Cast array fields to JSON when saving in upsert model

[mauriciodinamarca]

Hello!
We used spatie/data-transfer-object package before, and we had an easy way to transform array properties to JSON with a transformer (or caster I think), but with spatie-data I couldn't find a better way to cast to JSON before saving. As an example, here's a Data object using Microsoft graph api (omitted all parameters for brevity):

<?php
/**
 * @see https://learn.microsoft.com/en-us/graph/api/resources/event?view=graph-rest-1.0
 */
class EventData extends Data
{
    public function __construct(
        ...
        public array|null $categories
        public array|null $onlineMeeting
    ) {}
}

We make a call using another package (saloon) and it returns the laravel-data DTO object. Before saving with upsert, I need to transform the fields to json, something like this:

$dtoAsArray = Arr::map($dtoCollection, callback: function ($element) {
foreach (['categories', 'onlineMeeting'] as $key) {
                $element = $element->toArray();
                $element[$key] = array_key_exists($key, $element) ? json_encode($element[$key]) : null;
                return $element;
            }
}

Is there a better way when transforming to array those fields get transformed to JSON?
I couldn't find (read this and also looked in Github discussions)
Thanks in advance!
Best,