@monstermann/fn/dist/map/mapOrElse.d.ts

A utility library for TypeScript.

import { MapMap, OrElse } from "./internals/types.js";

//#region src/map/mapOrElse.d.ts

/**
 * `mapOrElse(map, key, transform, orElse)`
 *
 * Transforms the value at `key` in `map` using `transform`, calling `orElse` with the map if the key doesn't exist.
 *
 * ```ts
 * mapOrElse(
 *     new Map([
 *         ["a", 1],
 *         ["b", 2],
 *     ]),
 *     "a",
 *     (value) => value * 2,
 *     () => null,
 * ); // Map(2) { "a" => 2, "b" => 2 }
 *
 * mapOrElse(
 *     new Map([
 *         ["a", 1],
 *         ["b", 2],
 *     ]),
 *     "c",
 *     (value) => value * 2,
 *     (map) => map.size,
 * ); // 2
 * ```
 *
 * ```ts
 * pipe(
 *     new Map([
 *         ["a", 1],
 *         ["b", 2],
 *     ]),
 *     mapOrElse(
 *         "a",
 *         (value) => value * 2,
 *         () => null,
 *     ),
 * ); // Map(2) { "a" => 2, "b" => 2 }
 *
 * pipe(
 *     new Map([
 *         ["a", 1],
 *         ["b", 2],
 *     ]),
 *     mapOrElse(
 *         "c",
 *         (value) => value * 2,
 *         (map) => map.size,
 *     ),
 * ); // 2
 * ```
 */
declare const mapOrElse: {
  <K, V, U>(key: NoInfer<K>, transform: MapMap<K, V>, orElse: OrElse<K, V, U>): (target: Map<K, V>) => Map<K, V> | U;
  <K, V, U>(key: NoInfer<K>, transform: MapMap<K, V>, orElse: OrElse<K, V, U>): (target: ReadonlyMap<K, V>) => ReadonlyMap<K, V> | U;
  <K, V, U>(target: Map<K, V>, key: NoInfer<K>, transform: MapMap<K, V>, orElse: OrElse<K, V, U>): Map<K, V> | U;
  <K, V, U>(target: ReadonlyMap<K, V>, key: NoInfer<K>, transform: MapMap<K, V>, orElse: OrElse<K, V, U>): ReadonlyMap<K, V> | U;
};
//#endregion
export { mapOrElse };