class weatherForecasterService{  
  constructor(options) {
    this.options = options ?? {
      appendAmountOfRainToForecast: false
    }
  }
  generateWeatherForecast(location) {
    let forecast = buildForecast(location);
    if(this.options.appendAmountOfRainToForecast) {
      forecast = appendAmountOfRain(forecast)
    }
    return forecast;
  }
}

class featureAwareWeatherForecasterServiceFactory{
  build() {
    const options = {
      appendAmountOfRainToForecast: featureDecisions.appendAmountOfRainToForecast()
    }
    
    return new weatherForecasterService(options);
  }
}

const weatherForecaster = new featureAwareWeatherForecasterServiceFactory().build();