nextjs server crashes a esm package with type="module"

[jantimon]

Link to the code that reproduces this issue

https://github.com/jantimon/reproduction-webpack-import-module-bug/tree/nextjs

To Reproduce

1. clone the reproduction:
   git clone https://github.com/jantimon/reproduction-webpack-import-module-bug.git
2. switch to the nextjs branch
   git checkout nextjs
3. npm i
4. npm run dev

I am using the Webpack loader API this.importModule which invokes vm.runInThisContext to execute the module code.

However, as soon as the package.json file includes "type": "module" vm.runInThisContext does not have access to require and module anymore:

./banner.ts

import cowsay from "cowsay";

console.log(cowsay.say({
    text : "I'm a moooodule",
    e : "oO",
    T : "U "
}));

export const banner =  `;console.log("Build at ${new Date()}");\n`

loader.cjs

module.exports = function (source) {
    const callback = this.async();
    this.importModule('./banner.ts', {
        layer: "banner-loader"
    }, function (err, result) {
        callback(err, !err && (result?.banner || "") + source);
    });
}

next.config.mjs

/** @type {import('next').NextConfig} */
const nextConfig = {
    webpack: (config) => {
        config.module.rules.push({
                test: /\.tsx?$/,
                use: './loader.cjs',
                issuerLayer: (issuer) => issuer !== "banner-loader" ? issuer : "",
                exclude: /node_modules/,
        });
        return config;
    },
};
export default nextConfig;

next generates the following code: module.exports = require("cowsay"); which does not work in CSM and therefore breaks:

Current vs. Expected behavior

it would be nice if adding "type" = "module" when using the Webpack loader API this.importModule would not crash nextjs

Provide environment information

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 23.1.0: Mon Oct  9 21:27:24 PDT 2023; root:xnu-10002.41.9~6/RELEASE_ARM64_T6000
Binaries:
  Node: 20.9.0
  npm: 10.1.0
  Yarn: 1.22.19
  pnpm: 8.9.2
Relevant Packages:
  next: 14.1.0
  eslint-config-next: N/A
  react: 18.2.0
  react-dom: 18.2.0
  typescript: 5.3.3

Which area(s) are affected? (Select all that apply)

Not sure

Which stage(s) are affected? (Select all that apply)

next dev (local), next build (local)

Additional context

According to @alexander-akait it is not a webpack issue: webpack/webpack#18023

[VasiliyTelyatnikovTakeda]

I faced with a similar issue. We use internal UI library lives in the same monorepository when our Next.js application exist and connected via workspace:* feature. When we switched to "type": "module" in the library's package.json, which is our requirement to ship the UI library outside of the current monorepository, our Next.js application build has broken (but building itself has been done successfully).

Do we have some workaround for this issue? It completely brakes our websites.