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

A utility library for TypeScript.

import { FnError } from "../function/FnError.js";
import { dfdlT } from "@monstermann/dfdl";

//#region src/array/findLastIndexOrThrow.ts
/**
* `findLastIndexOrThrow(target, predicate)`
*
* Returns the index of the last element in `target` that satisfies the provided `predicate` function. If no element satisfies the predicate, throws an error.
*
* ```ts
* findLastIndexOrThrow([1, 3, 2, 4], (x) => x > 2); // 3
* findLastIndexOrThrow([1, 2, 3, 4], (x) => x > 5); // throws FnError
* ```
*
* ```ts
* pipe(
*     [1, 3, 2, 4],
*     findLastIndexOrThrow((x) => x > 2),
* ); // 3
* pipe(
*     [1, 2, 3, 4],
*     findLastIndexOrThrow((x) => x > 5),
* ); // throws FnError
* ```
*/
const findLastIndexOrThrow = dfdlT((target, predicate) => {
	const idx = target.findLastIndex(predicate);
	if (idx < 0) throw new FnError("Array.findLastIndexOrThrow: No value found.", [target, predicate]);
	return idx;
}, 2);

//#endregion
export { findLastIndexOrThrow };