Being an electron app, Im surprised it only consumed 150 mb of ram and spawned 4 processes just by opening it.
for refernce, on win 10: whatsapp - 200+mb and 4 processes. slack - 325mb and 5 processes.
Well that's what you get when the "solution" is to embed a webserver, a browser, a native executable to show that browser, and the server runs Node...
The solution is simple, stop shoving square pegs in round holes, and learn an appropriate language rather than shoehorn JS everywhere.
Being that this app's sole purpose is to evaluate JS, this may be a situation where JS isn't being shoehorned
There's plenty of ide-libraries in other languages to replace the one used by runjs.
To me it would make sense to build a real desktop application and bundle whatever JS engine you want to use, pipe and process the output as any other application.
You'd end up with a much smaller application (Download size), more resource-efficient, and less reliance on things like the bundled browser.
None of these things I care about. I care about whether or not it serves a purpose to me. If it does, I'll use it. If it doesn't, I won't. You might have other priorities and that's your prerogative.
A solution to reduce the size could be to ship the Electron runtime similar to .NET, etc.
However, PWA's are probably going to be the best bet going forward.