W3cubDocs

/JavaScript

Left shift assignment (<<=)

The <<= operator performs left shift on the two operands and assigns the result to the left operand.

Try it

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

Desktop Mobile Server
Chrome Edge Firefox Opera Safari Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet WebView Android Deno Node.js
Left_shift_assignment 1 12 1 3 1 18 4 10.1 1 1.0 4.4 1.0 0.10.0

See also

© 2005–2023 MDN contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Left_shift_assignment