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® 2025 Language Specification # sec-assignment-operators |
浏览器兼容性
Report problems with this compatibility data on GitHubdesktop | mobile | server | ||||||||||||
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Exponentiation assignment ( x **= y ) |
Legend
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- Full support
- Full support
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