select2 on nested forms with rails

Question

I figured out, that throughout the generation of the nested form divs, i don't know how to get a default value there.

Within the normal form, it looks like following

<%= f.hidden_field :toolkeeper, :id => "toolkeeper_value" %>
<%= f.select :toolkeeper,  options_from_collection_for_select(@people, :id, :name), :include_blank => true, :selected => '25' %>

and the corresponing JS:

$ ->
  $("#practice_toolkeeper")
    .select2({ 
         allowClear: true,
         placeholder: 'Select an item'
    })
    .select2('val',$("#toolkeeper_value").val())

but within the generation of the nested forms, the hidden_field #ID which I use to get the existing value for the selector changes like :

select#practice_uebung_maps_attributes_1_role_id
select#practice_uebung_maps_attributes_2_role_id
...

what is the correct way to write a JS-Script, which initializes the .select2() and also takes the hidden_field value?

Answer 1

Ok i've finally figured it out with some help of my friends:

i've added a function, to create select2 forms:

  function build_select2_role(counter){
    $("#practice_uebung_maps_attributes_"+counter+"_role_id").select2({
      allowClear: true,
      placeholder: 'Rolle'
    }).select2('val',$("#role_id_"+counter).val())
  };

and in the fields_for section, i only call this function (filled by a local variable):

<% @runs = 0 %>
<td>
  <%= map.hidden_field :role_id, :id => "role_id_#{@runs}"  %>
  <%= map.select :role_id,  options_from_collection_for_select(@roles, :id, :name), :include_blank => true %></td>
  <script type='text/javascript'> 
      build_select2_role(<%= @runs %>);
  </script>
</td>
<% @runs += 1 %>