Symfony: many to many relation with text fields - forms

Question

We have a many to many relation with two entity Product {properties: name, details } and Tag {properties: name}. Now when a user add product, he must be able to create tags as well. So I tried this
$builder->add('tags', 'entity', array(
'class' => 'AppBundle:Tag',
'multiple' => true,
'expanded' => true,
'property' => 'name',
'required' => true
'allow_add' => true ));
Unfortunately, this gives me a drop down list of tags. But what I really want is multiple text input fields where user can enter the name of the tags and then this should save in the database when user save the category form.
All solutions I found so far are all related to either drop down or checkbox choices. But in my case, I don't have a list of tags in the database and I want to create the tags when user create a product. So how can I do that?

Answer 1

The entity type field could be only select, checkboxes or radio buttons (depending on expanded and multiple options), so these are not option for you.
You can solve multiple text fields rendering by implementing Tag type and embed it to your form as a collection.
Alter ProductType by collection field:
...
$builder->add('tags', CollectionType::class, array(
'allow_add' => true,
'allow_delete' => true,
'entry_type' => TagType::class,
'entry_options' => array(
...
),
)
...
Create TagType itself:
class TagType extends AbstractType
{
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder
->add('tagName', FormType\TextType::class);
}
public function configureOptions(OptionsResolver $resolver)
{
$resolver->setDefaults(array(
'data_class' => 'Entity\Tag',
)
);
}
}
But be aware of downsides - if there are not any tags assigned to the Product, the won't be any fields rendered. You have basically two options - 1) add few empty tags to the Product entity before rendering the form, 2) implement some kind of javascript method to add new tag fields.