findNodes (searchString) {
    if (this.currentGraph) {
      this.disableHoverInteractions = !!searchString;
      // If !!searchString, clear any highlighted object
      if (this.disableHoverInteractions && this.currentGraph.highlightedObject) {
        this.currentGraph.highlightObject();
      }

      // if !searchString and highlighted object, do nothing
      if (searchString || !this.currentGraph.highlightedObject) {
        // Highlight matches
        const matchesFound = this.currentGraph.highlightMatchedNodes(searchString);
        matchesFound.total = this.currentGraph.nodeCounts.total;
        matchesFound.visible = this.currentGraph.nodeCounts.visible;

        this.emit('matchesFound', matchesFound);
        return matchesFound;
      }
    }
    return undefined;
  }
Highlight nodes that match searchString.  Searches the node name and the list
of sub nodes, if nodes have one.

@param {string} searchString The string to match against the nodes.

@returns {object} { total, totalMatches, visible, visibleMatches }