Rails AJAX返回错误

Question

I am trying to understand Rails built in AJAX helper -> remote: true.

I have a link in a view (views/show) that calls a controller via AJAX:

<%= link_to 'My Profile', edit_user_path(current_user), class: 'user-profile', remote: true %>

Which hits the appropriate controller (controllers/users_controller.rb) with the appropriate fields (tested with byebug):

  def edit
    @user = User.find(params[:id])
    respond_to do |format|
      format.html { render plain: 'profile' }
      format.js { render plain: 'profile' }
      format.json { render plain: 'test' }
    end
  end

And I have my JS (javascripts/users.js) perform an action on ajax success or failure:

$(document).ready(function() {  

  $('.user-profile').on('ajax:success', function(event) { console.log(event) });

  $('.user-profile').on('ajax:error', function(event) { console.log(event) });

});

However, no matter what I try, the ajax:error function always executes and I cannot figure out why. Any ideas?