Typescript vs Dart?

Typescript is an incredible language. Its success is well earned. But there are real downsides about that, right? It'se semantically close to java script - and a lot of people don't like it. If users are happy with dart, i'm happy for them. So why use dat when typescript exists for cascript? Use case. And does this mean, if i use type safety and compiled to tapescript, i don't have to have a use typescript? Yes.