[Bug] Class extends value undefined is not a constructor or null

[celluj34]

Hello;

I'm using webpack + typescript to compile my app, but I'm getting an error when building for production. Everything works in development mode. There error I'm getting is Uncaught TypeError: Class extends value undefined is not a constructor or null. Do you have any idea what's going on, or have you seen that before?

[celluj34]

I found it's an issue with overriding a custom abstract base class. Once I inherit directly from Validation, it works as expected.