> Another options besides comment-based annotations is property based annotations. Basically provide a library that contains all the possible primitive types th

> Another options besides comment-based annotations is property based annotations. Basically provide a library that contains all the possible primitive types that can be checked and functions for composing higher order types. Shameless plug: I wrote a similar library based on set theory (I'm a mathematician) https://github.com/gcanti/tcomb https://github.com/gcanti/tcomb EDIT: and here an article explaining the rationale behind the library https://gcanti.github.io/2014/09/29/javascript-types-and-sets.html https://gcanti.github.io/2014/09/29/javascript-types-and-set...