Validating dynamically loaded choices in Symfony 2

Question

I have a choice field type named *sub_choice* in my form whose choices will be dynamically loaded through AJAX depending on the selected value of the parent choice field, na

Answer 1

Adding an alternate approach for future readers since I had to do a lot of investigation to get my form working. Here is the breakdown:

1. Adding a "New" option to a dropdown via jquery
2. If "New" is selected display new form field "Custom Option"
3. Submit Form
4. Validate data
5. Save to database

jquery code for twig:

$(function(){
    $(document).ready(function() {
        $("[name*='[custom_option]']").parent().parent().hide(); // hide on load

        $("[name*='[options]']").append('New'); // add "New" option
        $("[name*='[options]']").trigger("chosen:updated");
    });

    $("[name*='[options]']").change(function() {
        var companyGroup = $("[name*='[options]']").val();

        if (companyGroup == 'new') { // when new option is selected display text box to enter custom option
            $("[name*='[custom_option]']").parent().parent().show();
        } else {
            $("[name*='[custom_option]']").parent().parent().hide();
        }
    });
});

// Here's my Symfony 2.6 form code:
    ->add('options', 'entity', [
    'class'         => 'Acme\TestBundle\Entity\Options',
    'property'      => 'display',
    'empty_value'   => 'Select an Option',
    'mapped'        => true,
    'property_path' => 'options.optionGroup',
    'required' => true,
])
->add('custom_option', 'text', [
    'required' => false,
    'mapped'   => false,
])

To handle the form data we need to use the PRE_SUBMIT form event.

    $builder->addEventListener(FormEvents::PRE_SUBMIT, function (FormEvent $event) {
    $data = $event->getData();
    $form = $event->getForm();
    if (isset($data['options']) && $data['options'] === 'new') {
        $customOption = $data['custom_option'];

        // todo: handle this better on your own
        if (empty($customOption)) {
            $form->addError(new FormError('Please provide a custom option'));
            return;
        }

        // Check for a duplicate option
        $matches = $this->doctrine->getRepository('Acme\TestBundle\Entity\Options')->matchByName([$customOption]);
        if (count($matches) > 0) {
            $form->addError(new FormError('Duplicate option found'));
            return;
        }

        // More validation can be added here

        // Creates new option in DB
        $newOption = $this->optionsService->createOption($customOption); // return object after persist and flush in service
        $data['options'] = $newOption->getOptionId();
        $event->setData($data);
    }
});

Let me know if ya'll have any questions or concerns. I know this might not be the best solution but it works. Thanks!