getNode (viewArray) {
    let currentGraph = this.getGraph(this.rootGraphName);
    let node;
    every(viewArray, (nodeName, index) => {
      const nextNode = currentGraph.getNode(nodeName);
      if (nextNode) {
        if (index === viewArray.length - 1) {
          node = nextNode;
          return false;
        }
        const nextGraph = currentGraph.graphs[nodeName];
        if (nextGraph) {
          currentGraph = nextGraph;
          return true;
        }
      }
      return false;
    });
    return node;
  }
Get a specific node object

@param {array} viewArray e.g. [ node1, node2 ]