如何使用* ngFor迭代对象键?

问题描述

我一直在研究，发现可以使用以下代码对对象使用* ngFor:

I've been digging around, and found out that I can use the following to use *ngFor over an object:

 <div *ngFor="#obj of objs | ObjNgFor">...</div>

其中ObjNgFor管道为:

@Pipe({ name: 'ObjNgFor',  pure: false })
export class ObjNgFor implements PipeTransform {
    transform(value: any, args: any[] = null): any {
        return Object.keys(value).map(key => value[key]);
    }
}

但是，当我有一个这样的对象时:

However, when I have an object like this:

{
"propertyA":{
    "description":"this is the propertyA",
    "default":"sth"
 },
"propertyB":{
    "description":"this is the propertyB",
    "default":"sth"
 }
}

我不太确定如何提取"propertyA"和"propertyB"，以便可以从* ngFor指令访问它们.有什么想法吗?

I am not quite sure how I can extract 'propertyA' and 'propertyB', so that it is accessible from the *ngFor directive. Any ideas?

更新

我想做的是呈现以下HTML:

What I want to do, is to present the following HTML:

        <div *ngFor="#obj of objs | ObjNgFor" class="parameters-container">
            <div class="parameter-desc">
                {{SOMETHING}}:{{obj.description}}
            </div>
        </div>

等于propertyA和propertyB的地方(这就是对象的结构).因此，这将导致:

Where something would be equal to propertyA and propertyB (this is how the object is structured). So, this would lead to:

propertyA:this is the propertyA
propertyB:this is the propertyB

推荐答案

更新

在 6.1.0-beta.1 中引入了KeyValuePipe https://github.com/angular/angular/pull/24319

<div *ngFor="let item of {'b': 1, 'a': 1} | keyvalue">
  {{ item.key }} - {{ item.value }}
</div>

柱塞示例

Plunker Example

以前的版本

您可以尝试这样的事情

export class ObjNgFor implements PipeTransform {
    transform(value: any, args: any[] = null): any {
        return Object.keys(value).map(key => Object.assign({ key }, value[key]));
    }
}

然后在您的模板上

  <div *ngFor="let obj of objs | ObjNgFor">
   {{obj.key}} - {{obj.description}}
  </div>

柱塞

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