`--disallow-code-generation-from-strings` breaks nest's named ESM exports

[ephys]

Is there an existing issue for this?

• I have searched the existing issues

Current behavior

If you run node with the --disallow-code-generation-from-strings option & use native ESM imports, some named ESM imports break.

Minimum reproduction code

https://github.com/ephys/nest-esm-issue

Steps to reproduce

1. npm ci
2. node index.mjs # should run without issues
3. node --disallow-code-generation-from-strings index.mjs # should break: named import not found

Expected behavior

For named exports to be available even when --disallow-code-generation-from-strings is used

Package

I've only tested the first 4 packages of this list, only @nestjs/core succeeded (but it's possible one of the imports is failing. This issue is likely relevant to all packages):

• I don't know. Or some 3rd-party package
• @nestjs/common
• @nestjs/core
• @nestjs/microservices
• @nestjs/platform-express
• @nestjs/platform-fastify
• @nestjs/platform-socket.io
• @nestjs/platform-ws
• @nestjs/testing
• @nestjs/websockets
• Other (see below)

Other package

No response

NestJS version

9.2.1

Packages versions

"@nestjs/core": "^9.2.1",
"@nestjs/common": "^9.2.1",
"@nestjs/microservices": "^9.2.1",
"@nestjs/platform-express": "^9.2.1",

Node.js version

18.13.0

In which operating systems have you tested?

• macOS
• Windows
• Linux

Other

I think this can be fixed by including an ESM export map file, like I've done in other projects here: https://github.com/sequelize/sequelize/blob/main/src/decorators/legacy/index.mjs (+ test to ensure it stays up to date)

[jmcdo29]

We haven't set up ESM support yet, so anything that is working is not by design and anything that isn't working is not a bug. When we make Nest compatible with ESM this will be resolved. In the meantime, I followed the errors from the output and wrote the import { Logger } ... as

import pkg from '@nestjs/common'
const { Logger } = pkg

and your code worked. Annoying, sure, but it works

[4-1-8]

Wouldn't it be useful to keep it open so it can be added as tests later when Nest will support ESM modules?