# Error Handling
Since this tool is a core extension tool of @babel/core, an error will occur when there is a risk of overwriting the original function of @babel/core so that it can be used safely. In addition, if the definition of helpers does not follow the rules, an error will be issued.
# Error List
| Error | When | Description |
|---|---|---|
| AlreadyImplementedError | core extension | unknown:This tool cannot be used. officially supported.\nPlease see the official documentation.https://babeljs.io/docs/en/babel-helpers |
| AlreadyImplementedError | core extension | unknown: objectWithoutProperties cannot be used because it is supported by babel official.\nPlease change the name of the helper. |
| NotFoundError | core extension | unknown: Not found UDF helpers. |
| ReferenceError | traverse helpers | unknown: Unknown helper helperName |
| SyntaxError | traverse helpers | unknown: UDF Helpers can only import a default value (This is an error on an internal node. Probably an internal error.) |
| SyntaxError | traverse helpers | unknown: UDF Helpers should give names to their exported func declaration (This is an error on an internal node. Probably an internal error.) |
| SyntaxError | traverse helpers | unknown: UDF Helpers must be a function declaration (This is an error on an internal node. Probably an internal error.) |
| SyntaxError | traverse helpers | unknown: UDF Helpers can only export default (This is an error on an internal node. Probably an internal error.) |
| SyntaxError | traverse helpers | unknown: UDF Helpers can only export default (This is an error on an internal node. Probably an internal error.) |
| SyntaxError | traverse helpers | unknown: UDF Helpers must default-export something. |
See the tests if you want to know exactly when the error occurred.