...
Now, notice that the book object representing "The Giver" by Lois Lowry,
takes part in both collections. This is another example how two
different JSON objects share a single third JSON object.
One could argue that these are two different JSON objects that happen to
represent the same book. This is not true, because these "two objects"
cannot have their own different data and if we want to change, for
example, the year when the book was written, we must make the change in
both of these "two objects".
Well, actually, there is nothing to indicate that these two objects are
the same. A javascript engine would create two objects, and if you were
to change the properties of one, the other's properties would not
automatically change.