Angular2/JavaScript-按1递增/递减(点击) [英] Angular2/JavaScript - Increment/Decrement by 1 on (click)

问题描述

我想在用户按下添加按钮时增加/减少，然后相应地更新金额值.我尝试了几次，但不幸的是我没有成功！

I want to Increment/Decrement when the user presses the add button, then update the amount value accordingly. I've tried a couple of times, but unfortunately I was not successful!

这是代码:

  addToCart(){
  this.amount = 1;
  }

  addItem(){
    this.amount++;
    console.log('plus is : '+this.amount++)
  }

  removeItem(){
   this.amount--;
   console.log('plus is : '+this.amount--)
  }

HTML:

   <div (click)="addToCart()">ADD</div>
   <div (click)="removeItem()" class="btnSign">-</div> 
   <div>{{amount}}</div> 
   <div (click)="addItem()" class="btnSign">+</div>

推荐答案

错误在于使用++

export class HelloWorld {
public amount:number;

addToCart(){
this.amount = 1;
}

addItem(){
this.amount=this.amount+1;
console.log('plus is : '+this.amount)
}

removeItem(){
this.amount=this.amount-1;
console.log('plus is : '+this.amount)
}


}

这里是矮人

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