GitKraken Desktop is a large Electron/React project dating back to 2014. We picked Flow as our first type system for JS by around 2017 and for reasons that we will dig deeper into in this talk, you will see why we switched to TypeScript and some of the challenges we faced along with that migration. Some of those challenges include incredibly long dev loops due to type checking as well as a lack of support for Flow from our dependencies. You will hear about how one dev on a mission decided to tackle this monumental effort on his own time.