Hey, your mileage will vary! My workday includes Node.js being present on basically everything, so it's not overhead for me. (As others have pointed out it's also not that heavy a thing to have around, especially compared to Electron)
I... guess? Compared to an editor written in Rust? Sure? But how much CPU will an editor really consume?
As with most things outside of tight loops in games, good architectural decisions are going to matter a lot more than language choice. Premature optimization is the root of all evil, but if I see that the algorithm is inefficient in practice I'll change the algorithm.
VIM but particularly Emacs can get painfully slow on semi-large files (and forget about it if you have very long lines) and you have to tweak or disable lots of features if you want them to be reactive and not peg your CPU.
So I think it's more down to the implementation than the language it's written in. V8 is really efficient at running JS, what slows it down is the 25 levels of abstraction and indirection that is usually added on top of it. OP claims to try to reduce that, so maybe give it a chance?
