Scoped module type definition files are not resolved

[bentruyman]

TypeScript Version: 2.2.2

Code

// tsconfig.json
{
  "compilerOptions": {
    "module": "commonjs",
    "outDir": "dist",
    "target": "es5",
    "typeRoots": ["types"]
  },
  "include": ["src/**/*"]
}

// src/index.ts
import * as scoped from "@scope/scoped";

scoped("str");

// node_modules/@scope/scoped
module.exports = function (str) {
    return str;
}

// types/@scope/scoped/index.d.ts
declare module "@scope/scoped" {
    interface Scoped {
        (str: string): string;
    }

    const scoped: Scoped;

    export = scoped;
}

Expected behavior:

Running tsc should successfully compile the project into the dist directory.

Actual behavior:

A compile error is printed:

error TS2688: Cannot find type definition file for '@scope'.

Comments:

This is because it appears the compiler is only looking in the top-level directory (in this case, types/@scope) for a type definition and not the directory of the scoped package (types/@scope/scoped). A few projects in the DefinitelyTyped project have gotten around this limitation by employing some variations of the same technique[1][2][3].

Here's what I've seen as workarounds:

• Publish an entire scope's module definitions under a single file @scope/* => scope (downloading more than necessary)
• Publish a scoped module as un-scoped @scope/module => module (collisions possible?)
• Use a special naming convention @scope/module => scope__module

In this project, the issue can be fixed if one just moves types/@scope/scoped to types/scoped.

Maybe this is something that just needs to be handled in conventions used by the folks in the DefinitelyTyped project (e.g. @scope/module => scope__module). But what this issue is proposing is a solution that is likely to be the expected experience when doing the above. This is maybe less of a bug and more of a developer ergonomics/UX issue.

I'd be perfectly cool closing this issue and just recommending documentation changes be made to call out this case and suggest the third bullet item above as a solution. This use case is especially useful for those of us individuals or companies with a semi-large catalog of scoped private packages and are making the migration to Typescript.

I have a PR out for your third option there. #15051

[blakeembrey]

See also: microsoft/types-publisher#155.

[mhegazy]

Should be addressed by #15051