Laravel Api Resources

I'm having problems understanding API resources in laravel 5.8. Supose I have a model called "Bars", and an API resource called BarResource:

class BarResource extends JsonResource
{
    public function toArray($request)
        return [
            'id' => $this->id,
            'name' => $this->name, 
        ]
    }
}

Ok. That works fine. Now I need to pass to every call, if the bar is opened or not (I can easeily calculate that). Where should I put the function that check if the bar is opened or closed?

class BarResource extends JsonResource
{
    public function toArray($request)
    {
        return [
            'id' => $this->id,
            'name' => $this->name, 
            'is_opened' => ??????
        ]
    }
}

Thanks a lot!