@monstermann/fn/dist/array/findReplaceLastOr.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/findReplaceLastOr.ts
/**
* `findReplaceLastOr(array, predicate, replacement, fallback)`
*
* Finds the last element in `array` that satisfies the provided `predicate` function and replaces it with `replacement`, returning a new array with the replaced element, or `fallback` if no element is found.
*
* ```ts
* findReplaceLastOr([1, 2, 3, 4], (x) => x > 10, 99, []); // []
* ```
*
* ```ts
* pipe(
*     [1, 2, 3, 4],
*     findReplaceLastOr((x) => x > 10, 99, []),
* ); // []
* ```
*/
const findReplaceLastOr = dfdlT((target, predicate, replacement, or) => {
	const idx = target.findLastIndex(predicate);
	if (idx === -1) return or;
	const prev = target[idx];
	if (is(prev, replacement)) return target;
	const result = cloneArray(target);
	result.splice(idx, 1, replacement);
	return result;
}, 4);

//#endregion
export { findReplaceLastOr };