Transforming data

Each property of a data object should be transformed into a usable type to communicate via JSON.

No complex transformations are required for the default types (string, bool, int, float and array), but special types like Carbon or a Laravel Model will need extra attention.

Transformers are simple classes that will convert a complex type to something simple like a string or int. For example, we can transform a Carbon object to 16-05-1994, 16-05-1994T00:00:00+00 or something completely different.

There are two ways you can define transformers: locally and globally.

##Local transformers

When you want to transform a specific property, you can use an attribute with the transformer you want to use:

class ArtistData extends Data{
    public function __construct(
        public string $name,
        #[WithTransformer(DateTimeInterfaceTransformer::class)]
        public Carbon $birth_date
    ) {
    }
}

The DateTimeInterfaceTransformer is shipped with the package and will transform objects of type Carbon, CarbonImmutable, DateTime and DateTimeImmutable to a string.

The format used for converting the date to string can be set in the data.php config file. It is also possible to manually define a format:

class ArtistData extends Data{
    public function __construct(
        public string $name,
        #[WithTransformer(DateTimeInterfaceTransformer::class, format: 'm-Y')]
        public Carbon $birth_date
    ) {
    }
}

Next to a DateTimeInterfaceTransformer the package also ships with an ArraybleTransformer that transforms an Arrayable object to an array.

It is possible to create transformers for your specific types. You can find more info here.

##Global transformers

Global transformers are defined in the data.php config file and are used when no local transformer for a property was added. By default, there are two transformers:

use Illuminate\Contracts\Support\Arrayable;
use Spatie\LaravelData\Transformers\ArrayableTransformer;
use Spatie\LaravelData\Transformers\DateTimeInterfaceTransformer;

/*
 * Global transformers will take complex types and transform them into simple
 * types.
 */
'transformers' => [
    DateTimeInterface::class => DateTimeInterfaceTransformer::class,
    Arrayable::class => ArrayableTransformer::class,
],

The package will look through these global transformers and tries to find a suitable transformer. You can define transformers for:

• a specific implementation (e.g. CarbonImmutable)
• an interface (e.g. DateTimeInterface)
• a base class (e.g. Enum)

##Getting a data object without transforming

It is possible to get an array representation of a data object without transforming the properties. This means Carbon objects won't be transformed into strings. And also, nested data objects and DataCollections won't be transformed into arrays. You can do this by calling the all method on a data object like this:

ArtistData::from($artist)->all();