Bitwise AND assignment (&=) - JavaScript | MDN

Try it

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

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

Syntax

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® 2027 Language Specification
# sec-assignment-operators

Browser compatibility

See also

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