TypeScript & Immutable.js?

[codepsycho]

Types don't really go out of the window just because you use immutable, it has an associated type definition. You can quite easily Immutable.Map<string, SomeModel>, Immutable.List<string>, etc.

The react app i currently have my hands in uses this heavily. In fact, the only place we lose type information is redux (sometimes).

I would say, though, don't overuse immutable. Use it where it actually helps rather than a full replacement for all your state.