I’ve replaced Asio recently with stright epoll event loop and got about 16% RPS better. That is for resonably sized SQL server, so be careful with nice precanned libraries.
I would argue that _premature_ abstraction is worse than _some_ duplication of code.
Also I’ve seen the kind of codebase that seems to be LZW packed due to the sheer desire to DRY everything out. Not pleasant thing, by the time you goto 10 layers deep on some “helper” function you forgot why you in there.
There is a big difference between JIT compiled _dynamic_ language and ahead of time compiled static language. While modern JS engines show that difference sometimes can be narrowed down with sophisticated JIT and runtime, it is still there.
On a related note getting my share of data back from OneDrive was a painful exercise - tons of spurious write errors I spent best part of my evening getting everything back to my filesystem. Yes remote by default was enabled without my consent.
I too adopted Scala in 2014 and was really satisfied with FP side and how it all was tied with JVM. Honestly I always felt that JVM is a nice platform with a horribly verbose “assembly” language that is Java.
Fast forward to around 2020 and I had to organize a team to build search engine in JVM. Given how hard it is to find decent Scala developer I surrendered and did this project in Kotlin. Java devs easily pick up and write sensibly FP-style even code, and builtin coroutines are cool. Even though I had to open up the internals of coroutines to get tracing to work they felt a very welcome change compared to say monadic explicit async.
So for me Kotlin is kind of watered down Scala for typical Java folks and I could tolerate it compared to perspective of writing plain Java.