message: Adding a important missing line
  Fix the unexpected performance of the navigation bar.
diff: @@ -14,6 +14,7 @@ export class AppComponent {
  // control nav style by changing the class name
  isAtHome() {
  if (this.router.url === '/' || this.router.url === '/#!') {
  + return 'at-home';
  } else {
  return 'off-home';
  }
  