toFixed() 方法不在 javascript 中的 number() 方法内？

Question

我要的是：计算后的结果应该是2位小数。

这是我的代码

let totalNetWeightLocal = 0;

totalNetWeightLocal = totalNetWeightLocal + Number((parseFloat(item.netWeight) * parseInt(item.quantity)).toFixed(2));

问题： 计算正常但 toFixed() 不工作。我得到的结果超过 2 个小数。

有人可以帮帮我吗？

Answer 1

您的代码存在问题，.toFixed(2) 位置错误

您的代码所做的类似于

const fullWeight = parseFloat(item.netWeight) * parseInt(item.quantity)
totalNetWeightLocal = totalNetWeightLocal + fullWeight.toFixed(2));

这意味着，您将两个字符串加在一起，例如 0 + '10.24'，这将是 010.24。您需要做的是：

// you don’t need Number() here:
const itemWeight = parseFloat(item.netWeight) * parseInt(item.quantity)
totalNetWeightLocal += itemWeight;
totalNetWeightLocal.toFixed(2);

考虑到，您可能有一个项目列表，您可以编写如下函数：

const items = [
  { netWeight: '4.53', quantity: '3' },
  { netWeight: '20.33', quantity: '10' }
];

const getTotalNetWeightLoal = items => {
  const totalNetWeightLocal = items.reduce(
    (weight, { netWeight, quantity }) =>
      weight + parseFloat(netWeight) * parseInt(quantity),
    0
  );

  return totalNetWeightLocal.toFixed(2);
};

console.log(getTotalNetWeightLoal(items));

Answer 2

试试这个代码。您的代码工作正常。

let item = { "netWeight": "5.99498", "quantity": '8' }
    let totalNetWeightLocal = 0;
    totalNetWeightLocal = totalNetWeightLocal + Number((parseFloat(item.netWeight) * parseInt(item.quantity)).toFixed(2));
    console.log(totalNetWeightLocal) // output: 47.96

//Can you provide cases where it failed?

toFixed() 方法不在 javascript 中的 number() 方法内？

toFixed() method working isn't inside number() method in javascript?

javascript

tofixed