feat: support css esModule generator options

[ahabhgk]

What kind of change does this PR introduce?

feature, introduce esModule: false for css generator options

Did you add tests for your changes?

Added

Does this PR introduce a breaking change?

No

What needs to be documented once your changes are merged?

esModule css generator options

[webpack-bot]

For maintainers only:

• This needs to be documented (issue in webpack/webpack.js.org will be filed when merged)
• This needs to be backported to webpack 4 (issue will be created when merged)

[alexander-akait]

I think we can improve it in future PRs

[alexander-akait]

I don't think we really need the esModule option here, let's do it always, because we already return reasons in getConcatenationBailoutReason

[ahabhgk]

I don't think we really need the esModule option here, let's do it always, because we already return reasons in getConcatenationBailoutReason

Could you elaborate? Actually I didn't understand what you mean. Did you mean we don't need the generator.css.esModule: false options? or there is something we can improve in the PR?

[alexander-akait]

Sorry for delay, I mean we will work like esModule: true always, because it will allow to concate modules, I don't think somebody really needs esModule: false, what do you think?

[ahabhgk]

This is derived from an Rspack issue (sorry it is in Chinese), the component library in the user-imported node_modules uses the following code:

var _style = _interopRequireDefault(require("./style.less"));
function _interopRequireDefault(e) { return e && e.__esModule ? e : { "default": e }; }
_style["default"].foo;

Transformed by Babel from the following code:

import style from "./style.less";
style.foo;

So if __esModule is always true, _style["default"].foo will be undefined.

This case should be relatively rare because most packages on npm generally handle CSS Modules and Less themselves, rather than leaving it to users to handle as in this case. However, there are still some packages that do this, particularly those published on the company's intranet. (Some companies may have a unified framework that handles this on the user side instead of on the library side)

[alexander-akait]

@ahabhgk thank you, got it, let's remove console.log from test to avoid spam in console when we run tests

[webpack-bot]

@ahabhgk Thanks for your update.

I labeled the Pull Request so reviewers will review it again.

@alexander-akait Please review the new changes.