Possible typo in README

[Ondrej Sevcik]

Hello,

this is from the README

Internally, the drag behavior uses selection.on to bind the necessary event listeners for dragging. The listeners use the name .drag, so you can subsequently unbind the drag behavior as follows:

selection.on(".drag", null);  <--- should the event name contain dot? 

although I'm no expert on d3, this looks like a typo.

[Mike Bostock]

This is not a typo. Please see the documentation for selection.on and drag for explanation.

[Ondrej Sevcik]

thanks for the explanation 👍