SP.Social.SocialPostCreationData.definitionData property (sp.userprofiles)
This member is reserved for internal use and is not intended to be used directly from your code.
Applies to: apps for SharePoint | Office 365 | SharePoint Foundation 2013 | SharePoint Server 2013
var value = SP.Social.SocialPostCreationData.get_definitionData()
SP.Social.SocialPostCreationData.set_definitionData(value)