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.
Try it
let a = 5; // 00000000000000000000000000000101 a <<= 2; // 00000000000000000000000000010100 console.log(a); // Expected output: 20
Syntax
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
let a = 5; // 00000000000000000000000000000101 a <<= 2; // 20 // 00000000000000000000000000010100 let b = 5n; b <<= 2n; // 20n
Specifications
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 | |
left_shift_assignment |
1 |
12 |
1 |
3 |
1 |
18 |
4 |
10.1 |
1 |
1.0 |
4.4 |
1 |
1.0.0 |
1.0 |
0.10.0 |
See also
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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
