如何使数字具有正确的逗号格式并且每次在 Javascript 中都精确到 2 位小数？ [复制]答案

【问题标题】：How to make a number have proper comma formatting AND round to exactly 2 decimals every time in Javascript? [duplicate]如何使数字具有正确的逗号格式并且每次在 Javascript 中都精确到 2 位小数？ [复制]
【发布时间】：2021-03-12 02:27:33
【问题描述】：

我正在制作货币转换器，我希望结果具有正确的逗号格式以及始终四舍五入到两位小数。

例如，如果我的号码是 1000000.3，我希望结果是 1,000,000.30。

我有什么遗漏的吗？我对编码非常陌生，因此我们将不胜感激！

编辑：没有看到堆栈溢出提供了运行代码的选项，因此您可以将其复制并粘贴到代码编辑器中或在此处打开代码：https://xrpalerts.000webhostapp.com/testing.html

<!DOCTYPE html>
<html>
<body>

<script>

var CalculatorResult = 1000000.3

var CalculatorResultLocale = parseFloat(CalculatorResult).toLocaleString("us-EN");
var CalculatorResultLocaleFixed = parseFloat(CalculatorResultLocale).toFixed(2);

var CalculatorResultFixed = parseFloat(CalculatorResult).toFixed(2);
var CalculatorResultFixedLocale = parseFloat(CalculatorResultFixed).toLocaleString("us-EN");


function ClickAllResults() {

    document.write("CalculatorResultLocale: ");
    document.write(CalculatorResultLocale);
    document.write("<br>");

    document.write("CalculatorResultLocaleFixed: ");
    document.write(CalculatorResultLocaleFixed);
    document.write("<br>");
    document.write("<br>");

    document.write("CalculatorResultFixed: ");
    document.write(CalculatorResultFixed);
    document.write("<br>");

    document.write("CalculatorResultFixedLocale: ");
    document.write(CalculatorResultFixedLocale);
    document.write("<br>");
}
</script>

<button onclick="ClickAllResults()" id = "button"><strong>Click to see all results</strong></button>

</body>
</html>

【问题讨论】：

num.toLocaleString(undefined, { minimumFractionDigits: 2, maximumFractionDigits: 2 }) 来自重复的How to use toLocaleString() and tofixed(2) in JavaScript

标签： javascript currency cryptocurrency money-format

【解决方案1】：

要按小数位显示 toLocaleString，请使用

.toLocaleString("us-EN", { minimumFractionDigits: 2, maximumFractionDigits: 2 })

你的代码会是这样的

var CalculatorResultFixedLocale = parseFloat(CalculatorResultFixed).toLocaleString("us-EN", { minimumFractionDigits: 2, maximumFractionDigits: 2 });

【讨论】：

【解决方案2】：

<!DOCTYPE html>
<html>
<body>

<script>

var CalculatorResult = 1000000.3
var CalculatorResultMoney = currencyFormat(CalculatorResult);

function ClickAllResults() {
    document.write("CalculatorResultMoney: ");
    document.write(CalculatorResultMoney);
    document.write("<br>");
}

function currencyFormat(num) {
  let a = '$' + num.toFixed(2).replace(/(\d)(?=(\d{3})+(?!\d))/g, '$1,')
  return a;
}
</script>

<button onclick="ClickAllResults()" id = "button"><strong>Click to see all results</strong></button>

</body>
</html>

我确实找到了与您的要求类似的功能 https://blog.abelotech.com/posts/number-currency-formatting-javascript/

function currencyFormat(num) {
  let a = '$' + num.toFixed(2).replace(/(\d)(?=(\d{3})+(?!\d))/g, '$1,')
  return a;
}

【讨论】：

【解决方案3】：

function numberWithCommas(x) {
    return x.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ",");
}

const round = (value, decimals) => {
  return numberWithCommas(Number(Math.round(value + 'e' + decimals) + 'e-' + decimals).toFixed(2));
};

console.log(round(84347.336, 2)); // 84,347.34 
console.log(round(8557.332, 2)); // 8,557.33 
console.log(round(187, 2)); // 187.00

toFixed() 方法使用定点表示法格式化数字。

【讨论】：

对不起，错过了那部分，现在我更新了答案@Ouroborus，请检查

【解决方案4】：

//execute below function

CommaFormatted('2345643.123')

//result => 2,345,643.123

function CommaFormatted(amount) {
    var delimiter = ","; // replace comma if desired
    var a = amount.split('.',2)
    var d = a[1];
    var i = parseInt(a[0]);
    if(isNaN(i)) { return ''; }
    var minus = '';
    if(i < 0) { minus = '-'; }
    i = Math.abs(i);
    var n = new String(i);
    var a = [];
    while(n.length > 3) {
        var nn = n.substr(n.length-3);
        a.unshift(nn);
        n = n.substr(0,n.length-3);
    }
    if(n.length > 0) { a.unshift(n); }
    n = a.join(delimiter);
    if(d.length < 1) { amount = n; }
    else { amount = n + '.' + d; }
    amount = minus + amount;
    return amount;
}

请参考 CSS 技巧文章https://css-tricks.com/snippets/javascript/comma-values-in-numbers/#:~:text=Javascript%20has%20a%20method%20called,will%20convert%20it%20to%2012%2C345%2C678.90。

【讨论】：