剰余代入 (%=)

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

剰余代入演算子 (%=) は、変数を右辺のオペランドの値で除算し、剰余を変数に代入します。

試してみましょう

let a = 3;

console.log((a %= 2));
// Expected output: 1

console.log((a %= 0));
// Expected output: NaN

console.log((a %= "hello"));
// Expected output: NaN

構文

js
x %= y; // x = x % y

剰余代入の使用

js
// 以下の変数を想定
//  bar = 5

bar %= 2; // 1
bar %= "foo"; // NaN
bar %= 0; // NaN

仕様書

Specification
ECMAScript® 2025 Language Specification
# sec-assignment-operators

ブラウザーの互換性

Report problems with this compatibility data on GitHub
desktopmobileserver
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Deno
Node.js
Remainder assignment (x %= y)

Legend

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Full support
Full support

関連情報