TypeError：无法在$$ AnimateCssDriverProvider。$ get中读取属性“包含”为null。

Question

我正在运行带有gulp的angular js项目，并且在访问localhost：3000时遇到错误TypeError：无法读取附近angular-animate.js中$$AnimateCssDriverProvider.$get处的null的'包含'属性。

var bodyNode = $document[0].body;
    var rootNode = getDomNode($rootElement);

var rootBodyElement = jqLite(
  // this is to avoid using something that exists outside of the body
  // we also special case the doc fragment case because our unit test code
  // appends the $rootElement to the body after the app has been bootstrapped
  isDocumentFragment(rootNode) || bodyNode.contains(rootNode) ? rootNode : bodyNode
);

为什么会出现此错误？