devise, User#Update with remote => True, how to pass back errors?

I have rails 3 + devise. And I have the user#edit form using remote true.

Problem is I can't figure out how to handle errors. It's easy enough in the /registrations/update.js.erb to write JS to handle the success case, but how do I handle errors. I image I don't want that being handled in the JS file as a condition, right?

It might be nice to have something like:

respond_to do |format|
  if @user.errors.blank? == true && @user.save
    format.js
  else
    format.js { render :errors, :notice => @user.errors}
  end
end

But I 开发者_如何学运维don't see how to make that work with devise?

Any suggestions? Seems like a lot of devise users must have added remote-true to their user edit forms?

Thanks

---

It seems to me what you have should work. You have it all, you just did not show your .js partials which I'm sure you have':

Update

So for your routes you have:

app/config/routes.rb

devise_for :users, :controllers => {:registrations => "registrations"}

And for you controller you have:

app/controllers/registrations_controller.rb

class RegistrationsController < Devise::RegistrationsController
  def new
    super
  end

  def create
    super
    #or something similar to update.js
  end

  def update
  respond_to do |format|
    if @user.save
      format.js {render 'updated.js'} #or whatever the name of our file is 
    else
      @errors = @user.errors
      format.js { render 'errors.js'}
    end
  end
  end
end

And that doesn't work?