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 2015年7月.
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 |