根据 id 减去数量

Question

实际上我想根据 id 减去数量。当用户单击“A”上的按钮时，“A”的数量应该减少 1。此演示代码stackblitzHTML<p *ngFor="let item of arrayOfArray">   Name: {{item.name}} Quantity: {{item.quantity - currentIndex}} <button (click)="addItem(item)">minus Quantity</button></p>成分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;    }  }

Answer 1

你做错了 。检查这个演示代码

对于 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

        }

      }

    }

  }