mbostock/d3 — pull request #1539 by carlsverre (2013-09-23 17:26:20+00:00)
Title: Zoom behavior: Enable/disable mouse-wheel zoom at runtime

I was looking for an easy way to add the ability to only zoom when a meta-key was pressed, and it looked like this patch was one of the easiest ways to achieve it. I am using it in my app right now, and it works perfectly.

Hope that it can help someone else.