sindresorhus/eslint-plugin-unicorn

`unicorn/prefer-at` incorrectly fixes object property key lookup

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#2,229 opened on Dec 12, 2023

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Description

for the following code:

const x = {
  1: 1,
  a: 2,
};

const y = x['a']; // can also be written as x.a 
const z = x[1];

the prefer-at rule will suggest and autofix const z = x[1]; to const z = x.at(1); - this is an object and therefore does not have the .at property available, while the x['a'] accessor remains unchanged.

While in TypeScript and Javascript, object property keys are supposed to always be strings, we cannot always assume that they are.

I believe that the rule should check whether you are accessing on an object and therefore not suggest the fix

Contributor guide

Research direction
Inspect the `prefer at` rule code to identify where the autofix is applied and add a check to ensure the object being accessed is an array or has an `at` method.
Tech stack
javascript
Domain
tooling
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
ESLint
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
75