Refactor transformer to use the instance of AstBuilder which is in TraverseCtx everywhere

[overlookmotel]

AstBuilder is the object which you use to generate AST nodes. It is heavily used in the transformer.

We currently have 2 copies of AstBuilder in transformer:

• 1st copy is stored in TransformCtx
• 2nd copy is stored in TraverseCtx.

This is problematic for 3 reasons:

1. It blocks us from doing Move TransformCtx into TraverseCtx backlog#144, which will be a performance boost.
2. For the introduction of AST node IDs (RFC: AST node IDs #5689), AstBuilder will become stateful, containing a counter for creating unique IDs. So only a single copy of it can exist.
3. It's rather messy! Why do we have 2 copies anyway?

We need to go through the transformer and swap all uses of AstBuilder from TransformCtx over to use the copy in TraverseCtx.

For example:

oxc/crates/oxc_transformer/src/react/jsx_source.rs

Lines 92 to 96 in 1cee207

	let key = self.ctx.ast.property_key_identifier_name(SPAN, SOURCE);
	let value = self.get_source_object(line, column, ctx);
	self.ctx
	.ast
	.object_property_kind_object_property(SPAN, kind, key, value, None, false, false, false)

Should become:

let key = ctx.ast.property_key_identifier_name(SPAN, SOURCE); 
let value = self.get_source_object(line, column, ctx); 
ctx.ast.object_property_kind_object_property(SPAN, kind, key, value, None, false, false, false)

This will require passing TraverseCtx into some functions which it's currently not available in.

I have marked this as "good first issue" as it's not too technically tricky (but then again, there are always some unforeseen complications!), but is a good opportunity for anyone interested in the transformer to get to know the codebase.

Would anyone be able to help please?

[shulaoda]

🙌 I'm happy to

[shulaoda]

I found that there is also an AstBuilder instance in module_imports of TransformCtx. Does this need improvement?

[Dunqing]

I found that there is also an AstBuilder instance in module_imports of TransformCtx. Does this need improvement?

Leave module_imports for me, I am going to refactor it.

[overlookmotel]

Closed by #6173 and #6209. Thanks @shulaoda!