Left Shift Assignment (<<=) Operator in JavaScript (original) (raw)

Last Updated : 23 Jul, 2025

The Left Shift Assignment Operator is represented by "<<=". This operator moves the specified number of bits to the left and assigns that result to the variable. We can fill the vacated place by 0. The left shift operator treats the integer stored in the variable to the operator's left as a 32-bit binary number. This can also be explained as the number is shifted to the left by the integer which is the right of the operator and assign the result to the variable.

Syntax

a <<= b Or a = a << b

Where -

Example 1: In this example, we will see the implementation of the left shift assignment.

JavaScript `

let x = 7; // 00000000000000000000000000000111

x <<= 2; // 00000000000000000000000000011100

console.log(x);

`

Example 2: In this example, we will see left shift operator is not used for the negative number.

JavaScript `

let x = 1; // 00000000000000000000000000000001 x <<= -1; // -10000000000000000000000000000000

console.log(x);

`

Example 3: In this example, we will see the implementation of the left shift assignment operator.

JavaScript `

let a = 10; // 00000000000000000000000000001010 let b = 5 // 00000000000000000000000000000101 a = a << b; // 00000000000000000000000101000000

console.log(a);

`

We have a complete list of Javascript Assignment Operators, Please check this article Javascript Assignment Operator.

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