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

A utility library for TypeScript.

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

//#region src/array/replaceLastOr.ts
/**
* `replaceLastOr(target, value, replacement, or)`
*
* Replaces the last occurrence of `value` with `replacement` in `target` array. If the value is not found, returns the fallback value `or`. If value and replacement are the same, returns the original array unchanged.
*
* ```ts
* replaceLastOr([1, 2, 3, 2], 2, 5, []); // [1, 2, 3, 5]
* replaceLastOr([1, 2, 3], 4, 5, []); // []
* ```
*
* ```ts
* pipe([1, 2, 3, 2], replaceLastOr(2, 5, [])); // [1, 2, 3, 5]
* pipe([1, 2, 3], replaceLastOr(4, 5, [])); // []
* ```
*/
const replaceLastOr = dfdlT((target, value, replacement, or) => {
	if (is(value, replacement)) return target;
	const idx = target.lastIndexOf(value);
	if (idx === -1) return or;
	const result = cloneArray(target);
	result.splice(idx, 1, replacement);
	return result;
}, 4);

//#endregion
export { replaceLastOr };