Left shift 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 left shift assignment (<<=) operator performs left shift on the two operands and assigns the result to the left operand.

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Syntax

js
x <<= y

Description

x <<= y is equivalent to x = x << y, except that the expression x is only evaluated once.

Examples

Using left shift assignment

js
let a = 5;
// 00000000000000000000000000000101

a <<= 2; // 20
// 00000000000000000000000000010100

let b = 5n;
b <<= 2n; // 20n

Specifications

Specification
ECMAScript Language Specification
# sec-assignment-operators

Browser compatibility

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See also