[gcanti]

> I was hooked on the idea of having a type safe data record that was also immutable

Me too, thus I wrote https://github.com/gcanti/tcomb

[stephanos2k]

[Author here.]

That's very cool! But it's runtime checking only, right? I was aiming for compile-time checking.

[gcanti]

Yep. However static and runtime type checking are not mutually exclusive. Actually there's a TypeScript definition file included in the repo. Moreover such a runtime type checking brings additional features like refinement types and runtime type introspection