babel-check-duplicated-nodes

Babel helper utility (v1.0.0) that checks an AST for duplicated nodes, throwing a descriptive error if any are found. Originally extracted from Babel's test fixture runner, this tool helps Babel transform authors catch subtle bugs caused by node reuse. It is a niche package with a single API call, no active release cadence, and is intended for internal use during transform development rather than general production.