Angularjs 嵌套数组迭代的角度7*Ng

在Angular 7中，我有嵌套的对象数组，如下所示进行迭代。使用*ngFor的第一级迭代确实有效，但嵌套迭代不会显示任何值。有人帮我做什么吗？找到下面的代码

示例JSON

const res=[{
2: [ 
{id:1，cId:2，名称：'test1'}，{id:2，cId:2，名称：'test2'}
],
8: [ 
{id:10，cId:8，名称：'test10'}
]
}]
{{country.key}
{{airport.name}

使用以下内容更改html

<div *ngFor="let country of res[0] | keyvalue;">
   <span> {{country.key}} </span> <!-- Displayed 2 and 8 -->
   <div *ngFor="let airport of country.value">
         <span>{{airport.name}}</span> <!-- name should be displayed, but nothing is coming up-->
   </div>
</div>

{{country.key}
{{airport.name}

更具体地说，您必须用country.value替换country[country.key]

<div *ngFor="let country of res[0] | keyvalue;">
   <span> {{country.key}} </span> <!-- Displayed 2 and 8 -->
   <div *ngFor="let airport of country.value">
         <span>{{airport.name}}</span> <!-- name should be displayed, but nothing is coming up-->
   </div>
</div>