default_options.md

Default options for all selects

If you pass some options as defaults to all TreeType::class fields, you should create form type extension:

namespace Acme\DemoBundle\Form\Extension;

use Symfony\Component\Form\AbstractTypeExtension;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;
use Yavin\Symfony\Form\Type\TreeType;

class YTreeTypeExtension extends AbstractTypeExtension
{
    public function getExtendedType()
    {
        return TreeType::class;
    }

    public function setDefaultOptions(OptionsResolverInterface $resolver)
    {
        $resolver->setOptional([
            'treeLevelField' => 'lvl'
        ]);
    }
}

and add service:

<service class="Acme\DemoBundle\Form\Extension\YTreeTypeExtension">
    <tag name="form.type_extension" extended_type="Yavin\Symfony\Form\Type\TreeType"/>
</service>