addNode does not correctly add non-root nodes about he-tree HOT 4 CLOSED

export function depthFirstSearch(
  obj: object | any[],
  [...]
) {
  const rootChildren = isArray(obj) ? obj : [obj]; // <-- assumes that the given object is root
  [...]
  try {
    func(rootChildren, null /* <-- assumes parent is null */, isArray(obj) ? [] : null);
  } [...]
}

      const node = {
        categoryId: this.nextCategoryId(),
        name,
        parentId: parent.categoryId,
      };
      draggable.addNode(node, parent.categoryId);
      console.log("node after add: ", node);
      (node as any).$level = (parent as any).$level + 1;
      console.log("node after fix: ", node);