[package.json] exposes types to npm

[Ayc0]

Description

Fixes #32

Changes

As described in https://www.typescriptlang.org/docs/handbook/esm-node.html, we need to expose types in 2 fields:

• top level, for CJS fall-back for older versions of Node.js
• in the exports field, as entry-point for TypeScript resolution - must occur first!

// package.json
{
    "name": "my-package",
    "type": "module",
    "exports": {
        ".": {
            // Entry-point for TypeScript resolution - must occur first!
            "types": "./types/index.d.ts",
            // Entry-point for `import "my-package"` in ESM
            "import": "./esm/index.js",
            // Entry-point for `require("my-package") in CJS
            "require": "./commonjs/index.cjs",
        },
    },
    // CJS fall-back for older versions of Node.js
    "main": "./commonjs/index.cjs",
    // Fall-back for older versions of TypeScript
    "types": "./types/index.d.ts"
}

[LeaVerou]

Thanks!