减去数量基于id

问题描述

实际上我想根据id减去数量。当用户单击'A'上的按钮时，只需将'A'的数量减少1。 此演示代码stackblitz

HTML

<p *ngFor="let item of arrayOfArray"> 
  Name: {{item.name}} Quantity: {{item.quantity - currentIndex}} <button (click)="addItem(item)">minus Quantity</button>
</p>

组件

public currentIndex = 0;
  arrayOfArray = [
    {id: '1',name: 'A',quantity: '12'},{id: '2',name: 'B',quantity: '29'},{id: '3',name: 'C',quantity: '21'},{id: '4',name: 'D',quantity: '11'}
  ]

  addItem(val){
    if(val.id){
      this.currentIndex += 1;
    }
  }

解决方法

您做错了。检查this demo code

用于html

<p *ngFor="let item of arrayOfArray"> 
  Name: {{item.name}} Quantity: {{item.quantity}}
  <button (click)="minusItem(item)">minus Quantity</button>
</p>

  minusItem(val){
    if(val.id){
      for (let ele of this.arrayOfArray) {
         if (ele.id === val.id){
          ele.quantity--;
          break
        }
      }
    }
  }