How to use the @uifabric/example-app-base/lib/index2.hasActiveChild function in @uifabric/example-app-base

linkText = (
          <>
            {before}
            {highlightMatch}
            {after}
          
        );
      }
    }

    return (
      <li>
        {!(page.isUhfLink &amp;&amp; location.hostname !== 'localhost') &amp;&amp; searchRegEx.test(page.title) &amp;&amp; (
          
            {linkText}
            {page.isExternal &amp;&amp; }
          
        )}</li>

private _renderSection = (page: INavPage, sectionIndex: number) => {
    if (page.isCategory && page.pages && this._hasMatchChild(page)) {
      const key = `${page.title}-${sectionIndex}`;
      return (
        <li>
          
            {this._renderLinkList(page.pages, false)}
          
        </li>
      );
    }
  };

private _renderSection = (page: INavPage, sectionIndex: number) => {
    if (page.isCategory && page.pages && this._hasMatchChild(page)) {
      const key = `${page.title}-${sectionIndex}`;
      return (
        <li>
          
            {this._renderLinkList(page.pages, false)}
          
        </li>
      );
    }
  };

      .filter(page => !page.isHiddenFromMainNav && hasActiveChild(page, platform))
      .forEach(page => {