Add ESLint rule to prevent usage of the order CSS property

[afercia]

Description

See #61241

Some components come with CSS in JS.

#61241 and #61243 aim to introduce a stylelint rule to prevent usage of the order CSS property, which is impactful for accessibility.

In the same way, it would be nice to add an ESLint rule to prevent usage of the order CSS property in any *.js file.

Unfortunately this isn't exactly my area of expertise so that I'd appreciate some guidance. I did see a similar rule added in #58130

Step-by-step reproduction instructions

• Add an order CSS property e.g. order: 1; to any CSS-in-JS for example in this file..
• Run npm run lint:js.
• Observe the linter does not report any error.

Screenshots, screen recording, code snippet

No response

Environment info

No response

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

Yes

[afercia]

I guess the patterns to catch would be, at least, the following ones. With and without leading spaces or tab characters:

order: 123;
    order: 123;

order: 123,
    order: 123,

order: '123',
    order: '123',


'order: 123;'
    'order: 123;'

[ghostp13409]

Hey, I'm fairly new to open-source and web development, but I would love to give it a try

[afercia]

@ghostp13409 welcome. Sure, please do feel free to work on a Pull Request.

I did try to follow a previous example that added another ESLint rule, see #59022. But I'm not good at regular expressions. Also, I have no idea how that works. I did try to go through the ESLint custom rules docs and the docs for selectors but this isn't really my area of expertise. Wondering if there's any simpler way to detect the order CSS property in JS. @mirka any help would be appreciated, when you have a chance 🙇🏽‍♂️

It gets complicated because of the several ways CSS can be coded in JS. It could be a key/value pair within an object, or a string, or a concatenated string... etc.

Note the JS linter can be run in the terminal with this command: npm run lint:js -- --quiet

[mirka]

CSS-in-JS can either be done with strings or objects. The string case can be caught similar to #59022 without much downside, but the object case will be trickier because { order: 3 } is something that could validly appear in code unrelated to styling.

I wouldn't say this rule is particularly necessary at the moment, given that:

• We currently have zero violations in @wordpress/components code, and we generally have more rigorous reviews on CSS that gets merged in the package. (CSS-in-JS is only used in @wordpress/components)
• There will be increasingly fewer usages of CSS-in-JS as we migrate off of Emotion.

Might be fine to revisit once we actually encounter an order slipping through.