Support ESLint 8.x

[MichaelDeBoey]

💻

• Would you like to work on this feature?

What problem are you trying to solve?

ESLint v8.0.0 is released 🎉

It would be awesome to have official ESLint 8 support. 👊
I'm happy to help where I can of course 🙂

Describe the solution you'd like

All ESLint packages support ESLint 8.x

Describe alternatives you've considered

/

Documentation, Adoption, Migration Strategy

No response

[babel-bot]

Hey @MichaelDeBoey! We really appreciate you taking the time to report an issue. The collaborators on this project attempt to help as many people as possible, but we're a limited number of volunteers, so it's possible this won't be addressed swiftly.

If you need any help, or just have general Babel or JavaScript questions, we have a vibrant Slack community that typically always has someone willing to help. You can sign-up here for an invite."

[nicolo-ribaudo]

@MichaelDeBoey I looked at the migration guide and it seems like we might be able to support it with minimal changes, but it's impossible to know without actually trying. I would love a PR for it! It would be ideal to support both ESLint 7 and ESLint 8 at the same time, to give an easy migration path.

Since you ticked the "Would you like to work on this feature?" box I'm assigning this to you. If you need any help or if you don't want to work on this, please leave a comment!

If it is the first time that you contribute to Babel, follow these steps: (you need to have make and yarn available on your machine)

1. Write a comment here to let other possible contributors know that you are working on this bug.
2. Fork the repo
3. Run git clone https://github.com/<YOUR_USERNAME>/babel.git && cd babel
4. Run yarn && make bootstrap
5. Wait ⏳
6. Run make watch (or make build whenever you change a file)
7. Update the code!
8. yarn jest eslint to run the tests
9. If it is working, run make test to run all the tests
10. Run git push and open a PR!

[JLHwung]

Note that we will need to enable the classFeatures for ESLint 8:

babel/eslint/babel-eslint-parser/src/worker/configuration.cjs

Line 11 in d5b0d9e

// todo: enable classFeatures when it is supported by ESLint

If we want to support both ESLint 7 and ESLint 8, we will need to read the eslint version and use different options for them.

[nicolo-ribaudo]

@MichaelDeBoey Are you interested in opening a PR for this? If not, I can work on it this week.

[gajus]

I believe the work for this is already being done here

#13782

[ljharb]

Thanks, eslint-plugin-react will still have to actually start testing with the new parser, but we're definitely blocked on that PR.

[JLHwung]

@ljharb You can actually start testing new parser now:

module.exports = {
  parser: "@babel/eslint-parser",
  parserOptions: {
    requireConfigFile: false,
    babelOptions: {
      parserOpts: {
        plugins: [
          ["estree", { classFeatures: true }],
        ],
      },
    },
  },
};

In Babel 7.16 we materialize the classFeatures option but AFAIK the AST shape does not change.

[ljharb]

@JLHwung i'm working on it :-) but a bunch of tests are failing, since eslint-plugin-react has never tested on the scoped parser before.

(edit: sorry, i got confused about which repo i was commenting on)