If you want types like Java, TypeScript's probably a good choice. However, if you want the flexibility or the guarantees a powerful type system gives you, TypeScript's not going to cut it.

I've written quite a lot of TypeScript, and I generally feel very productive in it, but occasionally I feel like I want more from the type system (type classes, rank-N types, sum types, etc.) and tidier syntax. You might be interested in Bodil Stokke's recent Strange Loop talk, where she discusses why she switched from TypeScript. https://www.youtube.com/watch?v=yIlDBPiMb0o

Or Dart for that matter?

The advantage is that types aren't optional. People actually have to respect them.