tsconfig paths and package.json#exports doesn't work together

[yusufkandemir]

🔎 Search Terms

• paths aliases exports
• paths package.json#exports
• paths node_modules

🕗 Version & Regression Information

• This is the behavior in every version I tried: ~5.4, ~5.5, ~5.6, 5.7.0-beta, 5.7.1-rc, and 5.8.0-dev.20241108

⏯ Playground Link

https://stackblitz.com/edit/ts-paths-and-exports-bug?file=ts-app/tsconfig.json&file=ts-app/1-broken-with-alias.ts&file=ts-app/1-broken-with-alias.ts&view=editor

💻 Code

js-package/package.json:

"exports": {
  "./wrappers": {
    "types": "./lib/app-wrappers.d.ts",
    "import": "./lib/app-wrappers.js"
  }
}

ts-app/0-working-without-alias.ts:

import { defineConfig } from 'js-package/wrappers';

ts-app/1-broken-with-alias.ts:

import { defineConfig } from '#pkg/wrappers';

ts-app/tsconfig.json:

{
  "compilerOptions": {
    // Use an option that respects package.json#exports
    "module": "Preserve", // or NodeNext (both behaves the same in this example)

    "paths": {
      "#pkg": ["node_modules/js-package"]
    }
  }
}

🙁 Actual behavior

TypeScript can't resolve #pkg/wrappers and fails. Adding an alias through paths doesn't respect package.json#exports.

Side case: the same happens with just #pkg, so it's not just about subpaths. Unless you provide package.json#types, it doesn't work. So, it doesn't respect something like this either:

"exports": {
  ".": {
    "types": "lib/index.d.ts"
  }
}

🙂 Expected behavior

I expect tsconfig paths and package.json#exports to work together. TS respects package.json#exports everywhere else fine, so it should also be working fine when using paths too.

Additional information about the issue

A workaround is to define a paths entry that mimics the exports entry, for every entry point needed. Example:

"paths": {
  "#pkg/wrappers": ["node_modules/js-package/lib/app-wrappers.d.ts"],

  "#pkg": ["node_modules/js-package/lib/index.d.ts"], // or just `node_modules/js-package` and define `package.json#types = lib/index.d.ts`

  "#pkg/other-exports": ["node_modules/js-package/lib/foo.d.ts"],
  "#pkg/yet-another": ["node_modules/js-package/lib/bar/baz.d.ts"],
}