Left shift assignment (<<=) - JavaScript | MDN
Try it
let a = 5; // 00000000000000000000000000000101
a <<= 2; // 00000000000000000000000000010100
console.log(a);
// Expected output: 20
Syntax
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® 2026 Language Specification # sec-assignment-operators |