[ybiquitous]

Which issue, if any, is this issue related to?

Closes #6258
Ref #5291

Is there anything in the PR that needs further explanation?

This Pull Request is necessary for Conditional exports (ESM and CJS).

Note: For backward compatibility, we may need to export stylelint/lib/utils/* files.
The following script can easily output many lib/utils/ settings.

Script

import path from 'node:path';

import fg from 'fast-glob';

const exports = {
	'.': {
		import: './lib/index.mjs',
		require: './lib/index.cjs',
	},
	'./package.json': './package.json',
};

const files = fg.sync('lib/utils/isStandardSyntax*.mjs', { ignore: '**/__tests__/**' });

for (const file of files) {
	const base = path.basename(file, '.mjs');
	exports[`./lib/utils/${base}`] = {
		import: `./lib/utils/${base}.mjs`,
		require: `./lib/utils/${base}.cjs`,
	};
}

console.log(JSON.stringify(exports, null, 2));

I'd like to hear feedback about exporting lib/** files. Should we export all files? I worry about frequent breaking changes in the future, if we exposed all modules (including internal ones).

Ideally, we should export utilities only through stylelint.utils, but actually we don't. Especially, isStandardSyntax* utilities are necessary to write a plugin or a custom rule.