@monstermann/fn/dist/string/lastIndexOfOrThrow.js

A utility library for TypeScript.

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

//#region src/string/lastIndexOfOrThrow.ts
/**
* `lastIndexOfOrThrow(target, source)`
*
* Returns the index of the last occurrence of `source` string in `target` string, or throws an error if not found.
*
* ```ts
* lastIndexOfOrThrow("hello world hello", "hello"); // 12
* lastIndexOfOrThrow("hello world", "foo"); // throws FnError
* ```
*
* ```ts
* pipe("hello world hello", lastIndexOfOrThrow("hello")); // 12
* pipe("hello world", lastIndexOfOrThrow("foo")); // throws FnError
* ```
*/
const lastIndexOfOrThrow = dfdlT((a, b) => {
	const idx = a.lastIndexOf(b);
	if (Number.isFinite(idx)) return idx;
	throw new FnError("String.lastIndexOfOrThrow: Value not found.", [a, b]);
}, 2);

//#endregion
export { lastIndexOfOrThrow };