Yes, they did. But they did not close their borders (or ban travellers from affected countries, for that matter).
Didn’t close their borders? Depends what you yourself define here as not being closed. Right at the very beginning, there was a border closing.
Have the states that surround New Jersey put their ports and borders on red alert? Have they even instituted a significant increase in border guard activity around New Jersey’s borders?
Tell me why all the states around New Jersey shouldn’t do theses things.