Removing icon when there are no children

I’m building a TreeView with the Treeview component from Material UI: https://material-ui.com/components/tree-view/

I have created the component below which fetches data when a node is expanded. Furthermore, the tree is build so each node that have children also is a tree of MyTreeItem, but I have one question:

When I reach a point where there are no more children, I want to remove/hide the expand/collapse icon. How can i achieve this?

import ReactDOM from "react-dom";
import React from "react";
import TreeView from "@material-ui/lab/TreeView";
import ExpandMoreIcon from "@material-ui/icons/ExpandMore";
import ChevronRightIcon from "@material-ui/icons/ChevronRight";
import TreeItem from "@material-ui/lab/TreeItem";
const { useState, useCallback } = React;

export default function MyTreeItem(props) {
  const [childNodes, setChildNodes] = useState(null);
  const [expanded, setExpanded] = React.useState([]);

  function fetchChildNodes(id) {
    return new Promise(resolve => {
      setTimeout(() => {
        resolve({
          children: [
            {
              id: "2",
              name: "Calendar"
            },
            {
              id: "3",
              name: "Settings"
            },
            {
              id: "4",
              name: "Music"
            }
          ]
        });
      }, 1000);
    });
  }

  const handleChange = (event, nodes) => {
    const expandingNodes = nodes.filter(x => !expanded.includes(x));
    setExpanded(nodes);
    if (expandingNodes[0]) {
      const childId = expandingNodes[0];
      fetchChildNodes(childId).then(
        result =>
          result.children
            ? setChildNodes(
                result.children.map(node => (
                  <MyTreeItem key={node.uuid} {...node} action={props.action} />
                ))
              )
            : console.log("No children") // How do I remeove the expand/collapse icon?
      );
    }
  };

  return (
    <TreeView
      defaultCollapseIcon={<ExpandMoreIcon />}
      defaultExpandIcon={<ChevronRightIcon />}
      expanded={expanded}
      onNodeToggle={handleChange}
    >
      {/*The node below should act as the root node for now */}
      <TreeItem nodeId={props.id} label={props.name}>
        {childNodes || [<div key="stub" />]}
      </TreeItem>
    </TreeView>
  );
}
const rootElement = document.getElementById("root");
ReactDOM.render(<MyTreeItem id="1" name="Applications" />, rootElement);


Source: ReactJs