The problem in my experience is that while nil is a perfectly reasonable default 9/10 times that 1/10 happens often enough and causes major problems that it is worth taking the extra few seconds to write it explicitly in the code to acknowledge that case and that you have checked that it is fine in the 9/10 cases or handle it in the 1/10 case.

I have seen multiple major production outages in Golang code because people accidentally read a non-existent map key and used the default value. As a funny bonus in one of those cases we were stumped when debugging because this code had tests, but the tests were also reading the default values out of the map and asserting that "" was in fact a valid textproto (it always is!) so silently testing nothing.

So even if defaults are useful 9/10 times that 1/10 is so painful and expensive that it isn't worth it in my experience. The time spent responding to, debugging and fixing those outages far, far outweighed the time saved by the convenient default values in the 9/10 times.

For me: documentation at the "front door" of an interface, especially in that long moment before you decide to add a spec or Malli schema.

Well, kind of. This is the kind of problem that you might throw schemas (eg. Malli) at pre 1.13.

It’ll be nice to have it at hand in the base language though.

What is nil-punning?

Working on it :)

It'll take a while but now other programming languages look alien to me. Once you've adopted s-expressions it is hard to go back.

Amazing! What are the most interesting areas for ClojureScript in the future, if you don't mind me asking for some casual semi-serious prediction?

Thanks for everything you've done for Clojure and ClojureScript, I'd surely have dropped programming as a whole if I didn't discover Clojure and ClojureScript at the time I did.

Seems additive to me; no breaking changes, and better control and error messages when opting in for it, seems entirely Clojurely to me.

It's 100% opt-in at the call site and doesn't affect existing code, so no?

Many people (including myself) already have checked key variants for maps; this mainly extends the syntax to destructuring too.

Howso?

The maps haven't changed at all, this is a feature at destructuring sites.

Honestly what's mostly at the forefront of my mind is greatly improving the documentation around ClojureScript as well as our fork of Google Closure Library (GCL). At work we've switched to DataStar (a single JS include) and coupled that with ClojureScript/GCL - we no longer rely on anything from NPM, to call this a simplification would be a gross understatement. Bundle size is 30K gzipped and we spend no time thinking about our build or JS tooling/dependency tomfoolery.

So less about ClojureScript specifically, and more generally how I think we're well situated for people looking for a way out. The current mainstream practice dead end is bigger than the one that made React (also originally just a script tag include) appealing to me back in 2013. There are of course many ways forward that don't involve CLJS, but I think ClojureScript/GCL and the new crop of NPM-dep free pure CLJS solutions like Replicant are well situated for folks who can see that accepted practices are not delivering enough value even with AI assistance.