How to disable NestJS Logger, based on env?

Question

I'm using logger option in NestFactory.create() method to control Logger's log levels in production mode, but it's not working with ENV='production', still showing Logger.log() messages

const bootstrap = async () => {
  const app = await NestFactory.create<NestExpressApplication>(AppModule, {
    logger:
      env.ENV == 'development'
        ? ['debug', 'error', 'log', 'verbose', 'warn']
        : ['error', 'warn'],
  });

  app.enableCors();

  app.use(helmet());
  app.set('trust proxy', 1);

Answer 1

1. I create my custom logger
2. Inject it in the root module.

Within the constructor of the custom logger, that is where I put my condition using the setLogLevels function. I set the levels to empty, so it can ignore any console stdout.

import { ConsoleLogger, Injectable, LoggerService } from '@nestjs/common';

@Injectable()
export class AppLogger extends ConsoleLogger implements LoggerService {
  constructor(
    context: string,
    options?: {
      timestamp?: boolean;
    },
  ) {
    super(context, options);
    /***
     * @condition to check if it is in testing mode
     */
    if (condition) {
      this.setLogLevels([]);
    }
  }
}

Answer 2

Env variables are accessed with process.env global object, in Node.js.

The following example is working as expected, reading process.env.ENV:

async function bootstrap() {
  const app = await NestFactory.create(AppModule, {
    logger: process.env.ENV === 'production' ? ['warn', 'error'] : ['debug', 'log', 'verbose']
  });
  await app.listen(3000);
}

bootstrap();

yarn start display all initialization logs, whereas ENV=production yarn start shows no initialization logs.