Don't get me wrong. I love PureScript and HKT but the fact that it requires complete buyout to Purescript ecosystem overwhelms my team members and becomes a hard sell. To build a PS layer on top existing JS libraries isn't straight forward. Now that they introduced so many breaking changes, it will take time for other PS libraries to catch up. May be I might go back to PS when 1.0 release happens and I hope many things are stable including libraries which I need in day to day full stack development.

Typescript in the last couple of years introduced a nice way to compose types and ways to get rid of many other common JS gotchas. They have type definitions for almost all the usable npm libraries, which helps you jump-start the development.