The current answer is not a good solution for CJS and ESM in internal packages.

First of all my internal package cannot be distributed, assuming you have a @repo/utils that can be used by both react and nestjs.

1. if I compile the package, then the nestjs compilation won't include it, it won't exist at runtime.
2. if I use the Just-in-Time Packages package in the docs, it will be considered as an ESM and the CJS that nestjs requires will conflict with the typescript configuration.

There needs to be a way for nestjs, or any other webpack or vite or whatever, to include internal (non-published) packages in the build.

docs1: https://turbo.build/repo/docs/core-concepts/internal-packages#compilation-strategies
docs2: https://turbo.build/repo/docs/crafting-your-repository/creating-an-internal-package

There needs to be a way for nestjs, or any other webpack or vite or whatever, to include internal (non-published) packages in the build.

The documentation describes exactly this. Can you be more specific about the problem you're having?

I've tried a lot of methods that have solved my needs.

Current packaging tools do not support automatic handling of these internal packages for the time being (the Just-in-Time Packages approach to ESM and CJS coexistence), and should be documented to indicate that additional steps need to be configured.

Finally I need to configure the way all my apps are packaged

const nodeExternals = require('webpack-node-externals');

module.exports = (options, webpack) => {
  return {
    ...options,
    externals: [
      nodeExternals({
        allowlist: [/^@app/],
      }),
    ],
    devtool: 'source-map',
  };
};

My Solution.

1. all packages under packages are compiled with tsup for esm and cjs.
2. apps are forced to package dependencies starting with @app by configuring the compilation tool.

We do cover the general approach, but some tools may require additional steps or have their intricacies.

If you'd like to help us have information in the docs for your edge case, that'd be great! Happy to review your PR!