Unsupported css selector :is

[nestle49]

📝 Provide detailed reproduction steps (if any)

1. Include CKEditor 5 to vite/vue project
2. Build
3. Get warning after build - Unsupported css selector :is

✔️ Expected result

[wimleers]

Chrome 87 is ancient 😅 Is the target environment still correct?

[DaniilIsupov]

Chrome 87 is ancient 😅 Is the target environment still correct?

this is set by default https://vitejs.dev/config/build-options.html#build-target

https://github.com/vitejs/vite/blob/e0c86d4f210a302876fac280d9e79a2244e83b8b/packages/vite/src/node/constants.ts#L21

[Witoso]

This is most likely not related to the selector or build target but the usage of Vite. We release the CSS in packages that still requires processing (we plan to change it soon). Are you using our Vite plugin?

[nestle49]

Yes, I use vite plugin

[Witoso]

Could you check the setup from this comment: https://github.com/ckeditor/ckeditor5/issues/9807#issuecomment-1755980661, if it works we will update the docs.

[CKEditorBot]

There has been no activity on this issue for the past year. We've marked it as stale and will close it in 30 days. We understand it may still be relevant, so if you're interested in the solution, leave a comment or reaction under this issue.

[DaniilIsupov]

problem remains unresolved

[Witoso]

Could you provide a reproducible sample? The packages are now valid ESM, and those problems were not reported elsewhere, apart from a large Vite usage.

[nestle49]

Could you provide a reproducible sample? The packages are now valid ESM, and those problems were not reported elsewhere, apart from a large Vite usage.

https://github.com/nestle49/minimalReproductionCKEditor

1. Clone repo
2. npm i
3. npm run build

[Witoso]

Sorry for the late response. I cannot actually start this, for dev and build I get missing file src/assets/sprite/generated-sprite.svg. Could you resolve?

[nestle49]

Sorry for the late response. I cannot actually start this, for dev and build I get missing file src/assets/sprite/generated-sprite.svg. Could you resolve?

Fixed

[Witoso]

I unnecessarily went to the rabbit hole of our plugin being experimental, maybe something broke in Vite v5, etc., but no. This warning message is correct. We PostCSS our styles, and it rightfully mentions that :is will not be supported by the environments picked by Vite's defaults. Chrome 87 had :is as experimental AFAICS.

The solution to this issue for now is to bump the target, and set up a compatible environment. Later, this problem will be solved by #15502, and providing prebuilt stylesheets.