A Rails gem to conveniently manage multiple nested models in a single simple_form. It does so in an unobtrusive way through jQuery.

Note: this gem extends the simple_form gem (github.com/plataformatec/simple_form)

Add it to your Gemfile

gem "nested_form", :git => "git://github.com/binarycode/nested_form.git"

Run

bundle install

Run the generator

rails generate nested_form:install

Running the generator will add a file at public/javascripts/nested_form.js which should be included after jQuery.

<%= javascript_include_tag 'jquery', 'nested_form' %>

You can then generate a nested form using the nested_form_for helper method.

<%= nested_form_for @project do |f| %>

Use this form just like normal, including the simple_fields_for helper method for nesting models. The benefit of this plugin comes from the link_to_add and link_to_remove helper methods on the form builder.

<%= f.simple_fields_for :tasks do |task_form| %>
  <%= task_form.input :name %>
  <%= task_form.link_to_remove "Remove this task" %>
<% end %>
<%= f.link_to_add "Add a task", :tasks %>

This generates links which dynamically add and remove fields.

[Somehow this was not working with Ryan Bates’s initial gem but should work ok with this fork].

It is often desirable to move the nested fields into a partial to keep things organized. If you don’t supply a block to fields_for it will look for a partial and use that.

<%= f.simple_fields_for :tasks %>

In this case it will look for a partial called “task_fields” and pass the form builder as an f variable to it.

You can limit how many children a user can add by setting the :limit option :

<%= f.link_to_add "Add a task", :tasks, :limit => 2 %>

This gem is based on the plugin by Ryan Bates: github.com/ryanb/nested_form