The iOS/iPadOS app iSH is available on the app store and runs Linux via x86 emulation. And you can install Node.js on it!
Installing the Alpine Linux package manager apk: How is explained in the project’s wiki.
Fetching Alpine’s repository list:
apk update (source)
apk add nodejs
The Wiki has a list of packages that can be installed in the same manner.
If found out that running Node.js on iSH is now possible via a tweet by @asciidisco.