toFixed() 方法工作不在 javascript 中的 number() 方法内？

Question

What I want: after calculation result should be in 2 decimal format.

here's my code

let totalNetWeightLocal = 0;

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

Problem: calculation is working but toFixed() isn't working. I'm getting results in more than 2 decimal values.

Can someone please help me?

Answer 1

The problem with your code is, that the .toFixed(2) is at the wrong position

What your code does is something like

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

Which means, you add two strings together like 0 + '10.24' which will be 010.24 . What you need to do is:

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

Considering, you might have a list of items you can write a functions as follows:

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

Try this code. Your code's working fine.

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?