JavaScript 中的大十进制 [英] BigDecimal in JavaScript

问题描述

我对 JavaScript 非常陌生(我来自 Java 背景)，我正在尝试用少量资金进行一些财务计算.

I'm very new to JavaScript (I come from a Java background) and I am trying to do some financial calculations with small amounts of money.

我最初的做法是:

<script type="text/javascript">
    var normBase = ("[price]").replace("$", "");
    var salesBase = ("[saleprice]").replace("$", "");
    var base;
    if (salesBase != 0) {
        base = salesBase;
    } else {
        base = normBase;
    }
    var per5  = (base - (base * 0.05));
    var per7  = (base - (base * 0.07));
    var per10 = (base - (base * 0.10));
    var per15 = (base - (base * 0.15));
    document.write
        (
        '5% Off: $'  + (Math.ceil(per5  * 100) / 100).toFixed(2) + '<br/>' +
        '7% Off: $'  + (Math.ceil(per7  * 100) / 100).toFixed(2) + '<br/>' +
        '10% Off: $' + (Math.ceil(per10 * 100) / 100).toFixed(2) + '<br/>' +
        '15% Off: $' + (Math.ceil(per15 * 100) / 100).toFixed(2) + '<br/>'
    );
</script>

这很好用，只是它总是四舍五入(Math.ceil).Math.floor 也有同样的问题，Math.round 也不适合浮点数.

This worked well except it always rounded up (Math.ceil). Math.floor has the same issue, and Math.round is also no good for floats.

在 Java 中，我会从一开始就完全避免使用浮点数，但是在 JavaScript 中似乎没有默认包含类似的东西.

In Java, I would have avoided the use of floats completely from the get-go, however in JavaScript there does not seem to be a default inclusion of something comparable.

问题是，所有提到的库要么已损坏，要么用于不同的目的.jsfromhell.com/classes/bignumber 库非常接近我的需要，但是我在舍入和精度方面遇到了奇怪的问题......无论我将 Round Type 设置为什么，它似乎是自己决定的.因此，例如，精度为 2 且圆形类型为 ROUND_HALF_UP 的 3.7107 在应该为 3.71 时以某种方式以 3.72 结束.

The problem is, all the libraries mentioned are either broken or for a different purpose. The jsfromhell.com/classes/bignumber library is very close to what I need, however I'm having bizarre issues with its rounding and precision... No matter what I set the Round Type to, it seems to decide on its own. So for example, 3.7107 with precision of 2 and round type of ROUND_HALF_UP somehow winds up as 3.72 when it should be 3.71.

我还尝试了@JasonSmith BigDecimal 库(来自 Java 的 BigDecimal 的机加工端口)，但它似乎适用于我无法运行的 node.js.

I also tried @JasonSmith BigDecimal library (a machined port from Java's BigDecimal), but it seems to be for node.js which I don't have the option of running.

我如何使用 vanilla JavaScript(并且可靠)来实现这一点，或者是否有一个现代的(上面提到的那些现在都老了)我可以使用的库得到维护并且没有损坏?

How can I accomplish this using vanilla JavaScript (and be reliable) or is there a modern (ones mentioned above are all years old now) library that I can use that is maintained and is not broken?

推荐答案

我喜欢使用 accounting.js 来格式化数字、货币和货币.

I like using accounting.js for number, money and currency formatting.

主页 - https://openexchangerates.github.io/accounting.js/

Github - https://github.com/openexchangerates/accounting.js

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