SP.Social.SocialActor.isFollowed property (sp.userprofiles)
Gets a value that indicates whether the current user is being followed.
Applies to: apps for SharePoint | Office 365 | SharePoint Foundation 2013 | SharePoint Server 2013
var value = SP.Social.SocialActor.get_isFollowed()
true if the current user is being followed; otherwise false.
The isFollowed property is valid only when actorType is a user.