Since 2.1 ts is becoming a de-facto default choice for any serious JS projects I'd say. In conjunction with VSCode it really shines and makes JS sometimes even enjoyable...

But there is an issue that quirks our team almost daily: the bolted-on typesystem provides a false sense of safety. You can look at an API response, write an interface for the data structure, build functionality ontop of it, and when the API response structure changes in subtle ways over time, everything may break without notice. There is no way to enforce an interface through casting anywhere, not even via some code generation or sth like that.