feat: add package.json exports for public packages

[bradzacher]

BREAKING CHANGE:
Restricts API surface by strictly defining package.json exports for each package

PR Checklist

• Addresses an existing open issue: fixes Use package.json exports to "hide" the dist folder for packages and control our exported surface-area #6050
• That issue was marked as accepting prs
• Steps in Contributing were taken

Overview

Configures option 3 from #6050 - where we completely lock down our API so people cannot access our dist folder any more.

Currently blocked on JoshuaKGoldberg/ts-api-utils#54

[typescript-eslint]

Thanks for the PR, @bradzacher!

typescript-eslint is a 100% community driven project, and we are incredibly grateful that you are contributing to that community.

The core maintainers work on this in their personal time, so please understand that it may not be possible for them to review your work immediately.

Thanks again!

---

🙏 Please, if you or your company is finding typescript-eslint valuable, help us sustain the project by sponsoring it transparently on https://opencollective.com/typescript-eslint.

[nx-cloud]

☁️ Nx Cloud Report

CI is running/has finished running commands for commit 00af53f. As they complete they will appear below. Click to see the status, the terminal output, and the build insights.

📂 See all runs for this branch

---

✅ Successfully ran 51 targets

• Node 18 - nx test eslint-plugin
• Node 14 - nx test eslint-plugin --coverage=false
• Node 18 - nx test typescript-estree
• Node 18 - nx test visitor-keys
• nx run-many --target=lint --parallel
• Node 18 - nx test scope-manager
• Node 18 - nx run-many --target=build --parallel --exclude website
• Node 18 - nx test utils
• Node 18 - nx test type-utils
• Node 18 - nx run-many --target=build --parallel --exclude website
• Node 18 - nx run-many --target=build --parallel --exclude website
• Node 18 - nx run-many --target=build --parallel --exclude website
• Node 18 - nx run-many --target=build --parallel --exclude website
• nx run-many --target=typecheck --parallel
• Node 14 - nx test typescript-estree --coverage=false
• Node 14 - nx test type-utils --coverage=false
• nx run-many --target=build --parallel --exclude website
• Node 14 - nx run-many --target=build --parallel --exclude website
• Node 14 - nx test parser --coverage=false
• Node 14 - nx test eslint-plugin-internal --coverage=false
• nx run integration-tests:test
• Node 14 - nx run-many --target=build --parallel --exclude website
• Node 14 - nx run-many --target=build --parallel --exclude website
• Node 14 - nx test scope-manager --coverage=false
• Node 18 - nx test eslint-plugin-tslint
• Node 14 - nx test eslint-plugin-tslint --coverage=false
• Node 14 - nx test ast-spec --coverage=false
• Node 14 - nx run-many --target=build --parallel --exclude website
• Node 14 - nx test visitor-keys --coverage=false
• Node 18 - nx run-many --target=build --parallel --exclude website
• Node 14 - nx test utils --coverage=false
• Node 14 - nx run-many --target=build --parallel --exclude website
• Node 18 - nx test ast-spec
• Node 14 - nx run-many --target=build --parallel --exclude website
• Node 18 - nx test parser
• Node 18 - nx test eslint-plugin-internal
• Node 14 - nx run-many --target=build --parallel --exclude website
• Node 14 - nx test repo-tools --coverage=false
• Node 14 - nx run-many --target=build --parallel --exclude website
• Node 14 - nx run-many --target=build --parallel --exclude website
• Node 14 - nx run-many --target=build --parallel --exclude website
• Node 14 - nx run-many --target=build --parallel --exclude website
• nx run-many --target=build --parallel --exclude website
• Node 18 - nx test repo-tools
• Node 18 - nx run-many --target=build --parallel --exclude website
• Node 18 - nx run-many --target=build --parallel --exclude website
• Node 18 - nx run-many --target=build --parallel --exclude website
• Node 18 - nx run-many --target=build --parallel --exclude website
• nx run-many --target=build --parallel --exclude website
• Node 18 - nx run-many --target=build --parallel --exclude website
• nx run-many --target=build --parallel --exclude website

---

Sent with 💌 from NxCloud.

[codecov]

Codecov Report

Merging #6458 (00af53f) into v6 (fc2df63) will increase coverage by 0.00%.
The diff coverage is 100.00%.

Additional details and impacted files

@@           Coverage Diff           @@
##               v6    #6458   +/-   ##
=======================================
  Coverage   87.05%   87.06%           
=======================================
  Files         365      365           
  Lines       12580    12579    -1     
  Branches     3720     3720           
=======================================
  Hits        10952    10952           
  Misses       1278     1278           
+ Partials      350      349    -1     

Flag	Coverage Δ
unittest	87.06% <100.00%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
.../eslint-plugin/src/rules/prefer-ts-expect-error.ts	100.00% <ø> (ø)
...lugin-internal/src/rules/plugin-test-formatting.ts	79.76% <100.00%> (ø)
packages/eslint-plugin/src/util/astUtils.ts	88.88% <100.00%> (ø)
...s/eslint-plugin/src/util/collectUnusedVariables.ts	93.16% <100.00%> (-0.03%)	⬇️
...s/utils/src/eslint-utils/rule-tester/RuleTester.ts	70.23% <100.00%> (ø)
packages/eslint-plugin/src/rules/no-mixed-enums.ts	95.83% <0.00%> (+1.38%)	⬆️

[bradzacher]

Hmm.. I can't reproduce the typecheck failure locally... There's no reason it shouldn't work considering it's not the ESM version of the package.

Maybe there's an issue with the CI getting the wrong version? Idk why it would be different to local considering it's covered by the yarn.lock

[JoshuaKGoldberg]

Glorious, I love it. 👏

Left some suggestions inline but they're all nice-to-haves IMO.

[JoshuaKGoldberg]

Should be fixed in JoshuaKGoldberg/ts-api-utils#37 -> ts-api-utils@0.0.22.

[bradzacher]

I guess the issue now is that TS won't let us import this file because it sees type: 'module' and our project is type: 'commonjs'

[JoshuaKGoldberg]

We could switch to type: 'module' 😈

[bradzacher]

Yup - we can't import the package without this patch.
TS looks at type: module and treats it as an exclusively esm package, erroring:

src/convert-comments.ts:1:24 - error TS1479: The current file is a CommonJS module whose imports will produce 'require' calls; however, the referenced file is an ECMAScript module and cannot be imported with 'require'. Consider writing a dynamic 'import("ts-api-utils")' call instead.
  To convert this file to an ECMAScript module, change its file extension to '.mts' or create a local package.json file with `{ "type": "module" }`.
       
1 import * as tools from 'ts-api-utils';
                          ~~~~~~~~~~~~~~

So we'll need to keep this patch (in perpetuity?)
Maybe this needs to be changed in the package so it doesn't list type?

[JoshuaKGoldberg]

Hmm, I suppose we could take an issue in ts-api-utils. But I do wonder what the actual blockers to typescript-eslint going ESM are.

[bradzacher]

I do wonder what the actual blockers to typescript-eslint going ESM are.

In order for CJS to load ESM, it must use an import() expression.

ESLlint is CJS and does not use import() to load plugins - it uses require (via createRequire [1])
https://github.com/eslint/eslintrc/blob/main/lib/config-array-factory.js#L1086
https://github.com/eslint/eslintrc/blob/main/lib/config-array-factory.js#L984

So we need to export a CJS API from our packages. Now we could get around that and use ESM with a CJS facade in front of an ESM package and leverage import() expressions to load the ESM "backend", however our plugin and parser need to have fully synchronous APIs to adhere to the ESLint requirements.

Because the plugin needs to be CJS, all our lint utilities (utils, type-utils, scope-manager, etc) need to be CJS.
Because the parser needs to be CJS, all our parser utilities (visitor-keys, typescript-estree, etc) need to be CJS.

So for now we're firmly stuck as a project shipping CJS :(