exchange/app/Transformers/CategoryTransformer.php

<?php

namespace App\Transformers;

use League\Fractal\TransformerAbstract;

class CategoryTransformer extends TransformerAbstract
{
    private $locale;
    private $type;

    public function __construct($locale, $type)
    {
        $this->locale = $locale;
        $this->type = $type;
    }

    public function transform($category)
    {
        return $this->type == 'trading' ? [
            'id' => $category->id,
            'title' => $category->getTranslations('title', [$this->locale])[$this->locale] ?? '-',
        ] : [
            'id' => $category->id,
            'title' => $category->getTranslations('title', [$this->locale])[$this->locale] ?? '-',
            'type' => $category->type,
        ];
    }
}