Serialize watchify cache?

So I tried serialising the watchify cache using JSON.stringify and parse,
When starting watchify again with the saved cache it builds fine (and quickly),
but the watches seem not to be in place, as no file changes trigger an update event.

I took a quick gander through the source code and it wasn't super obvious why,
I'm busy at the moment but will try to fix (unless this isn't desirable for some reason) in a few days.