如何将数字格式化为货币字符串？ [英] How to format numbers as currency string?

问题描述

我想用JavaScript格式化价格。我想要一个函数，该函数以 float 作为参数，并返回格式如下的 string ：

I would like to format a price in JavaScript. I'd like a function which takes a float as an argument and returns a string formatted like this:

"$ 2,500.00"

执行此操作的最佳方法是什么？

What's the best way to do this?

推荐答案

Number.prototype.toFixed

该解决方案与每个主流浏览器都兼容：

Number.prototype.toFixed

This solution is compatible with every single major browser:

  const profits = 2489.8237;

  profits.toFixed(3) //returns 2489.824 (rounds up)
  profits.toFixed(2) //returns 2489.82
  profits.toFixed(7) //returns 2489.8237000 (pads the decimals)

所有您需要添加的货币符号（例如 $ + Profits.toFixed（2）），您将获得美元金额。

All you need is to add the currency symbol (e.g. "$" + profits.toFixed(2)) and you will have your amount in dollars.

如果需要在每个数字之间使用 ，则可以使用以下功能：

If you require the use of , between each digit, you can use this function:

function formatMoney(number, decPlaces, decSep, thouSep) {
decPlaces = isNaN(decPlaces = Math.abs(decPlaces)) ? 2 : decPlaces,
decSep = typeof decSep === "undefined" ? "." : decSep;
thouSep = typeof thouSep === "undefined" ? "," : thouSep;
var sign = number < 0 ? "-" : "";
var i = String(parseInt(number = Math.abs(Number(number) || 0).toFixed(decPlaces)));
var j = (j = i.length) > 3 ? j % 3 : 0;

return sign +
	(j ? i.substr(0, j) + thouSep : "") +
	i.substr(j).replace(/(\decSep{3})(?=\decSep)/g, "$1" + thouSep) +
	(decPlaces ? decSep + Math.abs(number - i).toFixed(decPlaces).slice(2) : "");
}

document.getElementById("b").addEventListener("click", event => {
  document.getElementById("x").innerText = "Result was: " + formatMoney(document.getElementById("d").value);
});

<label>Insert your amount: <input id="d" type="text" placeholder="Cash amount" /></label>
<br />
<button id="b">Get Output</button>
<p id="x">(press button to get output)</p>

使用像这样：

(123456789.12345).formatMoney(2, ".", ",");

如果您始终要使用'。'和'，'，则可以不使用它们

If you're always going to use '.' and ',', you can leave them off your method call, and the method will default them for you.

(123456789.12345).formatMoney(2);

如果您的文化中两个符号都翻转了（即欧洲人），并且您想使用默认值，只需在 formatMoney 方法中粘贴以下两行即可：

If your culture has the two symbols flipped (i.e. Europeans) and you would like to use the defaults, just paste over the following two lines in the formatMoney method:

    d = d == undefined ? "," : d, 
    t = t == undefined ? "." : t, 

自定义功能（ES6）

如果您可以使用现代ECMAScript语法（即通过Babel），则可以改用以下更简单的函数：

Custom function (ES6)

If you can use modern ECMAScript syntax (i.e. through Babel), you can use this simpler function instead:

function formatMoney(amount, decimalCount = 2, decimal = ".", thousands = ",") {
  try {
    decimalCount = Math.abs(decimalCount);
    decimalCount = isNaN(decimalCount) ? 2 : decimalCount;

    const negativeSign = amount < 0 ? "-" : "";

    let i = parseInt(amount = Math.abs(Number(amount) || 0).toFixed(decimalCount)).toString();
    let j = (i.length > 3) ? i.length % 3 : 0;

    return negativeSign + (j ? i.substr(0, j) + thousands : '') + i.substr(j).replace(/(\d{3})(?=\d)/g, "$1" + thousands) + (decimalCount ? decimal + Math.abs(amount - i).toFixed(decimalCount).slice(2) : "");
  } catch (e) {
    console.log(e)
  }
};
document.getElementById("b").addEventListener("click", event => {
  document.getElementById("x").innerText = "Result was: " + formatMoney(document.getElementById("d").value);
});

<label>Insert your amount: <input id="d" type="text" placeholder="Cash amount" /></label>
<br />
<button id="b">Get Output</button>
<p id="x">(press button to get output)</p>

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