Add "types" field to package.json "exports"

[futurGH]

In TypeScript 4.7, the nodenext and node16 module resolution options were added to better support native ESM in Node.js. When the package.json "exports" field exists, however, they require a "types" field to exist within each entrypoint, or else types won't be resolved when using one of these module resolution options.

Currently, using this library with either of those settings throws the following TypeScript error:

error TS7016: Could not find a declaration file for module '@splinetool/react-spline'. '/project-path/node_modules/@splinetool/react-spline/dist/react-spline.cjs.js' implicitly has an 'any' type.
  Try `npm i --save-dev @types/splinetool__react-spline` if it exists or add a new declaration (.d.ts) file containing `declare module '@splinetool/react-spline';

This PR fixes this issue by adding the "types" field to "exports" for the "./" entrypoint. The same change is required for @splinetool/runtime, but I couldn't find a link to a repository where I could submit the change.

[marcofugaro]

Hey @futurGH, could you share your setup? I've just tried using react-spline with Typescript 4.8.2 via create-react-app and it worked no problem. Repro.

Shouldn't it fallback to the root "types" field in package.json?

[futurGH]

Thanks for looking into this @marcofugaro. You can find a better explanation of this issue than I'm capable of at microsoft/TypeScript#46334. Essentially, the top-level "types" field only applies when importing from "main". When you compile to native ESM and use "nodenext" or "node16" for TS' module resolution, it instead defaults to the "." import map, which requires its own "types" field, as TS won't look up the top-level "types" field if it's not looking at the "main" field as the entrypoint.

[marcofugaro]

Right, thanks for linking to the conversation.

[futurGH]

Thanks for merging this! I'd also appreciate if a similar change could be made to the @splinetool/runtime package; I don't believe the source for the package is public for me to submit a PR to?

[marcofugaro]

@futurGH a new version of @splinetool/runtime with this fix will be published early next week