documentcloud/backbone — pull request #1890 by braddunbar (2012-12-10 16:24:27+00:00)
Title: Implement once with minimal change to other Events methods.

This version is a bit larger, but I think the cost in bytes is more than offset by minimizing change to the other methods. `on` and `trigger` are unchanged, and `off` provides one small concession for removing handlers with a callback reference.