@monstermann/fn/dist/array/setAtOrElse.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/setAtOrElse.ts
/**
* `setAtOrElse(target, idx, value, orElse)`
*
* Sets the value at the specified `idx` in `target` to `value`. If the index is out of bounds, calls `orElse` with the original array.
*
* ```ts
* setAtOrElse([1, 2, 3], 1, 9, () => []); // [1, 9, 3]
* setAtOrElse([1, 2, 3], -1, 9, () => []); // [1, 2, 9]
* setAtOrElse([1, 2, 3], 5, 9, (arr) => arr); // [1, 2, 3]
* ```
*
* ```ts
* pipe(
*     [1, 2, 3],
*     setAtOrElse(1, 9, () => []),
* ); // [1, 9, 3]
* pipe(
*     [1, 2, 3],
*     setAtOrElse(-1, 9, () => []),
* ); // [1, 2, 9]
* pipe(
*     [1, 2, 3],
*     setAtOrElse(5, 9, (arr) => arr),
* ); // [1, 2, 3]
* ```
*/
const setAtOrElse = dfdlT((target, idx, value, orElse) => {
	const offset = resolveOffset(target, idx);
	if (offset < 0) return orElse(target);
	if (is(target[offset], value)) return target;
	target = cloneArray(target);
	target.splice(offset, 1, value);
	return target;
}, 4);

//#endregion
export { setAtOrElse };