An API I was calling into was returning empty objects in addition to null. I made this helper function to simplify the handling logic.

isNullOrEmpty.as

public static function isNullOrEmpty(object:Object):Boolean
{
	if (!object)
		return true;
		
	if (object is Array ||
		object is IList)
		return !object.length;
	
	for (var key:String in object)
		return false;
	
	return true;
}