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

A utility library for TypeScript.

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

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

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