sarga/packages/Webkul/API/Http/Resources/Catalog/AttributeGroup.php

<?php

namespace Webkul\API\Http\Resources\Catalog;

use Illuminate\Http\Resources\Json\JsonResource;

class AttributeGroup extends JsonResource
{
    /**
     * Transform the resource into an array.
     *
     * @param  \Illuminate\Http\Request
     * @return array
     */
    public function toArray($request)
    {
        return [
            'id'          => $this->id,
            'code'        => $this->code,
            'name'        => $this->name,
            'swatch_type' => $this->swatch_type,
            'attributes'  => Attribute::collection($this->custom_attributes)
        ];
    }
}