相关疑难解决方法(0)

这是我的异步验证器它没有去抖时间,我该如何添加它？

static emailExist(_signupService:SignupService) {
  return (control:Control) => {
    return new Promise((resolve, reject) => {
      _signupService.checkEmail(control.value)
        .subscribe(
          data => {
            if (data.response.available == true) {
              resolve(null);
            } else {
              resolve({emailExist: true});
            }
          },
          err => {
            resolve({emailExist: true});
          })
      })
    }
}