Core: Add CJS entrypoints to errors in core events

[yannbf]

Closes #24009

What I did

When running tests with composeStories in Jest where node with ESM is not enabled, the tests fail with:

This PR solves that.

Checklist for Contributors

Testing

The changes in this PR are covered in the following automated tests:

• stories
• unit tests
• integration tests
• end-to-end tests

Manual testing

Use this repro:

• https://github.com/lukemcd-hero/storybook-test
• change a typo in Button.test.js in that repo:

- const { Default } = composeStories(stories)
+ const { Primary } = composeStories(stories)

• Update to the canary 0.0.0-pr-24038-sha-abd016e1
• npm run test – it should work

Documentation

• Add or update documentation reflecting your changes
• If you are deprecating/removing a feature, make sure to update
  MIGRATION.MD

Checklist for Maintainers

• When this PR is ready for testing, make sure to add ci:normal, ci:merged or ci:daily GH label to it to run a specific set of sandboxes. The particular set of sandboxes can be found in code/lib/cli/src/sandbox-templates.ts

• Make sure this PR contains one of the labels below:

  Available labels

  • bug: Internal changes that fixes incorrect behavior.
  • maintenance: User-facing maintenance tasks.
  • dependencies: Upgrading (sometimes downgrading) dependencies.
  • build: Internal-facing build tooling & test updates. Will not show up in release changelog.
  • cleanup: Minor cleanup style change. Will not show up in release changelog.
  • documentation: Documentation only changes. Will not show up in release changelog.
  • feature request: Introducing a new feature.
  • BREAKING CHANGE: Changes that break compatibility in some way with current major version.
  • other: Changes that don't fit in the above categories.

🦋 Canary release

This pull request has been released as version 0.0.0-pr-24038-sha-abd016e1. Install it by pinning all your Storybook dependencies to that version.

More information

Published version	0.0.0-pr-24038-sha-abd016e1
Triggered by	@yannbf
Repository	storybookjs/storybook
Branch	yann/fix-cjs-entries-on-core-events
Commit	abd016e1
Datetime	Sun Sep 3 19:48:50 UTC 2023 (1693770530)
Workflow run	6066425997

To request a new release of this pull request, mention the @storybookjs/core team.

core team members can create a new canary release here or locally with gh workflow run --repo storybookjs/storybook canary-release-pr.yml --field pr=24038

[IanVS]

Are you sure this is a cjs issue? I notice that the error message includes ".js" on the end of the file, which we don't include in our export map. Or, does jest just not respect / understand export maps.

[shilman]

Any idea why this isn't handled by the export map? E.g.

https://github.com/storybookjs/storybook/blob/next/code/lib/core-events/package.json#L38C5-L38C5

[yannbf]

Are you sure this is a cjs issue? I notice that the error message includes ".js" on the end of the file, which we don't include in our export map. Or, does jest just not respect / understand export maps.

Any idea why this isn't handled by the export map? E.g.

I thought maybe the exports maps were an ESM only thing, but it might as well be an issue with Jest. I'm not entirely sure!

[IanVS]

@SimenB, sorry for the ping, but I was wondering if Jest does not support export maps in package.json. This PR feels a little like a hack, and I was wondering if you knew of any better ways to add support for Jest in this case.

[IanVS]

@yannbf do you know where the ".js" on the file name came from? Is that something in our code, or did it get added somewhere (maybe by jest itself)?

[yannbf]

@yannbf do you know where the ".js" on the file name came from? Is that something in our code, or did it get added somewhere (maybe by jest itself)?

Alright I did a proper investigation and here's what's going on.
I believe most, if not all of the projects from #24009 use Jest 27, either from outdated dependencies or because of react-scripts. The issue happens in jest-resolve at this line: https://github.com/jestjs/jest/blob/main/packages/jest-resolve/src/resolver.ts#L351

This issue does not happen in Jest 29. jest-resolve v29 is able to resolve a package correctly based on its exports map.

Therefore, this PR is a workaround to maintain compatibility with jest 27 projects, and because we support CRA, it's important.

cc @shilman

[SimenB]

Yeah, Jest has full support from v29 (partial support (. only) in v28)