Javascript数字中的位数 [英] Number of bits in Javascript numbers

问题描述

我只在Javascript中使用整数（主要是添加数字并移动它们）。我不知道他们有多大可以不丢失任何一点。

I work in Javascript with integer numbers only (mainly adding numbers and shifting them). I wonder how big they can be without loosing any bits.

例如， X 的大小可以是 1<< X 将代表 2 ^ X ？

For example, how big X can be such that 1 << X will represent 2^X ?

推荐答案

JavaScript中的所有数字实际上都是符合IEEE-754标准的浮点数双精度数。它们具有53位尾数，这意味着任何大小约为9千万亿或更小的整数值 - 更具体地说，9,007,199,254,740,991 - 将被准确表示。

All numbers in JavaScript are actually IEEE-754 compliant floating-point doubles. These have a 53-bit mantissa which should mean that any integer value with a magnitude of approximately 9 quadrillion or less -- more specifically, 9,007,199,254,740,991 -- will be represented accurately.

注意：在2018年，主浏览器和NodeJS也在使用新的Javascript原始类型， BigInt ，用整数值幅度解决问题。

NOTICE: in 2018 main browsers and NodeJS are working also with the new Javascript's primitive-type, BigInt, solving the problems with integer value magnitude.

这篇关于Javascript数字中的位数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！