Trying to build an association for a has_many from a multiple_select.
While examining the log, I noticed that input_for stores every child under "0"
key in a map.
In my case, this is what I have in template
<div>
<%= label fp, :languages %>
<%= multiple_select fp, :value, Enum.map(@languages, fn x -> {x.id, x.value} end) %>
</div>
<% end %>
This is what I see when inspecting struct going to :create
%{"languages" => %{"0" => %{"value" => ["3"]}}}
Any additional form result inside the input_for is put inside the map under the key “0”.
My question is what is so special about this “0”? Where is it coming from?