Rule proposal: `prefer-change-array-by-copy`

Description

array.reverse();

array.sort();

const array = [...foo];
array.splice(0, 1);

const array = [...foo];
array[1] = 'changed';

array = array.toReversed();

array = array.toSorted();

const array = foo.toSpliced(0, 1);

const array = foo.with(1, 'changed');

Contributor guide

Tech stack

javascriptnodejs

Domain

toolingdeveloper experience

Issue type

feature

DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.

3

Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.

3-5 days

Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.

stale

ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.

clear

Prerequisites

ESLint rule developmentAST traversalJavaScript array methods

Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.

40

Research direction

Study existing rules in the eslint plugin unicorn repository, especially those that detect mutable array methods like 'prefer array flat map' or 'no array method this argument'. Examine the AST selectors for calls to reverse(), sort(), splice(), and direct array index assignment. Check the issue comments for any consensus on the rule's scope and whether it should also handle cases like `array[1] = 'changed'`.