Lots of work here, mostly because I didn't want to turn off the
`noImplicitAnyLet` lint. This PR tries its best to type all the untyped
lets biome complained about (Don't ask me how many hours that took or
how many lints that was >200...), which in the future will force test
authors to actually type their global variables setup in `beforeAll`.
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Co-authored-by: Gastón Fournier <gaston@getunleash.io>
This commit changes our linter/formatter to biome (https://biomejs.dev/)
Causing our prehook to run almost instantly, and our "yarn lint" task to
run in sub 100ms.
Some trade-offs:
* Biome isn't quite as well established as ESLint
* Are we ready to install a different vscode plugin (the biome plugin)
instead of the prettier plugin
The configuration set for biome also has a set of recommended rules,
this is turned on by default, in order to get to something that was
mergeable I have turned off a couple the rules we seemed to violate the
most, that we also explicitly told eslint to ignore.
