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Bitwise OR assignment (|=)

View on MDN ↗

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

Interactive exampleOpen the canonical MDN source to run this embedded demo.
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

SpecificationsStandards references are available on the canonical MDN page.

Browser compatibility

Browser compatibilityCompatibility data is available on the canonical MDN page.

See also