@monstermann/fn/dist/map/set.js

A utility library for TypeScript.

import { is } from "../function/is.js";
import { dfdlT } from "@monstermann/dfdl";
import { cloneMap } from "@monstermann/remmi";

//#region src/map/set.ts
/**
* `set(map, key, value)`
*
* Sets the `value` for the specified `key` in `map`, returning a new map if the value changes.
*
* ```ts
* set(
*     new Map([
*         ["a", 1],
*         ["b", 2],
*     ]),
*     "a",
*     10,
* ); // Map(2) { "a" => 10, "b" => 2 }
*
* set(
*     new Map([
*         ["a", 1],
*         ["b", 2],
*     ]),
*     "c",
*     3,
* ); // Map(3) { "a" => 1, "b" => 2, "c" => 3 }
* ```
*
* ```ts
* pipe(
*     new Map([
*         ["a", 1],
*         ["b", 2],
*     ]),
*     set("a", 10),
* ); // Map(2) { "a" => 10, "b" => 2 }
*
* pipe(
*     new Map([
*         ["a", 1],
*         ["b", 2],
*     ]),
*     set("c", 3),
* ); // Map(3) { "a" => 1, "b" => 2, "c" => 3 }
* ```
*/
const set = dfdlT((target, key, value) => {
	if (is(target.get(key), value)) return target;
	target = cloneMap(target);
	target.set(key, value);
	return target;
}, 3);

//#endregion
export { set };