Bitwise OR 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 OR assignment (|=) operator performs bitwise OR on the two operands and assigns the result to the left operand.

Try it

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

console.log(a); // 00000000000000000000000000000111
// Expected output: 7

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 OR assignment

js
let a = 5;
a |= 2; // 7
// 5: 00000000000000000000000000000101
// 2: 00000000000000000000000000000010
// -----------------------------------
// 7: 00000000000000000000000000000111

let b = 5n;
b |= 2n; // 7n

Specifications

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

Browser compatibility

BCD tables only load in the browser

See also