乗算代入 (*=)
BaselineWidely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
乗算代入演算子 (*=) は、変数に右のオペランドの値を乗算し、結果を変数に代入します。
試してみましょう
let a = 2;console.log((a *= 3));// Expected output: 6console.log((a *= "hello"));// Expected output: NaN構文
js
x *= y; // x = x * y例
乗算代入の使用
js
// 次の変数を想定// bar = 5bar *= 2; // 10bar *= "foo"; // NaN仕様書
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-assignment-operators |