错误TypeError：无法读取Angular中未定义的属性“ get”

Question

我有以下代码，我想从后端发送的标头参数X-OBSERVATORY-AUTH中获取令牌。我收到以下错误： 错误TypeError：无法读取未定义的属性“ get”。我该怎么办？

login( username: string,  password: string) {
  var user: User = {  username: username, password: password };
this.http
  .post<any>(
    "http://localhost:3000/api/auth",user)
  .subscribe((response: Response) => {
    const token = response.headers.get('X-OBSERVATORY-AUTH');
    this.token = token;
    if (token) {
      this.isAuthenticated = true;
   //   this.userId = response.body._id;
     // this.isAdmin=response.body.isAdmin;
      this.authStatusListener.next(true);
      this.saveAuthData(token, this.userId, this.isAdmin); 
    }
  });
}