Duplicated AST nodes often lead to obscure bugs. This module checks your AST and throws a helpful error if you include a duplicated node in your output. It's useful when authoring babel transforms.
This piece of code was originally written by @nicolo-ribaudo and is included in @babel/helper-transform-fixture-test-runnner.
import checkDuplicateNodes from "@babel/helper-check-duplicate-nodes";
checkDuplicateNodes(ast);