Cocoon gem: How to limit the number of associations

Question

I am trying to use the Cocoon gem to add users to an asset. The only issue is that I need to have it set up to limit the amount of user associations that can be applied to an asset based on the type of asset they are (hardware/software, with hardware being 1, software won't be defined). At the moment I can just keep adding user associations to the asset. Is there any way to limit the amount of associations?

Any help is appreciated. Thank you in advance.

Asset.show:

- if @asset.users.empty?
      = simple_form_for([@asset_profile, @asset]) do |f|
        #assets_users
          = f.simple_fields_for :assets_users do |assets_user|
            = render "assets_user_fields", :f => assets_user
          .links
            = link_to_add_association "Add Another User", f, :assets_users
          = f.submit

_assets_users_fields.html.haml:

.nested-fields
  = f.input :user_id, collection: @users.order(:last_name), :label => "User"
  = link_to_remove_association "Remove", f

I tried a solution I saw on another question, but I am getting an error stating Uncaught TypeError: number is not a function at if $("#assets_users .nested-fields").length() is 1.

The javascript I tried:

$ ->
  check_to_hide_add_link = ->
    if $("#assets_users .nested-fields").length() is 1
      $("#assets_users .links a").hide()
    else
      $("#assets_users .links a").show()
    return
  $("#assets_users").bind "cocoon:after-insert", ->
    check_to_hide_add_link()
    return

  $("#assets_users").bind "cocoon:after-remove", ->
    check_to_hide_add_link()
    return

  check_to_hide_add_link()
  return

Once again, any help is much appreciated.

EDIT: Link to referred question: Cocoon add association, how to limit number of associations

Generated javascript:

$(function() {
  var check_to_hide_add_link;
  check_to_hide_add_link = function() {
    if ($("#assets_users .nested-fields").length() === 1) {
      return $("#assets_users .links a").hide();
    } else {
      return $("#assets_users .links a").show();
    }
  };
  $("#assets_users").bind("cocoon:after-insert", function() {
    return check_to_hide_add_link();
  });
  $("#assets_users").bind("cocoon:after-remove", function() {
    return check_to_hide_add_link();
  });
  return check_to_hide_add_link();
});

Answer 1

Getting rid of () on .length ended up being the solution for the error message. Just a problem with my conversion of javascript to coffeescript.

Here's a link to the new question I opened up to further delve into my specific problem, in case anyone has the same: Javascript: Using a method from model in javascript code