fix: add types

[unional]

Add types to the package.

TypeScript need this to read the type definition.

btw, the ESM one likely using module: Node16 should be the correct value, instead of ESNext.

But that can be a different PR.

[isaacs]

Huh, I have no reason to object to this, but I'm curious why it doesn't pull in types for you just by virtue of them being in the same folder as the module being loaded. I see them getting pulled in with typescript 4.9.3, what version are you using?

[isaacs]

btw, the ESM one likely using module: Node16 should be the correct value, instead of ESNext.

The ESM build usings tsconfig-esm.json, which has:

{
  "extends": "./tsconfig-base.json",
  "compilerOptions": {
    "module": "esnext",
    "outDir": "dist/mjs"
  }
}

So yeah, it's using esnext. If it was using node16, it wouldn't produce esm modules.

[unional]

Um, interesting. It is possible that it is improved in some newer versions of TypeScript. It was needed for many versions and I help a lot of packages to add the type definitions, including my own.

Also for ESM, when I start converting my packages to dual modules a few months ago, I definitely notice they are needed, especially for subpath exports.

e.g. the following didn't work when consuming as ESM when I tried it:

{
  "exports": {
    "." : { /* no "types" field */ }
  },
  "main": "...",
  "types": "..."
}

If it works without those fields, feel free to remove them. Less is more. 🍻

[isaacs]

It is possible that it is improved in some newer versions of TypeScript. It was needed for many versions and I help a lot of packages to add the type definitions, including my own.

That's my guess. No real harm in having it there, if it makes some older versions of TypeScript work properly, then that's good enough reason to keep it.

I am noticing that the same exact .d.ts files get duplicated using my hybrid setup, I wonder if there's a way to have one of them reference the other. Tricky when there's more than one module exported, though.

[unional]

I am noticing that the same exact .d.ts files get duplicated using my hybrid setup, I wonder if there's a way to have one of them reference the other. Tricky when there's more than one module exported, though.

There are two ways to do it:

1. set declaration to false in tsconfig for CJS
2. Use package.json files glob

Nowadays I use the second approach in my packages because I want to make sure everything are compiled correctly, including tests.

Adding !/dist/cjs/**/*.d.ts there will fix the issue.

UPDATE: actually, don't do that. I'm working on a demo that you may need both:
https://github.com/cyberuni/typescript-module-resolutions-demo

[unional]

@isaacs 👆 pls ignore what I said about removing one set of declaration.