So how was the refactoring experience this time ? Well the compiler was certainly my best buddy along the way. Obviously I also had to consult the documentation of elm-transit-router quite often. i had a few times where things appeared to be compiling fine in Light Table, but actually there was some error in a Module referred by Main. I’m not sure if it’s make’s fault or just that there is something missing in the elm-light plugin. I’ll certainly look into that. Always handy to have the command line available when you’re not sure about whether your IDE/Editor is tripping you up or not. I don’t think tests would have caught many of the issues I encountered. Forgetting to wire up inputs to startapp was probably my biggest blunder, and I’m sure no test would have covered that. I needed to know that this was something I had to wire up for it to work. RTFM etc.