JS is actually not that great for this IMO. You probably need an NPM package to even deal with YAML because JS has a shitty standard library.

Sticking to a scripting language with a strong standard library is way better.

Any unix system can get Ruby/Python and read/write YAML/JSON immediately without caring too much about versions.

Of course in today's upside down world most developers seem to only know JS, so it would at least be "familiar". Still a bad choice in my view.

The way this industry is going, give it a few years and we'll have React-Kubernetes for generating templates. And I wish I was joking.