Creating a Transformer

Build custom transformers to convert complex values into simple types

Transformers take complex values and transform them into simple types. For example, a Carbon object could be transformed to 16-05-1994T00:00:00+00.

Transformer Interface

Implement the Transformer interface:

interface Transformer
{
    public function transform(DataProperty $property, mixed $value, TransformationContext $context): mixed;
}

Parameters

• property - DataProperty object representing the property being transformed (read more)
• value - The value to transform (never null)
• context - TransformationContext containing:
  • transformValues - Whether values should be transformed
  • mapPropertyNames - Whether property names should be mapped
  • wrapExecutionType - The execution type for wrapping values
  • transformers - Collection of available transformers

Return Value

Return the transformed value.

Example Transformer

use Spatie\LaravelData\Transformers\Transformer;
use Spatie\LaravelData\Support\DataProperty;
use Spatie\LaravelData\Support\Transformation\TransformationContext;

class DateTimeTransformer implements Transformer
{
    public function transform(DataProperty $property, mixed $value, TransformationContext $context): string
    {
        return $value->format('Y-m-d H:i:s');
    }
}

Use in your data class:

use Spatie\LaravelData\Attributes\WithTransformer;

class SongData extends Data
{
    public function __construct(
        public string $title,
        #[WithTransformer(DateTimeTransformer::class)]
        public DateTime $releasedAt,
    ) {
    }
}

Combining Transformers and Casts

Create a class that both transforms and casts:

class ToUpperCastAndTransformer implements Cast, Transformer
{
    public function cast(DataProperty $property, mixed $value, array $properties, CreationContext $context): string
    {
        return strtoupper($value);
    }
    
    public function transform(DataProperty $property, mixed $value, TransformationContext $context): string
    {
        return strtoupper($value);
    }
}

Use with the WithCastAndTransformer attribute:

class SongData extends Data
{
    public function __construct(
        public string $title,
        #[WithCastAndTransformer(ToUpperCastAndTransformer::class)]
        public string $artist,
    ) {
    }
}