They have good defaults and Xcode is a good IDE with full support of these frameworks, Swift is a good language with sensible conventions so you don't really need to learn that much.
When you don't know something you can start typing keywords and see what Xcode autocompletes for and read the explanation about that function from the documentation that is provided to you right there. It's not perfect, sometimes there's no documentation but it's not a big deal as you can look into source files or try it out to see how it behaves.
It's not the same because in JS you usually would use a large number of libraries with varying degree of documentation and different conventions. Also, you would loose autocomplete when you expect to receive something as a parameter instead of defining it in that closure.
The basic language API is not that large, the benefit of autocomplete discovery comes when you have autocomplete on custom types of a specific framework accompanied with proper documentation.
I’m sure NestJS, which sparked this thread, has very complete type defs, as does any major framework out there.
You seem intent on dismissing something you obviously haven’t tried in the past couple years; next time I’d suggest a simple “I don’t like it” instead to save us all time.
When you don't know something you can start typing keywords and see what Xcode autocompletes for and read the explanation about that function from the documentation that is provided to you right there. It's not perfect, sometimes there's no documentation but it's not a big deal as you can look into source files or try it out to see how it behaves.