auto-import with `package.json#imports` does not take `moduleResolution` into account

[alan910127]

🔎 Search Terms

"subpath", "imports", "package.json", "moduleResolution"

🕗 Version & Regression Information

• This changed in commit or PR Add auto-import for the package.json imports field #55015
• This is the behavior in every version I tried, and I reviewed the FAQ for entries about imports, completions

⏯ Playground Link

alan910127/ts-60405-repro

💻 Code

// package.json
{
  "imports": {
    "#*": "./src/*"
  },
  "devDependencies": {
    "typescript": "5.6.3"
  }
}

// tsconfig.json
{
  "compilerOptions": {
    "moduleResolution": "Bundler"
  }
}

// src/foo/bar/baz.ts
export function baz() {}

// src/one/two/three.ts
// actual   - import { baz } from "#foo/bar/baz.js";
// expected - import { baz } from "#foo/bar/baz";

🙁 Actual behavior

When auto-importing the function baz (either through completion or code action), the typescript language server will insert an import statement with a .js file extension.

import { baz } from "#foo/bar/baz.js";

🙂 Expected behavior

Since we are using "moduleResolution": "Bundler", it should insert an import statement without the .js file extension.

import { baz } from "#foo/bar/baz";

Additional information about the issue

I've seen a similar issue #59200, but I cannot reproduce the issue, with the same setup. Therefore, I think my issue might be related with the subpath imports.

[Andarist]

I don't think this is a bug. package.json#imports don't describe relative specifiers. Resolving #foo/bar/baz based on "#*": "./src/*" to ./src/foo/bar/baz.js would be incorrect.

A related comment to this by @andrewbranch :

#60003 (comment)

[alan910127]

Oh, I see. But TypeScript language server does not error if I use the extensionless module specifier either. Why is that the case?

[Andarist]

The thread I linked to specifically calls out extensionless module specifiers as erroring. If they are not then perhaps that is a bug - it might be good to wait for @andrewbranch to chime in. It would be good to understand the difference between that issue and yours.

[andrewbranch]

@alan910127 your repo link above 404s—did you accidentally make it private? If you share the repo, I’ll investigate. @Andarist is right; the import you listed as your expected behavior should have an error.

[leeyuky9802]

The thread I linked to specifically calls out extensionless module specifiers as erroring. If they are not then perhaps that is a bug - it might be good to wait for @andrewbranch to chime in. It would be good to understand the difference between that issue and yours.

Hi, I'm trying to implement a just in time ui lib in a monorepo. What do u think is the best practice now to implement absolute path resolve inside this pacakge? I'm currently using both package.json subpath import along with compilerOptions.path to surpress the warning. It works fine but I just really wanna keep the logic in one place :)