code: function addNodeOrPathListenerApi( eventId, jsonPathOrListenerMap, callback ){
  
      if( isString(jsonPathOrListenerMap) ) {
        addSingleNodeOrPathListener(eventId, jsonPathOrListenerMap, callback);
  
      } else {
        addMultipleNodeOrPathListeners(eventId, jsonPathOrListenerMap);
      }
  
      return oboeApi; // chaining
    }
docs: implementation behind .onPath() and .onNode()