Yeah, not doing that when using typescript is leading to so many bugs. Yes the compiler is happy, but you will get a runtime error as the json decoding converte

Yeah, not doing that when using typescript is leading to so many bugs. Yes the compiler is happy, but you will get a runtime error as the json decoding converted it to a string, not the expected number type being passed around. So add in a second step that verifies that the decoded json actually matches the type and fail fast. One thing I liked about Elm was the decoders, a bit hassle to write but made it so easy catching bugs when backend and frontend people weren't on the same page.