perf(javascript): skip nested callables during fingerprint traversal (#1871)

src/domain/javascript/javascriptSemanticTraversal.ts

@@ -1,7 +1,7 @@
 import * as t from "@babel/types";
 
 /**
- * Visit every Babel AST node in deterministic source-tree order.
+ * Visit Babel AST nodes in deterministic source-tree order, excluding skipped subtrees.
  *
  * `readAncestors` returns a snapshot during `enter`, outermost-first and
  * ending with the direct parent. Callers
@@ -17,6 +17,8 @@ export const traverseJavaScriptAst = (
 
 /** Callbacks for one deterministic AST traversal. */
 export interface JavaScriptAstVisitor {
+  /** Omit a child and its subtree without entering or exiting it. */
+  readonly skip?: (node: t.Node) => boolean;
   readonly enter: (
     node: t.Node,
     parent: t.Node | null,
@@ -50,6 +52,7 @@ export function* traverseJavaScriptAstSteps(
       current.nextIndex += 1;
       if (visited % 1024 === 0) yield;
       visited += 1;
+      if (visitor.skip?.(child) === true) continue;
       pending.push(enter(child, current.node));
     } else {
       visitor.exit?.(current.node, current.parent);