Bitwise AND assignment (&=)

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.

The bitwise AND assignment (&=) operator performs bitwise AND on the two operands and assigns the result to the left operand.

Try it

let a = 5; // 00000000000000000000000000000101
a &= 3; // 00000000000000000000000000000011

console.log(a); // 00000000000000000000000000000001
// Expected output: 1

Syntax

js
x &= y

Description

x &= y is equivalent to x = x & y, except that the expression x is only evaluated once.

Examples

Using bitwise AND assignment

js
let a = 5;
// 5:     00000000000000000000000000000101
// 2:     00000000000000000000000000000010
a &= 2; // 0

let b = 5n;
b &= 2n; // 0n

Specifications

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

Browser compatibility

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
Bitwise AND assignment (x &= y)

Legend

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Full support
Full support

See also