fix: I18nContext.current() undefined when using additional interceptors

[lucas-gregoire]

Description

I discovered a bug when using disableMiddleware: true. When relying on I18nLanguageInterceptor to initialize the I18nContext, it's not possible to use another interceptor on the same endpoint. When doing so, the AsyncLocalStorage containing the i18n context is broken: I18nContext.current() always returns undefined.

How to reproduce

• Set disableMiddleware: true in I18nModule options.

• Define a simple interceptor such as:

  @Injectable()
  export class TestInterceptor implements NestInterceptor {
  intercept(_: ExecutionContext, next: CallHandler): Observable<unknown> {
  return next.handle();
  }
  }

• Add it on your endpoint:

  @Get()
  @UseInterceptors(TestInterceptor)
  helloWorld() {
  return I18nContext.current()?.lang;
  }

• This endpoint will always return undefined instead of the resolved lang. When removing the interceptor it works.

Additional context

I did something similar to the nestjs-cls's interceptor implementation: https://github.com/Papooch/nestjs-cls/blob/main/packages/core/src/lib/cls-initializers/cls.interceptor.ts I just simplified it by passing the observer directly to the subscribe method. I added a test in i18n-disable-middleware.e2e.spec.ts to avoid regressions.

See also:

• https://stackoverflow.com/questions/67136005/how-to-use-asynclocalstorage-for-an-observable

[coveralls]

coverage: 90.869% (+0.1%) from 90.764% when pulling 45d148d584357591d3103b867e501f82d05b378c on lucas-gregoire:fix/undefined-current-context into 0774e23b6e64fbfa7b5044e87c86e2b0f55fe7b7 on toonvanstrijp:main.