Efficient way to get a class reference from a given instance

[pimterry]

Given an instance (matched dynamically) I want to directly access the corresponding class (so that I can patch a target method for all instances).

This feels like something that it should be possible to do efficiently, but the best way I can see to do this right now is with Java.use(instance.$className). That seems likely to be slow and potentially error prone (if the instance comes from an unexpected classloader, for example).

There is an instance.class property, but this returns <instance: java.lang.Class>, rather than <class: $CLASS_NAME>. There's also various $-prefixed single character fields, but I assume those aren't intended to be used directly, and none seems to obviously provide this.

Is there a more direct way to do this? Am I wildly off track somehow?

If not, would you be open to adding a method for this? I'd be happy to open a PR. I think in general, it might be useful to add a small section to the docs related to this, defining the JS API that's available (e.g. $className) on Java instances and classes.