Laravel add additional array of dates while model retrieving

I have relationship between User and Attendance, where in Attendance table I have field start and end which are date fields. I'm able to retrieve the data through relationship. I'm getting User Absences for current month and afterwards I want to add "additional" field/variable/attribute with array of this dates(parsed to Carbon) to User model. Is it possible?

I was trying to use booted() method with static::retrieved function, where I call another.

When I need to check those absences in view to display a Calendar I iterate too many times (previously I've created a method inside Users model to retrieve and parse those data).

I need to achieve something like this:

if(in_array($someDates, $user->additional_array)) [...]

Previously I've got:

if(in_array($someDates, $user->methodToReturnAdditionalArray())) [...]

Any idea?

You can use the Laravel Attributes and define the new method for getting the data you want

Example:

public function getAdditionalArrayAttribute()
{
    // return the list of array items you want;
}

And then you can use it like here:

$model->additional_array;