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Rule proposal: Prefer `.at()` method for negative index access

See original GitHub issue

https://github.com/tc39/proposal-relative-indexing-method

~~We cannot do this one yet because ESLint only supports stage 4 features.~~

What should the rule name be? prefer-at-method-for-negative-index-access is the most correct, but also a mouthful.

Fail

array[array.length - 1];
array.slice(-1)[0];

Pass

array.at(-1);

Issue Analytics

State:
Created 3 years ago
Reactions:1
Comments:18 (7 by maintainers)

Top GitHub Comments

1reaction

fiskercommented, Apr 26, 2021

I think this rule should also enforce array.at(-2) over array.at(array.length - 2)

I’m going to add this to prefer-negative-index rule.

0reactions

fiskercommented, Jun 3, 2021

Added in https://github.com/sindresorhus/eslint-plugin-unicorn/pull/1331/commits/e58d47e90a117229fc82ff9a9a660b2eaffa6697,

When checkAllIndexAccess set to true:

For computed access, only if we are sure it’s a positive integer, use .at()
For String.charAt(), always report with suggestion to use .at()

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