You're quite correct. My team just inherited a large node codebase that had proxy sprinkled everywhere, complete with a custom undocumented dsl written using proxies. It was a nightmare to learn, hard to extend without breaking and resulted in quite a few refactoring sessions.

I think proxies have their place, but most apps don't need them imo

I've been using Immer which relies on proxies to give you a plain object interface but also copy on write immutability.

It's very nice and I think is a practical example of when proxies make sense. However it does at times suffer from the cost of doing magic: you handle them in unusual ways and suddenly they break a lot.

Yea, you’re right, I can see that working in the right context. These ARE essentially DSLs, though, so their success largely depends on hard to define things like documentation, coupling, and quarantining to expected places.

Absolutely!