I’m trying to build a form where some has_one relations are optionnal.
Like in the case of has_many relations I want to display inputs_for fields only if the association already exists or if the user clic on a button to add the fields with some javascript.
Unfortunately when I use has_one relationship the fields are always present and I can’t hide them properly.
Is there a simple way to make them work as if the relation where defined as has_many?
Here is some code to illustrate the situation:
schema "people" do
....
has_one :phone_number, MyApp.People.PhoneNumber
...
end
def changeset(person, attrs) do
person
....
|> cast_assoc(:phone_number)
....
end
schema "phone_numbers" do
belongs_to :person, MyApp.People.Person
field :number, :integer
end
def new(conn, _params) do
...
changeset = People.Person.change_person(%Person{})
...
end
<%= form_for @changeset, @action, fn f -> %>
...... person fields .....
<%= inputs_for f, :phone_number, fn pn -> %>
<%= numner_input pn, :phone_number %>
<% end %>
<% end %>
If I convert the has_one to has_many it works but I feel like I’m not doing the right thing and I have to change a lot of thing elsewhere to reflect this “fake” has_many relationship.
I’ve try to encapsulate the inputs_for with things like:
if/unless @changeset.data.phone_number do ....
if/unless f.data.phone_number do ....
But this is not working properly.
What explains the difference of behavior of inputs_for with has_many and has_one ?
Any idea how to do it ?
