angular *ngIf 判断对象数组是否为空

判断对象

  "downloadinfo": [
    {
      "downtype": "16",
      "linkvalue": "https://pan.baidu.com/s/1kVutjX9",
      "fetchcode": "",
      "remark": "",
      "ico": "http://i1.fuimg.com/588755/7dcc4108ce360c2a.png"
    }
  ]

模板代码

<div *ngIf="isEmptyObject(downloadinfo); else templateName">downloadinfo不为空</div>
<ng-template #templateName>downloadinfo为空</ng-template>

组建代码

public isEmptyObject(obj) {
      //console.log(obj.length);
      return obj.length;
}