Javascript 模块化算法

Question

Javascript 将以下代码片段计算为 -1。

-5 % 4

我理解余数定理表明 a = bq + r 使得 0 ≤ r < b。鉴于上面的定义，答案不应该是 3 吗？为什么 JavaScript 返回 -1？

Answer 1

因为它是一个 remainder operator ，不是模数。但是有一个 proposal for a proper one .

引自 Ecma 5.1

remainder r from a dividend n and a divisor d is defined by the mathematical relation r = n − (d × q) where q is an integer that is negative only if n/d is negative and positive only if n/d is positive