TypeScript 6.0 CSS import issues | TypeScript Community | Page 1

dense karma Mar 31, 2026, 8:56 PM

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I am getting this error when trying to import CSS:

src/components/Ketcher/KetcherDialog.tsx:1:8 - error TS2882: Cannot find module or type declarations for side-effect import of 'ketcher-react/dist/index.css'.

1 import "ketcher-react/dist/index.css";
         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This only started happening when I upgrade to TS 6.0. I would like to align with 7.0 defaults if possible, and adding ketcher-react to compilerOptions.types doesn't silence the error. What is the solution here?

dense summit Mar 31, 2026, 9:59 PM

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https://devblogs.microsoft.com/typescript/announcing-typescript-6-0/#:~:text=noUncheckedSideEffectImports is now true by default%3A This helps catch issues with typos in side-effect-only imports.

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either declare that these imports work via declare module "*.css" (vite prepopulates this for you!), or set noUncheckedSideEffectImports: false

dense karma Apr 1, 2026, 8:49 AM

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dense summit either declare that these imports work via `declare module "*.css"` (vite prepop...

unfortunately I'm stuck on webpack so I'll do the former

karmic knoll Apr 1, 2026, 2:41 PM

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I think there's a webpack-env entry you can add to your types array

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... but then I don't remember if it actually includes stuff like css types.

#TypeScript 6.0 CSS import issues