new visitor with scope info

[JSerFeng]

Scope is hard to deal with in some certain plugi transform. It is very useful if we can get scope information of current visiting node.
We dont need to use Arc or Rc, we can make a new Scope instance every time we enter a node, like what have done in visit_with_path.
We can do this by:

• In resolver, add a stxt in block or function or any other node that will need to create a new scope. And then, every time we enter a node that need to create scope, we can iterate all nodes with the same stxt at current scope, then create scope instance based on that, and pass it to the visitor.

How do you think of that, willing to contribute.

Also if you think this is a good idea, what field should the scope contains, and what should I do if I want to both use scope and path feature, visit_scope_and_path? Or add visit with context, and the context can have the field path and scope based on the feature.

[kdy1]

Adding the contexts to BlockStmt/Function from the resolver pass is fine, but I'm not sure about the extra.
I think it can be a third-party crate at the start, though.

[JSerFeng]

Thanks for reply, that's great enough, I'll make a PR to add stxt to BlockStmt and Function

[hyf0]

@JSerFeng You could use https://github.com/swc-project/swc/tree/main/crates/swc_ecma_usage_analyzer.

The minifier use it to do scope analysis. It might be enough/overload for simple use cases.

[kdy1]

I decided not to apply syntax contexts to the blocks or functions from the resolver because there are lots of passes between the
resolver and the minfiier, and there's no constraint about the syntax contexts of those nodes.

[JSerFeng]

Got it

[JSerFeng]

Is there any useful tools I can use to deal with something about scope ?

[kdy1]

AFAIK, no. The visitors I mentioned were enough for me.

[JSerFeng]

Alright, thanks for reply