幂赋值（**=）
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since March 2017.
幂赋值（**=）对两个操作数执行幂运算，并将结果赋给左操作数。
尝试一下
let a = 3; console.log((a **= 2)); // Expected output: 9 console.log((a **= 0)); // Expected output: 1 console.log((a **= 'hello')); // Expected output: NaN 语法
js
x **= y 描述
x **= y 和 x = x ** y 是等价的，不同之处在于前者的 x 只被计算一次。
示例
使用数字进行幂赋值
js
let bar = 5; bar **= 2; // 25 其他非 BigInt 值会被强制转换为数字：
js
let baz = 5; baz **= "foo"; // NaN 使用 BigInt 进行幂赋值
js
let foo = 3n; foo **= 2n; // 9n foo **= 1; // TypeError: Cannot mix BigInt and other types, use explicit conversions 规范
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-assignment-operators |
