[newlisper]

so I'm curious what's going on under the hood

https://en.wikipedia.org/wiki/Persistent_data_structure

Maybe GC is just a lot better than I think.

Yes, Clojure relies heavily on the JVM's GC being very good. It trashes it like there is no tomorrow and it would be a lot of work and extremely hard for an implementation of Clojure from scratch to match the performance of Clojure in the JVM because of how good the JVM's GC is.

Having said that, I have move 3 projects (10k-20k LoC) to JS from Clojure and don't plan creating new ones in Clojure, the JS projects ended up being faster, shorter and easier to understand. Idiomatic Clojure is very slow, as soon as you want to squeeze any little performance out it your code base will get ugly really fast. Learning Clojure is nice for the insights but I'll will pick nodejs first any day for new projects. Even if I need the JVM, my first choice probably will be Kotlin and then Clojure.

Of course there are many more downsides to using Clojure. No ecosystem, the cognitive overhead of doing interop with over-abstracted over-engineered Java libraries(because of no ecosystem ;)), the horrible startup times, the cultist community and the interop is really not that good, sometimes you have to write a Java wrapper over the Java lib to make it usable from Clojure. The benefits over JS are minimal but the overhead and downsides are too much. Worth learning it but not worth using it for real production projects.

[zdragnar]

Is there anything in particular that you had to give up to make the move (aside from thr jvm)? I am assuming that for node.js to be shorter and faster you avoided the bigger frameworks (next, typeorm etc) and had to stick pretty close to basic middleware ala express.

[cutler]

This is what bugs me about the Node.js cult - it's often compared with Rails, Django and Laravel which is just nonsense. Even Express isn't the same as plain Node. Plain Node.js is only comparable to something like Golang's net/http, Ruby's rack or raw imperative PHP with no classes. Once you add the kind of scaffolding included in Rails and Django Node.js slows down rapidly with significant memory bloat. Try Redwood - the latest Rails-in-Node and observe the memory footprint.

[thom]

I’m intrigued by what kind of code you’re finding is shorter and faster in JS. I’ve had the opposite experience, even limiting Clojure to a single thread.