addNode(node) {
    // add it to the list and map
    this._nodeMap[node.getId()] = node;
    // update last update time stamp
    this._touchLastUpdate();
  }
/**
   * Add a new node to the graph.
   * @param {Node} node - expect a Node object to be added to the graph.
   */
Add a new node to the graph.
@param {Node} node - expect a Node object to be added to the graph.
Add a new node to the graph . @param { Node } node - expect a Node object to be added to the graph .
addNode(node) {
    this._nodeMap[node.getId()] = node;
    this._touchLastUpdate();
  }
addNode ( node ) { this . _nodeMap [ node . getId ( ) ] = node ; this . _touchLastUpdate ( ) ; }
Add a new node to the graph.
Add a new node to the graph .
// add it to the list and map // update last update time stamp