borisyankov/DefinitelyTyped — pull request #3137 by allanhvam (2014-11-13 12:01:22+00:00)
Title: useAnimation made optional in Callout

useAnimation should be optional in Callout close and open. I couldn't find any official documentation on this, but SharePoint defaults to false if it is not set:

this.close = function(useAnimation) {
useAnimation = m$.isBoolean(useAnimation) ? useAnimation : false;

Examples online also shows that this argument should be optional:
http://blog.alexboev.com/2012/08/custom-callouts-in-sharepoint-2013_21.html