanceFunction.cjs';
/**
 * Match between a reference key and the closest key in a [key, value] collection:
 *
 * * `key` is the key closest to the reference key
 *
 * * `value` is the value associated with the closest key
 *
 * * `distance` is the distance between the closest key and the reference key;
 * it is always a finite value
 */
export type NearestKeyMatch<K, V> = Readonly<{
    key: K;
    value: V;
    distance: Distance;
}>;
/**
 * Given an Iterable of [key, value] entries, applies the distance function to
 * each key, finding the one closest to the input key, also returning its
 * associated value as well as the related distance; returns `undefined`
 * only when there are no successful match - that is, all the keys have +inf distance.
 *
 * Performs a full linear scan unless a distance equal to 0 is encountered, in which
 * case the function returns immediately; otherwise, the algorithm selects the
 * smallest *non-infinite* distance: if multiple keys happen to have such distance,
 * the selection order is not guaranteed.
 *
 * @param distanceFunction Returns the distance between two keys
 * @param key The key used as a reference to find the closest key
 * @param entries The [key, value] entries
 * @returns A `NearestKeyMatch` object if a closest key -
 * having a *finite distance* - exists; `undefined` otherwise
 */
export declare function findNearestKeyMatch<K, V>(distanceFunction: DistanceFunction<K>, key: K, entries: Iterable<readonly [K, V]>): NearestKeyMatch<K, V> | undefined;