[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:

• Support eslint v9 import-js/eslint-plugin-import#2948
• Support ESLint 9 and Flat config eslint-community/eslint-plugin-promise#449
• Update ESLint to v9, drop support for Node.js v16 sindresorhus/eslint-plugin-unicorn#2250
• ESLint v9 Support typescript-eslint/typescript-eslint#8211
• 📈 Tracking: ESLint v9 support eslint/eslint#18391

[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.