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

A utility library for TypeScript.

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

//#region src/array/meanOrThrow.ts
/**
* `meanOrThrow(array)`
*
* Returns the mean (average) value from `array`, or throws an error if the array is empty.
*
* ```ts
* meanOrThrow([1, 2, 3]); // 2
* meanOrThrow([]); // throws FnError
* ```
*
* ```ts
* pipe([1, 2, 3], meanOrThrow()); // 2
* pipe([], meanOrThrow()); // throws FnError
* ```
*/
const meanOrThrow = dfdlT((target) => {
	if (target.length === 0) throw new FnError("Array.meanOrThrow: Target is empty.", [target]);
	return target.reduce((acc, val) => acc + val, 0) / target.length;
}, 1);

//#endregion
export { meanOrThrow };