Generic Repeatable Fields

generic_fields.js

  $('a[data-add-nested]').live('click', function(){
    var regexp = new RegExp($(this).data('add-nested-replace'), "g")
    target = $(this).data('add-nested-target')
    new_stuff = $($(this).data('add-nested').replace(regexp, (new Date).getTime())).hide()
    if(!target || target == 'before') {
      new_stuff.insertBefore($(this))
    } else if(target == 'after') {
      new_stuff.insertAfter($(this))
    } else {
      new_stuff.appendTo(target)
    }
    new_stuff.slideDown()
    return false
  })

generic_helper.rb

module GenericHelper
  class GenericFormObject
    def to_param
      @to_param ||= "new_repeated_fields_#{Time.now.to_i}"
    end
    def method_missing(sym, *args, &block) end
  end  
  def link_to_add_generic(label, f, nested, initial = 1, link_options = {}, &block)
    new_object = GenericFormObject.new
    reuse_fields = f.semantic_fields_for(nested, new_object) do |n| capture_haml(n, &block) end
    
    returning [] do |a|
      initial.times { |i| a << reuse_fields.gsub(new_object.to_param, i.to_s) }
      a << link_to(label, '', link_options.merge('data-add-nested' => reuse_fields, 'data-add-nested-replace' => new_object.to_param))
    end.join
  end
end

report_form.html.haml

- semantic_form_for 'report', :url => generate_report_path, :html => {:method => :get} do |f|
  = link_to_add_generic 'Add Field Set', f, 'field_set[]' do |g|
    - g.inputs 'Field Set' do
      = g.input :name
      = g.input :pick_one, :collection => %w(red green blue)

make repeatable fields in a form without a model using formtastic and haml