How does Deno solve this? Genuine question by the way. I'm not trying to be snarky.
This limits the attack surface, when it comes to installing malicious dependencies, that npm happily installs for you.
So yes, I was wrong and my previous comment a hyperbole. A big problem is npm, and not JavaScript.
My point about the staggering amount of dependencies still holds though.
There have been attempts to do this kind of sandboxing before. Java and .NET both used to have it. Both dropped it because it turns out that properly sandboxing stuff is hard.