Need Help with Rails 2.3 Four Level Nested Form Javascript Function

Question

Hi I'm using Alloy's Complex Form Example found here. The example he provides is a two level hierarchy and I'm trying to expand it to four.

He has javascript functions for adding nested items. Can someone show me how to expand for four nested layers?

'.add_nested_item': function(e){
   el = Event.findElement(e);
   template = eval(el.href.replace(/.*#/, ''))
   $(el.rel).insert({    
     bottom: replace_ids(template)
   });
 },
 '.add_nested_item_lvl2': function(e){
   el = Event.findElement(e);
   elements = el.rel.match(/(\w+)/g)
   parent = '.'+elements[0]
   child = '.'+elements[1]

   child_container = el.up(parent).down(child)    
   parent_object_id = el.up(parent).down('input').name.match(/.*\[(\d+)\]/)[1]

   template = eval(el.href.replace(/.*#/, ''))

   template = template.replace(/(attributes[_\]\[]+)\d+/g, "$1"+parent_object_id)

   // console.log(template)
    child_container.insert({     
     bottom: replace_ids(template)
    });
 }

Thanks heaps for any assistance!

Answer 1

I think it's a bit overloaded form if you need to handle three-level hierarchy. rethink your UI first.

Other than that - i don't think you need to build your associated objects in controller since example app builds them (if necessary) in views (app/views/projects/_form.erb):

<% @project.build_author unless @project.author %> <% project_form.fields_for :author do |author_form| %>

Answer 2

Hey Todd,

Unfortunately this isn't really my area of expertise either…

Let me just state that I wouldn't use the example that's used in the complex-form-examples for so much nesting. Rather I'd build the required form inputs completely in JS with the regular DOM API. That should give you a much cleaner and leaner implementation and also better testable.

Cheers, Eloy

Answer 3

Ryan Bates has made this solution easy. Works with Rails 3 with helmerj's comment :)

http://railscasts.com/episodes/197-nested-model-form-part-2

helmerj's comment:

For the latest Rails3.rc ONe has to modify a single line:

in "module ApplicationHelper"

link_to_function(name, "add_fields(this, \"#{association}\", \"#{escape_javascript(fields)}\")")

which removes the not needed h() function. Otherwise works like charm.