a for the model of the class hierarchy
    var nodeDataArray = [];

    // Iterate over all of the classes in "go"
    for (const k in go) {
      var cls = go[k];
      // ignore enums and other stuff
      if (typeof cls !== 'function') continue;
      // find base class constructor
      const base = Object.getPrototypeOf(cls);
      if (base === Object) {
        // "root" node?
        nodeDataArray.push({ key: k });
      } else if (typeof base === 'function') {
        // add a node for this class an