Bitwise AND assignment (&=)
BaselineWidely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
Thebitwise AND assignment (&=) operator performsbitwise AND on the two operands and assigns the result to the left operand.
Try it
let a = 5; // 00000000000000000000000000000101a &= 3; // 00000000000000000000000000000011console.log(a); // 00000000000000000000000000000001// Expected output: 1Syntax
js
x &= yDescription
x &= y is equivalent tox = x & y, except that the expressionx is only evaluated once.
Examples
Using bitwise AND assignment
js
let a = 5;// 5: 00000000000000000000000000000101// 2: 00000000000000000000000000000010a &= 2; // 0let b = 5n;b &= 2n; // 0nSpecifications
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-assignment-operators |