[BUG] Non-ASCII whitespace should not be treated as class separator

[uhyo]

Describe the bug
It is a common mistake among Japanese developers to mistakenly insert an Ideographic Space (U+3000) in place of a normal space character (U+0020).
Example:

<div className="px-1　py-2">notice that the space between px-1 and py-2 is a U+3000</div>

According to the relevant spec, px-1[U+3000]py-2 is treated as one class name, not two separated by the space. Only ASCII whitespaces are treated as separators. Therefore, px-1[U+3000]py-2 is not recognized as a Tailwind class by browsers and it does not have any effect. I would like this plugin to catch this kind of mistake.

However, eslint-plugin-tailwindcss considers px-1[U+3000]py-2 as two classes (px-1 and py-2) so it cannot catch this mistake.

To Reproduce
Steps to reproduce the behavior:

1. Enable the no-custom-classname rule
2. Run the rule against <div className="px-1　py-2">notice that the space between px-1 and py-2 is a U+3000</div>
3. Currently you get no error.

Expected behavior
The no-custom-classname rule should complain that px-1　py-2 is not a valid Tailwind classname.

Screenshots

Environment (please complete the following information):

• OS: macOS
• Softwares + version used:
  • tailwind@3.3.2
  • eslint-plugin-tailwindcss@3.12.0

Additional context

• prettier-plugin-tailwindcss seems to have the same issue.
  • Do not split classes by non-ASCII whitespace tailwindlabs/prettier-plugin-tailwindcss#166

eslint config file or live demo

[francoismassart]

Available for testing and feeback via npm i eslint-plugin-tailwindcss@3.12.1-beta.0