如何使用 TypeScript 在 package.json 上正确使用导出和子路径？

Question

It's my first time trying to create a npm package using TypeScript, and I've been experiencing some troubles, probably because I missunderstood something following the documentation. I'm using Node 16.16.0 with npm 8.13.2 at the moment of writing this.

First of all, my project structure looks like this.

src/
├─ module1/
│  ├─ index.ts
├─ module2/
│  ├─ index.ts
package.json
tsconfig.json

tsconfig.json

{
  "compilerOptions": {
    "target": "es2017",
    "module": "commonjs",
    "esModuleInterop": true,
    "declaration": true,
    "outDir": "./lib",
    "strict": true
  },
  "include": ["src"],
  "exclude": ["node_modules", "**/__tests__/*"]
}

package.json

{
  "name": "@owner/mypackage",
  "version": "v1.0.0",
  ...
  "files": [
    "lib/**/*"
  ],
  "type": "module",
  "exports": {
    "./module1": "./lib/module1/index.js",
    "./module2": "./lib/module2/index.js",
    "./package.json": "./package.json"
  }
}

The thing is that, when publishing the module, it generates the following structure:

lib/
├─ module1/
│  ├─ index.js
├─ module2/
│  ├─ index.js
package.json

Leaving me with the following importing structure:

import {Foo} from "@owner/mypackage/lib/module1";

Instead of the desired one:

import {Foo} from "@owner/mypackage/module1";

How can I achieve that pattern? And, in case there is, can I improve it or follow better practices?

Answer 1

Personally, in a project I have running Typescript 4.7+ , the following has worked: what you need is the typesVersions property in package.json instead. (see https://www.typescriptlang.org/docs/handbook/declaration-files/publishing.html#version-selection-with-typesversions )

I'll pull this quote out of the documentation above as relevance:

Well, if none of the fields in typesVersions get matched, TypeScript falls back to the types field , so here TypeScript 3.0 and earlier will be redirected to [...]/node_modules/package-name/index.d.ts.

Which essentially means, if the typesVersions field isn't defined in package.json , the types field is used, but the types field isn't helpful to us when when have multiple export paths with exports .

Hope this helps!

{
  "exports": {
    "./module1": "./lib/module1/index.js",
    "./module2": "./lib/module2/index.js",
  },
  "typesVersions": {
     "*": {
       "module1": ["lib/module1/index.js"],
       "module2": ["lib/module2/index.js"]
    }
  }
}