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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 |= 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

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

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>

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_OR_assignment`	1	12	1	3	1	18	4	10.1	1	1.0	4.4	1	1.0.0	1.0	0.10.0