按位非 (~)

¥Syntax

~x

¥Description

~ 运算符针对两种类型的操作数进行重载：编号和 BigInt。对于数字，该运算符返回一个 32 位整数。对于 BigInts，该运算符返回一个 BigInt。它首先 将操作数强制为数值 并测试它的类型。如果操作数变为 BigInt，则执行 BigInt NOT；否则，它将操作数转换为 32 位整数 并执行数字按位 NOT。

¥The ~ operator is overloaded for two types of operands: number and BigInt. For numbers, the operator returns a 32-bit integer. For BigInts, the operator returns a BigInt. It first coerces the operand to a numeric value and tests the type of it. It performs BigInt NOT if the operand becomes a BigInt; otherwise, it converts the operand to a 32-bit integer and performs number bitwise NOT.

该运算符对 二进制补码 中操作数的位表示进行运算。该运算符应用于每一位，并按位构造结果。

¥The operator operates on the operands' bit representations in two's complement. The operator is applied to each bit, and the result is constructed bitwise.

NOT 运算的真值表为：

¥The truth table for the NOT operation is:

 9 (base 10) = 00000000000000000000000000001001 (base 2)
               --------------------------------
~9 (base 10) = 11111111111111111111111111110110 (base 2) = -10 (base 10)

超过 32 位的数字将丢弃其最高有效位。例如，以下超过 32 位的整数将被转换为 32 位整数：

¥Numbers with more than 32 bits get their most significant bits discarded. For example, the following integer with more than 32 bits will be converted to a 32-bit integer:

Before: 11100110111110100000000000000110000000000001
After:              10100000000000000110000000000001

对于 BigInts，没有截断。从概念上讲，将正 BigInt 理解为具有无限数量的前导 0 位，将负 BigInt 理解为具有无限数量的前导 1 位。

¥For BigInts, there's no truncation. Conceptually, understand positive BigInts as having an infinite number of leading 0 bits, and negative BigInts having an infinite number of leading 1 bits.

按位对任何 32 位整数 x 进行 NOT 运算会得到 -(x + 1)。例如，~-5 产生 4。

¥Bitwise NOTing any 32-bit integer x yields -(x + 1). For example, ~-5 yields 4.

对任意数字 x 进行按位取反两次会返回转换为 32 位整数的 x。不要使用 ~~x 将数字截断为整数；使用 Math.trunc() 代替。由于数字使用 32 位表示，~-1 和 ~4294967295 (2³² - 1) 都会生成 0。

¥Bitwise NOTing any number x twice returns x converted to a 32-bit integer. Do not use ~~x to truncate numbers to integers; use Math.trunc() instead. Due to using 32-bit representation for numbers, both ~-1 and ~4294967295 (2³² - 1) result in 0.

¥Examples

¥Using bitwise NOT

~0; // -1
~-1; // 0
~1; // -2

~0n; // -1n
~4294967295n; // -4294967296n

¥See also

• JS 指南中的位运算符