I worked around the inbuilt properties in my loop so as to use the constructor where I could, just in case the constructor ends up doing something more interesting in the future.  Subject to your other comment, I guess that all properties could be deep cloned, and then I can test whether or not to call cloneBuffer afterward based on the flag.  On the deep cloning, do you have a favorite method?  How about https://github.com/pvorb/node-clone?