jsFiddle here.

If deep copying worked, the output would be Curious George and not Ender's Game. How can I make a deep copy? An answer to this question indicates that $.extend(true, [], obj) creates a deep copy. Yet my example shows that it doesn't.

function Person(){}

Person.prototype.favorite_books = [];



var george = new Person();

george.favorite_books = [Curious George];



var kate = new Person();

kate.favorite_books = [The Da Vinci Code, Harry Potter];



var people = [kate, george];



var people_copy = $.extend(true, [], people);

people_copy[0].favorite_books[0] = Ender's Game;



$('#text').text(people[0].favorite_books[0]);

SOLUTION

I updated the jsFiddle. It turns out I need to deep copy each object in the array individually if the object is a custom object (that is, $.isPlainObject returns false).