feat: support flat config

[hyoban]

PR Checklist

• Addresses an existing open issue: fixes 🚀 Feature: Support flat config #91
• That issue was marked as status: accepting prs
• Steps in CONTRIBUTING.md were taken

Overview

Some code are not very good, looking forward to your suggestions

[codecov]

Codecov Report

Attention: Patch coverage is 98.48485% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 99.22%. Comparing base (8d9ed75) to head (591f08f).
Report is 94 commits behind head on main.

Files	Patch %	Lines
src/plugin.ts	97.72%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #161      +/-   ##
==========================================
- Coverage   99.30%   99.22%   -0.08%     
==========================================
  Files          15       17       +2     
  Lines         866      907      +41     
  Branches       73       74       +1     
==========================================
+ Hits          860      900      +40     
- Misses          6        7       +1     

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[JoshuaKGoldberg]

Ok! So sorry for taking multiple weeks to get back to you on this - it's a good change and important for the plugin. Thank you very much for getting it started!

The general path you took here seems reasonable to me. Glad to see the actual changes to src/index.ts are pretty straightforward. I left some requests inline about streamlining how the dual-emit (CJS/ESM) and dual-format (flat/legacy) support should look.

Also, per #91 (comment), requesting:

Document how to use them with flat config in the README.md

I think I'd made a note to get back to this PR once that was in and forgot to follow up 😅.

[hyoban]

Hi, I have changed the code to apply your suggestion. I intentionally left the documentation section until the implementation is refined based on your review, which has now been added.

Thanks a lot for your review. I have learned a lot.

[JoshuaKGoldberg]

This looks great, thanks a bunch @hyoban! 🙌

I only have some small, honestly non-blocking comments left. Do you have opinions on them?

If not, no worries, I've set a reminder to merge this on Wednesday. 🚀

[hyoban]

@JoshuaKGoldberg I have no problem with your modification, but I don't have a computer with me now. You can modify and merge it directly. Or I will deal with it tomorrow.

[JoshuaKGoldberg]

You got it, I'll go ahead and do that now so we can release today. Thanks!

[JoshuaKGoldberg]

Figured I'd add a quick one here so code coverage doesn't drop. 🤷

[github-actions]

🎉 This is included in version v0.11.0 🎉

The release is available on:

• GitHub releases
• npm package (@latest dist-tag)

Cheers! 📦🚀