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

A utility library for TypeScript.

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

//#region src/array/setAt.ts
/**
* `setAt(target, idx, value)`
*
* Sets the value at the specified `idx` in `target` to `value`. Returns the original array if the index is out of bounds or the value is already the same.
*
* ```ts
* setAt([1, 2, 3], 1, 9); // [1, 9, 3]
* setAt([1, 2, 3], -1, 9); // [1, 2, 9]
* setAt([1, 2, 3], 5, 9); // [1, 2, 3]
* ```
*
* ```ts
* pipe([1, 2, 3], setAt(1, 9)); // [1, 9, 3]
* pipe([1, 2, 3], setAt(-1, 9)); // [1, 2, 9]
* pipe([1, 2, 3], setAt(5, 9)); // [1, 2, 3]
* ```
*/
const setAt = dfdlT((target, idx, value) => {
	const offset = resolveOffset(target, idx);
	if (offset < 0) return target;
	if (is(target[offset], value)) return target;
	target = cloneArray(target);
	target.splice(offset, 1, value);
	return target;
}, 3);

//#endregion
export { setAt };