How can I return my generated authentication token from my NestJS Rest API initial Route to the Frontend using the Response Header

Question

How can I return my generated authentication token from my NestJS Rest API initial Route to the Frontend using the Response Header.

I have my AuthController that receives the request to validate the user and then return the Authentication token using Nest JWT. And for security reasons I want to return this Token in the Header of the response, but how can I return this value generated in my service to the response object?

@Get()
  async auth(
    @Req() req: Request)
  ) {
    const userData = await this.appService.login(req);
    userData.token?? // How to return this in the response header object?

    return userData;
  }