Because of this issue https://github.com/nestjs/nest/issues/882#issuecomment-1046242517
the guard doesnt work on handleConnection. The comments have some examples and there is one that worked for me:

export type SocketMiddleware = (socket: Socket, next: (err?: Error) => void) => void;
export const WSAuthMiddleware = (jwtService: JwtService, configService: ConfigService, knex: Knex, logger: Logger): SocketMiddleware => {
  return async (socket, next) => {
    try {
      const token = socket?.handshake?.auth?.token;

      if (!token) {
        throw 'Missing token';
      }

      const decodedToken = await validateToken(token, jwtService, configService);

      next();
    } catch (error) {
      logger.error(`${error}`);
      next({
        name: 'unauthorized',
        message: `${error}`,
      });
    }
  };
};

async function validateToken(token: string, jwtService: JwtService, configService: ConfigService): Promise<IToken> {
  const jwtSecret = configService.get('jwtSecret');
  const decodedToken = await jwtService.verifyAsync(token, { secret: jwtSecret });

  if (!decodedToken) {
    throw 'Invalid token';
  }

  return decodedToken;
}

events.gateway.ts

async afterInit() {
    const middle = WSAuthMiddleware(this.jwtService, this.configService, this.knex, this.logger);
    this.io.use(middle);
    this.logger.log('Initialized');
}

When I pass token null or bad format jwt, the client is not receiving the error, it only receives if i kill the server.
I logged the socket.disconnected, which is true all time.
In nestjs, how do I make it work to client side to receive error event lifecyle?