angular 7 HTTP请求动态表单不起作用

Question

Reactive Form angular 7创建一个动态表单生成器，就像在.ts中使用JSON可以正常工作的链接一样，但是无法从HTTP请求中获取JSON。 https://stackblitz.com/edit/angular-wn34ld，但我从服务器获得的JSON响应

{
    "Description": "Transformer Mapping",
    "data": [
        {
            "name": "//Document",
            "options": [
                "InstructingAgentMmbId",
                "InstructingAgentName"
            ],
            "type": "select",
            "value": ""
        },
        {
            "name": "//DocumentLC",
            "label": "List",
            "type": "checkbox",
            "value": "false"
        }
 ],
    "rescode": "0000",
    "status": "Success",
    "timestamp": "2019-06-18 20:06:44.168"
}

因此根据响应，我更改了接口模型和HTTP服务，但显示了错误

  

FormGroup需要一个FormGroup实例。请通过

regConfig:FieldConfig[];
export interface test {
  data?: FieldConfig[];

}
this.http.post<test>('http://155.54.54.45:8080/Auto/transform/mapping', request).subscribe(res => {

  this.regConfig =res.data;
  console.log(this.regConfig)
});