Javascript. How to return multiple values using a comma?

scheduler.attachEvent("onEventSave",function(id,ev,is_new){ const keys = ev.username.split(','); const selectedUsers = users.filter(user => keys.includes(user.key)).map(user => user.label); ev.text = selectedUsers.join(','); return true; })

scheduler.attachEvent("onEventSave",function(id,ev,is_new) { var checked_users = ev.username.split(','); // translate string into a list of noted user id var with new_text = "; // here we write a string with user names var checked_users_count = checked_users.length; // number of checked users for (var i = 0; i < checked_users_count; i++) { var check_user_id = checked_users[i]; // current id noted var ch_users = users.filter(usr => usr.key == check_user_id); // get the person from the list of users marked for id (the output is also a list, but no more than 1 element) if (ch_users.length > 0) with new_text += (with new_text != "? ', ' : ") + ch_users[0].label; // is entered in the user row was found } ev.text = with new_text == " ? 'Nobody' : with new_text; // if no found then we denote this situation (Nobody) return true; })