Rails nested_form adding items to table rows

Question

My goal is to use the nested_form gem: https://github.com/ryanb/nested_form but instead of creating just a new set of labels and fields every time you add an object, I wanted to insert a row into an existing table.

= nested_form_for @transaction do |f|
%h3 Line Items 
%table
  %tr
    %th Branch
    %th Department
    %th Invoice #
    %th Amount
    %th Transaction Type
    %th Deposit (y/n)
    %th

  = f.fields_for :line_items do |line_item|
    %tr
      %td 
        = line_item.text_field :location_id
      %td 
        = line_item.text_field :department_id
      %td 
        = line_item.text_field :invoice_num
      %td 
        = line_item.text_field :amount
      %td 
        = line_item.text_field :transaction_type
      %td 
        = line_item.text_field :deposit
      %td= line_item.link_to_remove "Remove"
    %p= f.link_to_add "Add", :line_items

The .link_to_add button just creates a bunch of fields in the first row, first td.

<h3>Line Items</h3>
<table>
  <tr>
    <th>Branch</th>
    <th>Department</th>
    <th>Invoice #</th>
    <th>Amount</th>
    <th>Transaction Type</th>
    <th>Deposit (y/n)</th>
    <th></th>
  </tr>
  <div class="fields"><tr>
    <td>
      <input id="transaction_line_items_attributes_0_location_id" name="transaction[line_items_attributes][0][location_id]" size="30" type="text" />
    </td>
    <td>
      <input id="transaction_line_items_attributes_0_department_id" name="transaction[line_items_attributes][0][department_id]" size="30" type="text" />
    </td>
    <td>
      <input id="transaction_line_items_attributes_0_invoice_num" name="transaction[line_items_attributes][0][invoice_num]" size="30" type="text" />
    </td>
    <td>
      <input id="transaction_line_items_attributes_0_amount" name="transaction[line_items_attributes][0][amount]" size="30" type="text" />
    </td>
    <td>
      <input id="transaction_line_items_attributes_0_transaction_type" name="transaction[line_items_attributes][0][transaction_type]" size="30" type="text" />
    </td>
    <td>
      <input id="transaction_line_items_attributes_0_deposit" name="transaction[line_items_attributes][0][deposit]" size="30" type="text" />
    </td>
    <td><input id="transaction_line_items_attributes_0__destroy" name="transaction[line_items_attributes][0][_destroy]" type="hidden" value="false" /><a href="javascript:void(0)" class="remove_nested_fields" data-association="line_items">Remove</a></td>
  </tr>
  <td><a href="javascript:void(0)" class="add_nested_fields" data-association="line_items">Add</a></td>
  </div>
</table>

I've tried placing the .link_to_add in a few places, but it doesn't put them in their own row.

Is there an easy way to go about adding a row of input boxes each time?

Answer 1

This helped me a lot: https://github.com/ryanb/nested_form/wiki/How-To:-Render-nested-fields-inside-a-table

By default fields_for inside nested_form_for adds <div class="fields"> wrapper around every nested object. But when you need to render nested fields inside a table you can disable default wrapper using :wrapper => false option and use the custom one:

<table>
  <%= f.fields_for :tasks, :wrapper => false do |task_form| %>
    <tr class="fields">
      <td>
        <%= task_form.hidden_field :id %>
        <%= task_form.text_field :name %>
      </td>
      <td><%= task_form.link_to_remove 'Remove' %></td>
    </tr>
  <% end %>
  <tr>
    <td><%= f.link_to_add 'Add', :tasks %></td>
  </tr>
</table>

Note: You need to specify id field. Otherwise fields_for will insert it after </tr>.

Also you need to override default behavior of inserting new subforms into your form using javascript:

window.NestedFormEvents.prototype.insertFields = function(content, assoc, link) {
  var $tr = $(link).closest('tr');
  return $(content).insertBefore($tr);
}

A similar technique can be used for lists, for compatibility with a jQuery UI sortable list.

If you are using simple_form then add the :wrapper => false option to the surrounding simple_nested_form_for call, otherwise it gets overwritten by the :wrapper => nil default.