Previous discussion: gcanti/tcomb-form#377 (comment)

@eteeselink

what's your motivation for moving from flow to ts?

There's plenty of reasons (I should write down a list..), maturity over all.

Do you consider it the spiritual successor to tcomb?

Yes and no, io-ts has a narrowed scope and wants to align with the TypeScript type system at the cost of possibly sacrifice some feature

I'm only sad that I can't use typescript class or interface syntax with it

Not sure I'm following

What's the point of runtime type checking inside a 100% typescript project

Mainly for IO validation but there are 4 use cases I'm interesting in

• IO validation
• runtime type introspection (which makes possible something like tcomb-form)
• "static types extraction"
• refinements

An example (POC) https://github.com/gcanti/prop-types-ts. There you get static AND runtime safety (so you please both TypeScript and non TypeScript users) with a single schema definition