Im trying to create a .js (similar to Core.Agent.Znuny4OTRSShowPendingTimeIfNeeded.js), which the main function is show/enable specific dynamicField dropdown when a specific option are selected in Next State dropdown. All of this, for now, only affect ATPending action. This is my try so far:

$(document).ready(function() {
            setTimeout(function() {
                    const Action = Core.Config.Get("Action");
                    const SupportedActions = ["AgentTicketPending"];

                    if ($.inArray(Action, SupportedActions) !== -1) {
                        if (Action === "AgentTicketPending")
                        document.getElementsByClassName("Row Row_DynamicField_ApproverList")[0].style.visibility = "hidden";
                        $('#NewStateID').on('change', function() {
                                const Option = $(this).val();
                                if (Option === 'pending approval') {
                                    document.getElementsByClassName("Row Row_DynamicField_ApproverList")[0].style.visibility = "visible";
                                } else if (Option !== 'pending approval') {
                                    document.getElementsByClassName("Row Row_DynamicField_ApproverList")[0].style.visibility = "hidden";
                                }
                            }
                        );
                    }
                });
            });

Resume: When "pending approval" state is selected, DF "Approver" is visible.