Error: Line 2: Unexpected reserved word

The module defines a class. Is that the problem?

It shouldn't be at all - unfortunately the minifier its showing its age now. It might be time to ditch Esprima completely and move to the closure compiler (there's an open PR on GitHub that adds an offline version of closure - it's just quite a bit of code to include!).

It would have been nice if the error message included a bit more information

Just done - next IDE update should have it in :)