How is use-baseline intended to work with tools like PostCSS? Or is it, even?

[benjaminblack]

It seems like the goals of linting CSS with @eslint/css with the use-baseline rule, and transforming CSS with PostCSS + postcss-preset-env, are at cross purposes.

For example, use-baseline will flag the & nesting selector as not widely available, but when using PostCSS, nesting syntax is fine (and almost expected), since it will be transformed.

And yet, @eslint/css provides for custom configuration via customSyntax which is expressly called out in the docs as useful for working with PostCSS, which suggests that perhaps they are intended to work together.

[nzakas]

use-baseline has no relationship to PostCSS. Syntax allowed by PostCSS may or may not be baseline, and not being in baseline doesn't necessarily mean you shouldn't use it, just that you should double-check your target browsers to ensure it's working properly.

And yet, @eslint/css provides for custom configuration via customSyntax which is expressly called out in the docs as useful for working with PostCSS, which suggests that perhaps they are intended to work together.

The customSyntax section does not mention PostCSS at all. The tolerant section mentions setting it to true if you are using custom syntax provided by a PostCSS plugin.

[benjaminblack]

The customSyntax section does not mention PostCSS at all. The tolerant section mentions setting it to true if you are using custom syntax provided by a PostCSS plugin.

The "Configuring Custom Syntax" doc section is immediately preceded by this sentence, so you can forgive me for thinking that the intention is to describe how to use customSyntax to support PostCSS at-rules.

Setting tolerant to true is necessary if you are using custom syntax, such as PostCSS plugins, that aren't part of the standard CSS syntax.

Configuring Custom Syntax

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