JavaScript中的货币数学 [英] Currency Math in JavaScript

问题描述

有人可以帮我解决这个算术问题的JavaScript / jQuery解决方案：

Can someone please help me out with a JavaScript/jQuery solution for this arithmetic problem:

我需要从另一个中减去一个数字。

I need to subtract one number from the other.

问题是数字有一个美元符号（因为它的钱），因此jQuery将它们视为字符串而不是数字。

The problem is that the numbers have a dollar sign (because its money), therefore jQuery is treating them as strings instead of numbers.

我创建了两个变量 - toalAssets 和 totalLiabilites 。我想从前者中减去后者并将结果放入另一个名为 netWorth 的变量中。

I have created two variables - toalAssets and totalLiabilites. I would like to subtract the latter from the former and place the result into another variable called netWorth.

也许我需要使用 parseFloat（）？

但我不知道怎么回事 - 这一切都在我头上！

But I'm not sure how - This is all a little over my head!

推荐答案

var totalLiabilites = '$52.34';
var toalAssets      = '$85.12';
var pattern         = /[^0-9.-]+/g;

var result = parseFloat(toalAssets.replace(pattern, '')) -
             parseFloat(totalLiabilites.replace(pattern, ''));

// result: 32.78

注意：在JavaScript中，建议 ¹ 将货币处理为表示分数（8512而不是85.12）的整数。这是为了避免浮点运算的问题。 0.1 + 0.2 == 0.3 在JavaScript中返回false，但幸运的是浮点中的整数运算是精确的，因此可以通过缩放来避免十进制表示错误。

Note: In JavaScript it is recommended¹ to handle money as an integer representing the number of cents (8512 instead of 85.12). This is to avoid problems with floating-point arithmetic. 0.1 + 0.2 == 0.3 returns false in JavaScript, but fortunately integer arithmetic in floating point is exact, so decimal representation errors can be avoided by scaling.

您可能需要查看以下帖子以进一步阅读此主题： JavaScript的数学是否被破坏？

You may want to check the following post for further reading on this topic: Is JavaScript’s math broken?

当值被渲染到浏览器时，您始终可以应用货币符号格式。

You can always apply the currency-sign formatting when the values are rendered to the browser.

¹ _{Douglas Crockford： JavaScript：好的部件：附录A - 可怕的部件（第105页）。}

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