Angular2实现管道根据所选属性对数组对象进行排序

Question

我有一系列产品：

public sort_criteria: any='';
public products: any = [
{title: 'Product_1', desc: 'Lorem Ipsum is simply dummy text of the printing and typesetting industry', img: '../assets/prod_1.jpg', property_1: 50, property_2: 6, property_3: 0, property_4: 76, property_5: 54, property_6: 87, property_7: 0},
{title: 'Product_2', desc: 'Lorem Ipsum has been the industrys standard dummy text ever since the 1500s', img: '../assets/prod_2.jpg', property_1: 0, property_2: 0, property_3: 65, property_4: 0, property_5: 0, property_6: 7, property_7: 88},
{title: 'Product_3', desc: 'It has survived not only five centuries but also the leap into electronic typesetting', img: '../assets/prod_3.jpg', property_1: 0, property_2: 97, property_3: 0, property_4: 56, property_5: 0, property_6: 0, property_7: 86},
{title: 'Product_4', desc: ' It was popularised in the 1960s with the release of Letraset sheets containing,', img: '../assets/prod_4.jpg', property_1: 90, property_2: 25, property_3: 56, property_4: 64, property_5: 0, property_6: 98, property_7: 0},
]
public sort_according_to: any=['Product 1', 'Product 2', 'Product 3', 'Product 4']
setSortCriteria(criteria){
    switch (criteria) {
        case "Product 1":
        alert(3)
        break;
        case "Product 2":
        alert(2)
        break;
        case "Product 3":
        alert(3)
        break;
        case "Product 4":
        alert(4)
        break;      
        default:
        break;
    }
}

我的用户将从7个属性中选择其中一个属性，他选择的任何属性都应在该属性的降序中对我的产品进行排序，即如果他选择属性1，那么我的产品序列将为4,1,2，3。

我的html：

  <h5>Sort products according to the popularity of</h5>
  <div *ngFor="let product of sort_according_to">
    <mdl-radio name="productgroup" [value]='product' [(ngModel)]="sort_criteria" (change)="setSortCriteria(product)"> {{product}} </mdl-radio>
  </div>

  <mdl-card *ngFor="let product of products" class="demo-card-square" mdl-shadow="2">
    <figure class="mdl-card__media">
      <img src="{{product.img}}" alt="" />
    </figure>
    <mdl-card-title mdl-card-expand>
      <h2 mdl-card-title-text>{{product.title}}</h2><br>
    </mdl-card-title>
    <mdl-card-supporting-text>
      {{product.desc}}
    </mdl-card-supporting-text>
    <mdl-card-actions mdl-card-border>
      <button mdl-button mdl-colored mdl-ripple (click)="openProductDetails()">
        view
      </button>
      <div class="mdl-layout-spacer"></div>
      <button class="mdl-button mdl-button--icon mdl-button--colored" (click)="addToCart(product)"><i class="material-icons">shopping_cart</i></button>
    </mdl-card-actions>
  </mdl-card>

在这种情况下如何实现管道？

Answer 1

您可以传递数组＆amp;将分类属性分为管道。然后，管道可以通过该属性对数组进行排序。

// component.html
<mdl-card *ngFor="let product of products | sortArrayByProperty : sort_criteria">
</mdl-card>
//pipe.ts
@Pipe({
    name: 'sortArrayByProperty'
})
export class SortArrayByPropertyPipe implements PipeTransform {
    transform(arr: any[]: property: string): any[] {
        // basic sort by property method
        return arr.sort((a, b) => b[property] - a[property]);
    }
}

这是一个基本工作plnkr https://plnkr.co/edit/xgzkljalx2cehwlsgots?p=preview