I was messing with typescript recently and in my application I wanted to enforce deprecated settings sanitizing with the power of static type checking. Basically try and make some pattern that is extensible that if a field was to be deprecated it would force the programmer to sanitize that via removing it or migrating it into a new name, etc. I feel like I am close, but I might not know the exact in and out of guarding to get this to work how I want it.