🐛 Bug: Properly dual-export CJS and ESM

[JoshuaKGoldberg]

Bug Report Checklist

• I have tried restarting my IDE and the issue persists.
• I have pulled the latest main branch of the repository.
• I have searched for related issues and found none that matched my issue.

Expected

I thought I'd set up dual-exporting CJS and ESM files properly in 6bf5c33, based on https://github.com/JoshuaKGoldberg/create-typescript-app/blob/c6714eeb02a5106eb5e4e4694f1e8b590444030d/docs/FAQs.md#how-can-i-add-dual-commonjs--ecmascript-modules-emit.

Actual

https://github.com/JoshuaKGoldberg/eslint-plugin-package-json/actions/runs/12854886842/job/35839775194?pr=750 shows an error:

Run node ./lib/index.js
/home/runner/work/eslint-plugin-package-json/eslint-plugin-package-json/node_modules/.pnpm/[email protected]_@[email protected].[6](https://github.com/JoshuaKGoldberg/eslint-plugin-package-json/actions/runs/12854886842/job/35839775194?pr=750#step:5:7)[email protected][email protected]_/node_modules/eslint-fix-utils/lib/index.cjs:18
__reExport(index_exports, require("./fixRemoveArrayElement.js"), module.exports);
                          ^

Error [ERR_REQUIRE_ESM]: require() of ES Module /home/runner/work/eslint-plugin-package-json/eslint-plugin-package-json/node_modules/.pnpm/[email protected]_@[email protected][email protected][email protected]_/node_modules/eslint-fix-utils/lib/fixRemoveArrayElement.js from /home/runner/work/eslint-plugin-package-json/eslint-plugin-package-json/node_modules/.pnpm/[email protected]_@[email protected][email protected][email protected]_/node_modules/eslint-fix-utils/lib/index.cjs not supported.
Instead change the require of fixRemoveArrayElement.js in /home/runner/work/eslint-plugin-package-json/eslint-plugin-package-json/node_modules/.pnpm/[email protected]_@[email protected][email protected][email protected]_/node_modules/eslint-fix-utils/lib/index.cjs to a dynamic import() which is available in all CommonJS modules.
    at Object.<anonymous> (/home/runner/work/eslint-plugin-package-json/eslint-plugin-package-json/node_modules/.pnpm/[email protected]_@[email protected][email protected][email protected]_/node_modules/eslint-fix-utils/lib/index.cjs:18:2[7](https://github.com/JoshuaKGoldberg/eslint-plugin-package-json/actions/runs/12854886842/job/35839775194?pr=750#step:5:8))
    at Object.<anonymous> (/home/runner/work/eslint-plugin-package-json/eslint-plugin-package-json/lib/rules/no-redundant-files.js:24:31)
    at Object.<anonymous> (/home/runner/work/eslint-plugin-package-json/eslint-plugin-package-json/lib/plugin.js:26:33)
    at Object.<anonymous> (/home/runner/work/eslint-plugin-package-json/eslint-plugin-package-json/lib/index.js:26:21) {
  code: 'ERR_REQUIRE_ESM'
}

Additional Info

Interestingly, that PR's test job passes. So it's not seemingly a blocker to using this package as an end-user. Just the CI of an implementing ESLint plugin.

💖

[michaelfaith]

I believe it's that main is pointing to the esm entry point. There should be a module that points to the esm entry point, and main points to the cjs entry point. I can take a look at it later, if you don't get to it sooner.

[michaelfaith]

oh! And I think this is also a result of the issue I mentioned in the PJV TS PR. Having .js explicitly in the import like that, is going to cause the .cjs files to try and require the esm versions of the files they import (which have the .js extension). I think there are a few ways we could deal with that. Like changing tsup to bundle, instead. If tsup supported rewriteRelativeImportExtensions (egoist/tsup#1271), it would make things a whole lot easier on us.

[JoshuaKGoldberg]

@all-contributors please add @JoshuaKGoldberg for bug.

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[allcontributors]

@JoshuaKGoldberg

I've put up a pull request to add @JoshuaKGoldberg! 🎉