Easy adding/removing in nested forms for simple_form (javascript)

nested_forms.js

var Forms = {

  generatedId: function() {
    return String(new Date().getTime());
  },

  applyAddFieldsBehaviour: function() {
    var self = this;
    $('.add_fields[data-content]').each(self._applyAddFieldBehaviour);
  },

  applyDestroyFieldsBehaviour: function() {
    var self = this;
    $('.destroy_fields').each(self._applyDestroyFieldBehaviour);
  },

  _applyAddFieldBehaviour: function() {
    var element = $(this);

    if(!element.hasAddFieldsBehaviour) {
      element.hasAddFieldsBehaviour = true;
      element.click(Forms._handleAddClick);
    }
  },

  _applyDestroyFieldBehaviour: function() {
    var element = $(this);

    if(!element.hasDestroyFieldsBehaviour) {
      element.hasDestroyFieldsBehaviour = true;
      element.click(Forms._handleDestroyClick);
    }
  },

  _handleAddClick: function(event) {
    var button = $(event.currentTarget);
    var nav = button.closest('nav')

    nav.before(Forms._htmlForNewRecord(button));
    event.preventDefault();
    Forms.applyDestroyFieldsBehaviour();
  },

  _htmlForNewRecord: function(addButton) {
    html = addButton.attr('data-content');
    html = html.replace(/_new_/g, '_' + Forms.generatedId() + '_');
    html = html.replace(/\[new\]/g, '[' + Forms.generatedId() + ']');

    return html;
  },

  _handleDestroyClick: function(event) {
    var button = $(event.currentTarget);
    var form = button.closest('form');
    var fieldset = button.closest('fieldset');
    var idField = fieldset.next('input[type=hidden]');

    form.append('<input type="hidden" name="' + button.attr('data-id') + '[_destroy]" value="1">');
    fieldset.remove();

    event.preventDefault();
  }

}

$(function() {
  Forms.applyAddFieldsBehaviour();
  Forms.applyDestroyFieldsBehaviour();
});