I come from a java world and I can definitely see the difference in the power of the tools I have available in the js world. That said, I think it’s getting better and better, even without the help a more strict type system could provide.
I use eslint integrated on intellij idea and I can do a lot of the refactoring and quickly navigate on the code base, just like I’m used to do in Java.
Of course this tools cannot magically help you with types on regular js. but if you are doing tdd, it becomes very trivial too see and catch those kind of problems.
All of the aforementioned *caused by typo* errors will be catch by the lint and to be honest, most of the refactoring functionality I miss was only necessary because of the strong types in java, wich now I feel just slows everything down.
I don’t see any evidence that the author was trying to promote any idea of dichotomy between tests and types, he’s very clear on why HE is avoiding typescript and even suggests you to give it a try.