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® 2026 Language Specification # sec-assignment-operators |