Who is Nana from the book Peter Pan and what her job?

There's no character named Nana in JM Barrie's classic children's novel, Peter Pan. However, there is a Newfoundland dog named Nana who is a prominent character in the story. Nana is the beloved nanny to the Darling children, Wendy, John, and Michael. She looks after them, taking care of their practical and emotional needs, while their parents are away.