That sounds incredibly baroque, complicated, and fragile.

Sure it is, but so what? Would statically analyzing the code really get you any further?

Type inference would get you quite a way. Using a language that allows effective tooling would get you even farther.

Replacing Javascript with a better language has not been possible thus far. There have been many attempts, but getting every browser maker to agree on something is like herding cats.

So, when life gives you lemons, you make lemonade. We're stuck with Javascript. Personally, I think running the code while you're developing it is a brilliant way of dealing with the problem of how to do proper autocomplete on a dynamic language.

.. in other words, javascript