At what point does a Carbon object turn to string in Laravel?

Question

Looking to write a cast similar to Carbon dates with Laravel, I realized that a Carbon date is converted to a string when passed over to the front-end or blade component.

I have been digging the source code with no luck, does anybody know how this works?

My understanding is that the __toString() method is called on the carbon object at some point but don't know where.

an example would be:

$user = User::first();
// here created_at is a Carbon instance

return response()->with(['created_at' => $user->created_at]);
//once this is on blade created_at is a string

Answer 1

So after more digging found out that json_encode() is responsible for this.

Therefore if you a json_encode a carbon object, the output is a string. The responses are converted to JSON in laravel's ResponseFactory.

If you would like to pass a PHP object through a response and would like to only receive a string instead of an object you can utilize JsonSerializable

class MyClass implements JsonSerializable
{
 public function jsonSerialize(): string
 {
   return 'something';
 }
}

$class = new MyClass()
json_encode($class) // "'something'"

Hope this helps someone in the future