====

Use a custom Eloquent cast to transform a JSON column into a rich PHP Value Object—this gives you encapsulation, immutability and type safety throughout your app. For example:

1. Create your Value Object:

```php
final class Address
{
    public function __construct(
        public string $street,
        public string $city,
        public string $zip
    ) {}
}
```

2. Create a CastsAttributes class:

```php
use Illuminate\Contracts\Database\Eloquent\CastsAttributes;

class AddressCast implements CastsAttributes
{
    public function get($model, string $key, $value, array $attributes): Address
    {
        $data = json_decode($value, true) ?? [];
        return new Address($data['street'] ?? '', $data['city'] ?? '', $data['zip'] ?? '');
    }

    public function set($model, string $key, $value, array $attributes): array
    {
        if ($value instanceof Address) {
            $payload = [
                'street' => $value->street,
                'city'   => $value->city,
                'zip'    => $value->zip,
            ];
        } elseif (is_array($value)) {
            $payload = $value;
        } else {
            throw new InvalidArgumentException('Invalid address format.');
        }

        return [$key => json_encode($payload)];
    }
}
```

3. Register the cast in your model:

```php
class User extends Model
{
    protected $casts = [
        'address' => AddressCast::class,
    ];
}
```

Now whenever you access `$user->address`, you get an `Address` object; when you assign one, it’s automatically serialized back to JSON.