べき乗代入 (**=)
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.
べき乗代入演算子 (**=) は、変数の値を右オペランドでべき乗します。
試してみましょう
let a = 3; console.log((a **= 2)); // Expected output: 9 console.log((a **= 0)); // Expected output: 1 console.log((a **= "hello")); // Expected output: NaN 構文
js
x **= y; // x = x ** y 例
べき乗代入の仕様
js
// 次の変数を想定 // bar = 5 bar **= 2; // 25 bar **= "foo"; // NaN 仕様書
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-assignment-operators |
