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

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

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

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

Specifications

Specification
ECMAScript® 2027 Language Specification # sec-assignment-operators

Browser compatibility

	Desktop					Mobile							Server
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on iOS	Samsung Internet	WebView Android	WebView on iOS	Bun	Deno	Node.js
`bitwise_and_assignment`	1	12	1	3	1	18	4	10.1	1	1.0	4.4	1	1.0.0	1.0	0.10.0