Does not work with CSS-modules

[akhdefault]

Here's repro:
https://github.com/akhdefault/eslint-classnames-repro/blob/main/pages/index.js#L10

[fsubal]

What is the expected behavior in this case? ( Not sure from the comment in your repo )

You mean className={classNames(styles.main)} should be fixed into className={styles.main} ?

[fsubal]

It is actually prevented here → https://github.com/fsubal/eslint-plugin-classnames/blob/main/lib/rules/prefer-classnames-function.js#L95-L115

Dropping classNames() function for single argument is problematic when it's not a string literal value.
This is why it's currently prevented.

className={classNames({ a: true })}
className={{ a: true }} // This is wrong, of course

className={classNames(foo ? 'a' : 'b')}
className={foo ? 'a' : 'b'} // This can be acceptable, but not expected?

Maybe you can add some cases for specially allowing single argument with Identifier expression ?

[akd-io]

Took a look at this today @fsubal, and ended up realizing exactly what you wrote here; that it's problematic without a literal string value.

I guess you would need to use typescript-eslint's type checking to check that classes.myClass in classNames(classes.myClass) is of type string before allowing it to collapse from

className={classNames(classes.myClass)}

into

className={classes.myClass}

But that's a significantly bigger task, and should be its own rule as type-aware linting performs slower.