How to use the @uifabric/example-app-base/lib/index.extractAnchorLink function in @uifabric/example-app-base

private _handleRouteChange = (): void => {
    const { pagePath: prevPagePath, platform } = this.state;
    const { siteDefinition } = this.props;
    const { platforms } = siteDefinition;

    const newPagePath = removeAnchorLink(location.hash);
    if (prevPagePath === newPagePath) {
      // Must have been a change to the anchor only (not the route).
      // Don't do a full update, just jump to the anchor.
      this._jumpToAnchor(extractAnchorLink(location.hash));
      return;
    }

    const platformKeys = platforms && (Object.keys(platforms) as TPlatforms[]);
    if (platformKeys && platformKeys.length > 0) {
      // Test if the platform has changed on each hashchange to avoid costly forEach below.
      const currentPlatformRegex = new RegExp(`/${platform}\\b`);

      if (!currentPlatformRegex.test(newPagePath)) {
        for (const key of platformKeys) {
          // If the user navigates directly to a platform specific page, set the active platform to that of the new page.
          const isNewPlatform = new RegExp(`/${key}`, 'gi');
          if (isNewPlatform.test(newPagePath)) {
            this._onPlatformChanged(key);
            break;
          }

public componentDidUpdate(prevProps: ISiteProps, prevState: ISiteState): void {
    if (prevState.pagePath !== this.state.pagePath) {
      this._jumpToAnchor(extractAnchorLink(location.hash));
    }

    const { activePages, pagePlatforms } = this.state;
    const { siteDefinition } = this.props;

    // If current page doesn't have pages for the active platform, switch to its first platform.
    if (Object.keys(pagePlatforms).length > 0 && activePages.length === 0) {
      const firstPlatform = getPageFirstPlatform(getSiteArea(siteDefinition.pages), siteDefinition);
      this._onPlatformChanged(firstPlatform);
    }
  }