Avoid N+1 queries in API resources

You can avoid N+1 queries in API resources by using the whenLoaded() method.

This will only append the department if it’s already loaded in the Employee model.

Without whenLoaded() there is always a query for the department

 1class EmplyeeResource extends JsonResource
 2{
 3    public function toArray($request): array
 4    {
 5        return [
 6            'id' => $this->uuid,
 7            'fullName' => $this->full_name,
 8            'email' => $this->email,
 9            'jobTitle' => $this->job_title,
10            'department' => DepartmentResource::make($this->whenLoaded('department')),
11        ];
12    }
13}

Tip given by @mmartin_joo