Looking forward to the results. If this is merged, I'm also gonna remove my fork of the repo, as people may think they should use my basic example. Which only was to illustrate ‘it works’ in the first case.

One issue I've come across with this solution is that the new fields template is still submitted through the form. Therefore if you remove this from the accepts_nested_attributes_for call...

:reject_if => lambda { |a| a.values.all?(&:blank?) }

Then it will attempt to create a model for the new fields. One solution would be to move template outside of the form entirely, but then you do not have easy reference to the form builder which becomes an even bigger problem for deeply nested models. Any ideas?

You can see the work I've done so far on unobtrusive-jquery and unobtrusive-jquery-deep branches. The latter currently does not work due to the problem mentioned above.

Hey guys,

I've made 2 different fixes for this problem.

1. Modify the :reject_if condition to only consider the real attributes of the nested object only. It will ignore blank attributes of that nested object's children.

2. Move the child field templates outside of the form. They will only appear once each, at the end of the form. This is more efficient (only one instance of each hidden template div), but then you lose the context of all the generated IDs in the name attribute of each input element. I added some JavaScript to ensure that these are inserted when clicking "new child". This approach doesn't require any reject_if condition in the model.

These are available at http://github.com/timriley/complex-form-examples/tree/unobtrusive-jquery-deep-fix1 and http://github.com/timriley/complex-form-examples/tree/unobtrusive-jquery-deep-fix2 respectively.

What do you think?

I just updated the javascript in my unobtrusive-jquery-deep-fix2 branch to make the form work properly when editing previously existing projects: http://github.com/timriley/complex-form-examples/tree/unobtrusive-jquery-deep-fix2

Does the example application here work properly for you? If so then there must be some difference between the example application and your application which is causing these bugs. It's hard for me to say what that could be.