Using the export keyword between a decorator and a class is not allowed. Please use export @dec class instead.

[geersch]

Describe the bug

We are using Vitest to run tests for a NestJS application which relies on legacy decorators. SWC is used to do the transpilation. After updating from version 1.7.28 to 1.7.35 tests started failing.

Input code

NestJS provider.

@Injectable()
export class MyService { }

Test suite.

import { MyService } from './MyService.js';

describe('MyService', () => {
  it('should test something', async () => {
    const service = new MyService();
    ...
  });
});

Config

Using the unplugin-swc plugin for Vitest to configure SWC.

import swc from 'unplugin-swc';

const vitestConfig = {
  test: { ... },
  plugins: [
    ...,
    swc.vite({
       module: { type: 'es6' },
    }),
  ]
}

Playground link (or link to the minimal reproduction)

https://play.swc.rs/?version=1.7.35&code=H4sIAAAAAAAAA0srzUsuyczPU%2FDMy0pNLklMyknVSM7PKy4pKk0uyS%2ByUnCDKtBUqObiquXickBSqMmVnJNYXKzgWxmcWlSWmZwKVgMAKWCzZFMAAAA%3D&config=H4sIAAAAAAAAA22RzU7DQAyE7zxFtOKImoIEh94QVSUO8A5m47Rb9k%2B2IxpVeXecn0ah9GjPtzMe7fmuKMw92wMGMJvCHEQyb8qSf%2ByKuByF1ZFTNA89GlLVeFTyrJPO0uZ%2BMsgvRjfdAB3ZLgigPcrIPK0fnwcf3WcgRpo53XAbBU492buyJZdlolWt0CYCScRKCDU4Ky7kRPLKaicuxYs%2ByN2UJgSR60RhGehxD7bdXoyvfefEDxSoQOAaaBi3WLuIu0RvHph3Dn11M%2F8bMQ%2FIJwT828DgKSO5gNreL8%2Fr37yP3UTIfTWC%2F7pjcFNzveEGXIPn6ZL5e4KLrm5nsfsF2uTyGAQCAAA%3D

SWC Info output

Operating System:
    Platform: darwin
    Arch: arm64
    Machine Type: arm64
    Version: Darwin Kernel Version 24.0.0: Tue Sep 24 23:39:07 PDT 2024; root:xnu-11215.1.12~1/RELEASE_ARM64_T6000
    CPU: (10 cores)
        Models: Apple M1 Pro

Binaries:
    Node: 20.17.0
    npm: 10.8.2
    Yarn: 4.4.0
    pnpm: 8.15.5

Relevant Packages:
    @swc/core: 1.7.35
    @swc/helpers: N/A
    @swc/types: 0.1.13
    typescript: 5.6.2

SWC Config:
    output: N/A
    .swcrc path: N/A

Next.js info:
    output: N/A

Expected behavior

The compiled output should not break. Same as version 1.7.26.

Actual behavior

Either we get the error Using the export keyword between a decorator and a class is not allowed. Please use export @dec class instead. or SyntaxError: Invalid or unexpected token.

Version

1.7.35

Additional context

No response

[kdy1]

Can you try changing the target to something other than esnext? I think this is #9640 but I can't be sure as there's no repro.

[geersch]

Yes, looks to be related. In another project which doesn't target ESM version 1.7.35 does not cause these issues.

[boan-anbo]

Same error, same set up (NestJS + swc + Vitest). Targeting ES2022 instead of ESNext works OK for now, but not ES2023.

[geersch]

Version 1.7.36 resolves the issue for me. Thanks!

[swc-bot]

This closed issue has been automatically locked because it had no new activity for a month. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.