Flow Infers Types "Local" to Modules ❤️

I wish to have a type system where I only need to type-hint the published parts (of a module/file) and let the type system infer all internal types. Though, I learned that even in Haskell land it is referred to as good practice to still type every function, no matter if public or private. Flow sounds to be doing what I want.

Fortunately, JavaScript is already written using files as modules, so we modularize our analysis simply by asking that modules have explicitly typed signatures. (We still infer types for the vast majority of code “local” to modules.) Coincidentally, developers consider this good software engineering practice anyway.