I had what started off as a simple function node where the code has gotten much more complex as I have been addressing a variety of corner cases. Unfortunately all of that complexity has hidden some bugs. I really need to be able to step through the code to sort it out. Ideally I would be able to use the Chrome debugger, but I found this from quite some time ago:
Is that an accurate sumation of what is possible?
I had been contemplating at some point actually building my own custom nodes and this may push me over the edge to do it, but I such a long to do list, I wasn't jumping at the chance to go there yet.