This extension is not compatible with the jsonp result that is returned by ExpressJS in NodeJS.
Express returns the following syntax:

/**/ typeof callback === 'function' && callback( ... );

As the source code documents, the /**/ is a specific security mitigation for "Rosetta Flash JSONP abuse". The typeof is for error checking.

I looked at the source but couldn't find an easy solution for PR. I hope you can fix this to make this extension even more useful.