[Feature] Support ESLint v9

[theoludwig]

Reference: https://eslint.org/blog/2024/04/eslint-v9.0.0-released/

[Walidoux]

This might be handy for you as I had stumbled upon your config:

Also this comment is subject to change

• no-new-symbol deprecated and replaced by no-new-native-nonconstructor
• no-confusing-arrow deprecated in ESLint v8.53.0
• no-mixed-operators deprecated in ESLint v8.53.0
• quote-props deprecated in ESLint v8.53.0

Out of context of this issue, we might want to remove { "allowKeywords": true } for dot-notation because by default it is set to true, same for enforceForSwitchCase option key inside use-isnan, newIsCap option key inside new-cap, allowSamePrecedence option key inside no-mixed-operators

Again out of context, we might want to add enforceForJSX to true in no-unused-expressions

[theoludwig]

Related issues:

• https://github.com/import-js/eslint-plugin-import/issues/2948
• https://github.com/eslint-community/eslint-plugin-promise/issues/449
• https://github.com/sindresorhus/eslint-plugin-unicorn/pull/2250
• https://github.com/typescript-eslint/typescript-eslint/issues/8211
• https://github.com/eslint/eslint/issues/18391
• https://github.com/vercel/next.js/issues/64409

[Walidoux]

Yesterday, I started migrating from v8.5.6 to v9.2.0 in another project, and it was a burden because of how much the Eslint's server, I guess, is no synced with the VSCode extension's version. I had to install the pre-release version, and yet I ran onto issues where .eslintrc files couldn't be found because Eslint has switched to flat configs: eslint.config.js, and this is where I realized that this wouldn't be possible, at least for for now, because a lot of plugins that currently use do not support the latest version of Eslint. I think we just have to wait for merge PRs.