Brainstorming uart.js functionalities

That looks great! While dump does work, it does dump everything. You could just print Object.keys(global)?

Good point about eval(undefined). Does this actually fail, or is it that accessing a variable that doesn't exist is causing a reference error?

I'm not sure if you found this, but you might be able to make get return a function, but with a valueOf method (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/valueOf) that got the value rather than executing a function? It seems that querying the type might be preferable anyway though.