JavaScript支持64位整数吗？ [英] Does JavaScript support 64-bit integers?

问题描述

我想知道JavaScript是否错误处理64位整数还是我做错了什么？

I was wondering if JavaScript is mishandling 64-bit integers or am I doing something wrong?

我有以下代码：

var str = "0x4000000000000000";   //4611686018427387904 decimal
var val = parseInt(str);
alert(val);

我得到这个值：4611686018427388000，即0x4000000000000060

I get this value: "4611686018427388000", which is 0x4000000000000060

推荐答案

JavaScript使用 IEEE-754表示数字双精度（64位）格式。据我所知，这给你53位精度，或十五到十六位小数。你的号码比JavaScript可以处理的数字更多，所以你最终得到一个近似值。

JavaScript represents numbers using IEEE-754 double-precision (64 bit) format. As I understand it this gives you 53 bits precision, or fifteen to sixteen decimal digits. Your number has more digits than JavaScript can cope with, so you end up with an approximation.

这不是真的错误处理，但显然它不是'如果您需要大数字的完全精确度，这将非常有用。有一些JS库可以处理更大的数字，例如 BigNumber 和 Int64 。

This isn't really "mishandling" as such, but obviously it isn't very helpful if you need full precision on large numbers. There are a few JS libraries around that can handle larger numbers, e.g., BigNumber and Int64.

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