rollbar/rollbar.js — pull request #50 by BinaryMuse (2014-10-03 17:51:56+00:00)
Title: Don't choke on null callbacks in removeEventListener

We're seeing situations where third-party libraries are mistakenly passing `null` as the second parameter to `removeEventListener`. Since Rollbar tries to access `._wrapped` on the argument, we get exceptions from inside the overwritten method.

This PR implements a check to ensure that the value is truthy before trying to access the `._wrapped` property.