@monstermann/fn/dist/array/union.js

A utility library for TypeScript.

import { dfdlT } from "@monstermann/dfdl";
import { cloneArray } from "@monstermann/remmi";

//#region src/array/union.ts
/**
* `union(target, source)`
*
* Returns a new array containing all unique elements from both `target` and `source`. Elements from `source` that are not already in `target` are added to the result.
*
* ```ts
* union([1, 2, 3], [3, 4, 5]); // [1, 2, 3, 4, 5]
* ```
*
* ```ts
* pipe([1, 2, 3], union([3, 4, 5])); // [1, 2, 3, 4, 5]
* ```
*/
const union = dfdlT((target, source) => {
	let result;
	for (const item of source) if (!target.includes(item)) {
		result ??= cloneArray(target);
		result.push(item);
	}
	return result ?? target;
}, 2);

//#endregion
export { union };