Skeptical of rewriting JavaScript tools in "faster" languages

> I’ve written a lot of JavaScript. I like JavaScript. And more importantly, I’ve built up a set of skills in understanding, optimizing, and debugging JavaScript that I’m reluctant to give up on.

It's not that hard to do the same for a less terrible language. Choose something markedly different, i.e. a low level language like rust, and you will learn a lot in the process. More so because now you can see and understand the programming world from two different vantage points. Plus, it never hurts to understand what's going on on a lower level, without an interpreter and eco-system abstracting things away so much. This can then feed back into your skills and understanding of JS.

I swear some JS devs will go out of their way to avoid learning anything else, whilst simultaneously and breathlessly espousing that we rewrite everything else in JS.

It's usually the opposite. And the post is specifically about making JavaScript tools, why would you not expect them to be written in JS? I guess not making tools for say, c# devs in c# would also be bad?

Presumably because, apart from Python (see Ruff, uv, etc) most languages aren’t running into such major issues with their own “self hosted” tooling that it’s worthwhile to rewrite several of them in a completely different language.