一元减（-）
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
一元减（-）运算符在其操作数之前，并对其取反。
尝试一下
const x = 4;
const y = -x;
console.log(y);
// Expected output: -4
const a = "4";
const b = -a;
console.log(b);
// Expected output: -4
语法
js
-x
示例
数字取反
js
const x = 3;
const y = -x;
// y = -3
// x = 3
非数字取反
一元减运算符可以将非数字转换为数字。
js
const x = "4";
const y = -x;
// y = -4
规范
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-unary-minus-operator |