This article explores a lot of things bundled together. One morsel to take away is the bit about inbound data validation. Type systems needs to work statically

This article explores a lot of things bundled together. One morsel to take away is the bit about inbound data validation. Type systems needs to work statically as well as at runtime via some kind of reflection API. This way you can unmarshal the data that comes over the wire directly into your language's type system. With JavaScript+TypeScript/Flow, the static type system and the dynamic reflection system is split into two separate paradigms, which in my opinion makes things rather complicated to the point of sacrificing developer productivity.