Description
Describe the feature you'd like:
I am a maintainer of storybook-builder-vite, which allows storybook users to build their previews using vite, which works entirely in ESM. Storybook recently also released @storybook/jest and the latest release extends expect with jest-dom matchers. However, since jest-dom is only published as commonjs, typescript needs to add a compatibility layer so that import * as matchers from @testing-library/jest-dom/matchers; can be used. This is causing an issue, whereby a default is being included as well, causing expect to throw an error. See storybookjs/jest#15 (comment) for the error description.
To avoid the esm/cjs bundling problems, I'd like to request that jest-dom publish an esm version alongside cjs.
Suggested implementation:
I see that you're using kcd-scripts build, which also allows a --bundle flag that builds cjs, esm, umd, and umd.min bundles. Alternatively, https://github.com/unjs/unbuild is a very simple build tool which can generate multiple targets.
Describe alternatives you've considered:
I'm trying to troubleshoot the symptom of the esm->cjs namespace import to see if there's a way I can work around it in the storybook packages, but I think it would be nice if this package could publish esm anyway, especially now that jest itself is publishing es modules.
Teachability, Documentation, Adoption, Migration Strategy:
I think as long as the package.json is updated correctly, there shouldn't be any user-facing changes needed. That said, bundling the files as suggested above will cause problems if users are importing files directly from node_modules/@testing-library/jest-dom/dist. If that's the case, and it's a use case that needs to be supported, then a different build process will be needed, but can still be accomplished.