FR: Add javascript.exported config, as a counterpart to javascript.globals

[chrisgrieser]

biome currently has an allowlist for noUndeclaredVariables in the form of javascript.globals, where we can globally define exceptions for noUndeclaredVariables instead of disabling the rule at every occurrence of the variable.

I'd like to propose introducing javascript.exported which should act as an allowlist for noUnusedVariables in the very same way. Other tools like for example the lua LSP allow for such an allowlist. eslint also supports such an allowlist, but in the form of the rule option for no-unused-vars.

The use case of such a setting / rule option would be to allow for variables that are implicitly exported, for example the run function in JXA. (Right now, the alternative is to literally add a disabling-comment at every single occurrence of such run functions.)

[Conaclos]

Could you add an example? or link to an example?

Why not explicitly export the variable?

[chrisgrieser]

Why not explicitly export the variable?

JXA does not support any sort of export/import statements (it basically always runs in single-file-mode). run is a special variable, if running a JXA file, the run function is automatically called, even if you have no run() statement in your code.

Could you add an example? or link to an example?

Given a file foobar.js with the following content, osascript l- JavaScript "foobar.js" will return hello world:

function run() {
  console.log("hello  world")
}

[ematipico]

I'm not really sure what JXA is, but globals wasn't only meant for rules, but for other tools such as transformer and/or minifier.

If we want to add an exception, it should be inside the rule