feat(noUndeclaredVariables): add checkTypes option

[Conaclos]

Summary

See this thread for some context.

Add a new checkTypes option for noUndeclaredVariables.

The option is turned on by default. I plan to turn it off in Biome 2.0.
This will bring noUndeclaredVariables closer to no-undef (So we will set the rule as a source instead of an inspiration).
This also eliminates many false positives.
TypeScript is better suited to perform this kind of check.
We could consider in Biome 2.0 to turn on the rule by default because checkTypes set to false will reduce significantly the number of false positives.

I chose to name the option checkTypes instead of ignoreTypes because I plan to make it false by default.

Test Plan

I added a test.

[codspeed-hq]

CodSpeed Performance Report

Merging #4471 will improve performances by 6.1%

_{Comparing conaclos/noUndeclaredVariables-check-types (1addede) with main (3ad6da5)}

Summary

⚡ 1 improvements
✅ 98 untouched benchmarks

Benchmarks breakdown

	Benchmark	main	conaclos/noUndeclaredVariables-check-types	Change
⚡	react.production.min_3378072959512366797.js[uncached]	2.2 ms	2.1 ms	+6.1%

[arendjr]

We could consider in Biome 2.0 to turn on the rule by default

Maybe for 2.0 we can do a check in biome init to see if there is a tsconfig.json? If there is then we disable the rule since it would be redundant with TS, but if there isn’t we enable it.

It kinda makes me wonder if Biome 2.0 should even have the checkTypes option at all. If you use TypeScript, it takes care of it. If you don’t, you don’t have types anyway.

[ematipico]

It kinda makes me wonder if Biome 2.0 should even have the checkTypes option at all. If you use TypeScript, it takes care of it. If you don’t, you don’t have types anyway.

True, but people complain that TypeScript is slow. If Biome can do what TypeScript does already, but faster and without losing performance, I'd say it's a win for Biome :)

[arendjr]

If Biome can do what TypeScript does already, but faster and without losing performance, I'd say it's a win for Biome :)

I wholeheartedly agree, and it's a great argument for building our own type checker, but this option is not coming even near that 😅

[kurtextrem]

Thank you!

[elawad]

Hi, I tested the nightly build v1.9.5-nightly.81fdedb
But getting an error running Biome. Is the schema up to date, or did I miss something?

✖ options has an incorrect type, expected no value, but received an object.

  24 │         "noUndeclaredVariables": {
  25 │           "level": "error",
> 26 │           "options": { "checkTypes": false }
     │                      ^^^^^^^^^^^^^^^^^^^^^^^
  27 │         },

[Conaclos]

@elawad. I've just tested with the nightly and everything is ok for me. Please make sure you use the latest nightly (and check with npx @biomejs/biome --version. Otherwise, open an issue with a reproduction.

[elawad]

Thanks, please disregard. It was an error on my part. Needed to uninstall first, then install the nightly.