The module, PolymorphicEmbed.HTML.Form appears to be entirely outdated for forms in Phoenix 1.7.2 and above. I needed PolymorphicEmbed.HTML.Form.get_polymorphic_type/3 to render the UI properly so I rewrote it:
def get_polymorphic_type(%Phoenix.HTML.Form{} = form, schema, field) do
module = PolymorphicEmbed.get_polymorphic_module(schema, field, form.params)
PolymorphicEmbed.get_polymorphic_type(schema, field, module)
end
At work we got stuck using the library to allow changing the type using a form. Is polymorphic_embed intended for this usecase? Or is the type meant to be chose once at creation time, and then stay fixed throughout its lifetime?
Edit: sorry, did not intend to make this a reply… it was meant to be a general question.
You just need to manipulate the type field in the polymorphic field (by default __type__).
So, given a “type” field (of type string) you could try something along this for example:
<.input field={@form[:type]} type="select" label="Select type" name={@form[:my_polymorphic_field].name <> "[__type__]"}
options={[{:sms, :sms}, {:email, :email}]} prompt="" />
I really love this and often faced the problem. The reason I haven’t found this before is the naming. Isn’t that more of a (algebraic) sum-type than polymorphism?
Big frameworks like Rails and Django calls the relational non-embedded versions “polymorphic associations” as does Ecto so that is likely what most people would be searching for.
This seems to work the first time I select something. But if I then change my selection, it doesn’t actually change anything. Even in my handle_event I’m not seeing the updated selection.