Appsync with NodejsFunction lambda resolver doesn't work with ESM format

AWS CDK provides the possibility to generate Lambda functions in ESM format. However it seems like Appsync cannot process this format (thanks @jogold).

You can find the original ticket here with all the details: https://github.com/aws/aws-cdk/issues/19210

Start with the linked AWS CDK issue 19210 and reproduce the AppSync resolver using a NodejsFunction Lambda in ESM format. No repository files or tests are identified; the work is complete when AppSync can process that ESM resolver successfully.

Written by the indexing model from the issue text.