This biggest "aha" benefit I get from TypeScript is that it is structurally typed, while Java is nominally typed. In my experience it has proven much easier to refactor in TS because I just need to ensure my objects have all the right properties. With Java if I have a Thing1, but a library is updated to add just a single new property so now there is a Thing2 type, well now then all the places I need a Thing2 I have to completely copy over from Thing1 - I can't just add the property and be on my merry way. This happened to me many times in my Java career - I still think I have PTSD having to do a Jersey 1.x upgrade to a Jersey 2.x version across a large codebase. It was a nightmare I've never had anything come close to with Typescript.

> I mean, this is a web-first language that has no concept of sending objects over the wire.. okay then.

I have no idea what you're talking about here. I use GraphQL with auto typegen of my TS types and I get typed data objects everywhere.

> TypeScript's generics system is cute, but I think it's mostly academic.

TBH this remark just makes me thing you really don't know much about TS. I use generics extensively, find them very helpful and are easy to use.

I'll give you the point on initial TS setup being non-trivial. Hopefully advances in tooling (things like Deno, which I'm not actually a huge fan of, or other projects like Rome) will make this easier, but even then I found this to be a "one and done" cost.