Fix missing 'exports.types' field of package.json

[dalboris]

In a recent project set up with Vite+Typescript, I installed threejs-math (npm install threejs-math) and imported some types:

import { Vector2 } from "threejs-math";

But I got the following Typescript errors in my IDE (Sublime Text 4 with LSP-Typescript plugin):

There are types at `/home/boris/myproject/node_modules/threejs-math/types/index.d.ts`, but this result could not be resolved when respecting package.json "exports". The 'threejs-math' library may need to update its package.json or typings.

At first I thought it was probably a configuration problem of my project, my installation, or my IDE, but I couldn't fix it that way.

So following the suggestion of the error message, I looked online and found many projects having the same problem, which seems caused by the addition of new module resolution methods in recent versions of Typescript, see the following threads:

• Types that are found, but not exported in package.json, should still be usable microsoft/TypeScript#52363
• Add the types condition to the package.json#exports gxmari007/vite-plugin-eslint#60

The solution seems indeed to add the following to threejs-math/package.json :

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

I tested this change and indeed it makes the error message go away in my case, and all types are now properly imported in my project.

[dalboris]

Also see the following page, checking whether there's indeed something to be changed in threejs-math package.json:

https://arethetypeswrong.github.io/?p=threejs-math