Expected Behavior

Hi, I am working on transitionning Meteor packages to NPM.

In Meteor, you have the possibility to create full-stack packages quite easily, by creating client and server package.
This behaviour is surprisingly hard to reproduce with bare NPM packages structured in a Lerna repo and built with Webpack.

My dream setup:
Files would be like this:

client/index.ts
server/index.ts
index.ts
package.json

Then imports are like this:

import { serverOnly } from "my-fullstack-package/server"

I have 2 or 3 build steps: one for shared code, one for client-only code, one for server-only code.

Current Behavior

First difficulty: at the time of writing TypeScript doesn't support multiple entry points in NPM packages, so you have to use an hackish solution with typings (see https://stackoverflow.com/questions/63058081/package-json-with-multiple-entrypoints).
But that's not really related to Lerna so let's ignore this.

My package.json looks like this:

{
  "name": "@vulcanjs/mongo",
  "main": "./dist/index.js",
  "files": [
    "dist/"
  ],
  "exports": {
    ".": "./dist/index.js",
    "./client": "./dist/client/index.js"
  },
  "types": "./dist/index.d.ts",
  "typesVersions": {
    "*": {
      "client": [
        "./dist/client/index.d.ts"
      ]
    }
  },

It works ok, I can import client-only code from downstream apps correctly.

Second difficulty: when I mistakenly import a relative path of a local package, I end up with multiple folders in my build.

Like import foobar from "other-package/foobar" will get the following result in the build of my-package:

dist/other-package
dist/my-package

Instead of having directly:

dist/index.js # from my-package

This seems to be an expected behaviour, usually I solve this by removing all those "local" imports and fixing my exports.
However, my problem is that I also have this behaviour when importing one of my entry points, like other-package/client. This time, client is not a nested file, but an actual entry point.

Possible Solution

First, having better explanation about what happens when mixing Lerna and Webpack. Maybe the issue is easy to fix, but I fail to find documentation in the wild. It's not very clear what happens/what is supposed to happen in those scenarios.

I seem to be able to trick Webpack by creating a fake, wrong alias for the external package with multiple entry points => it will prevent it to try to build the external package.

resolve: {
    alias: {
       "other-package/server": "not_found" // doesn't seem to affect the build, Webpack simply ignore the package
   }
}

{
  "version": "0.4.0",
  "npmClient": "yarn",
  "useWorkspaces": true,
  "packages": [
    "packages/*"
  ],
  "command": {
    "publish": {
      "ignoreChanges": [
        "*.md"
      ]
    }
  }
}

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Context

I have a (non-minimal) open source setup: https://github.com/VulcanJS/vulcan-npm

Your Environment