There is something to be said for the bitmasks that are so common in C, createUser(user, ADMIN | SENDMAIL); has a lot more clarity than createUser(user, true, false, true);

I don't mind the object approach used here but its quite verbose in comparison even in Javascript. Having to name the variable and set whether its true or false is a lot more than needs to be done. Booleans in general have quite poor readibility and maintenance especially if a third possibility arrives.