A very simple template to create NPM libraries with subpackages without worrying about it
Clone this repo
To generate a package
yarn create-package YOUR_PACKAGE
And you will have a subpackage created in the packages directory
To use the code from the main module you'll have to setup your tsconfig.json
When you build, this will run microbundle on all the subpackages and before publishing it will copy them to the root, so npm only sees your subpackage output
Your dependencies, peer dependencies will be handled for you
( Change the replace-me in your package.json and tsconfig.json to your library's name )