I wrote a more detailed article on bitwise operators published on the LogRocket blog. Check it out here: Interesting use cases for JavaScript bitwise operators.

Although bitwise operators are sparingly used in JavaScript programs, they have quite a number of interesting applications. This post shows 5 simple applications of bitwise operators.

## 1. Even or Odd

No doubt the most popular way of checking if an integer is even or odd is by using the remainder operator (`%`

) like so:

For signed integers that can be fully represented in 32 bits, the bitwise AND (`&`

) operator can be used to check if the least significant bit is set. If it is set (that is set to **1**), the integer is odd, otherwise it is even. Hence the previous functions become:

## 2. Includes

In ES6, the `includes()`

method was added to the prototypes for the `Array`

and `String`

constructors to check if they contain a particular element or substring and return a boolean indicating the presence.

Prior to ES6, one of the available methods is the `indexOf()`

method which returns the index of the element or substring if present and `-1`

otherwise. Since JavaScript bitwise operators represent integers in *two's complement format*, `-1`

is the integer with all bits set to **1**, and its complement is `0`

(with all bits set to **0**).

This information can be used to create a simple `includes()`

function that is based on `indexOf()`

like so:

## 3. Powers of 2

Bitwise shift operators can be used to perform some quick arithmetic with powers of 2. The left shift (`<<`

) operator can be used to quickly multiply integers by powers of 2. Given that (** 0 <= a < 32**):

The sign-propagating right shift (`>>`

) operator can be used to quickly perform integer division by powers of 2. Given that (** 0 <= a < 32**):

The above can be used in algorithms like **binary search**, where you need to find the midpoint of an array like so:

## 4. Truncating Floats

Bitwise operators convert their operands to 32-bit integers. This has a truncating effect on operands that are floats.

The bitwise NOT (`~`

) operator can be used to truncate a float to an integer (remove the decimal portion of a float).

Given that (** -2147483649 < a < 2147483648**):

The bitwise OR (`|`

) operator can also be used in like manner to truncate a float to an integer like so:

## 5. Color Conversions

Bitwise operators can be used to convert color representations from RGB to hexadecimal and vice-versa. Each RGB color component (red, green and blue) ranges from 0 - 255, and can be fully represented with 8 bits.

Hence RGB color can be fully represented by a 24-bit integer, where the first (most significant) 8 bits represent the red, the next 8 bits represent the green and the last (least significant) 8 bits represent the blue.

Based on this information, we can convert a color representation from RGB to hexadecimal using the bitwise left shift (`<<`

) and OR (`|`

) operators as follows:

**Note:** *The above function isn't reliable for RGB color component values lower than 16. For example: rgbToHex([0, 128, 255]) will return #80ff.*

To convert from hexadecimal to RGB representation, we need to work in the reverse direction to extract each color component using the bitwise right shift (`>>`

) and AND (`&`

) operators like so:

**Note:** *The above function will not work for hexadecimal colors in compact form (3 hexadecimal digits). For example: hexToRgb('#3ff') will return [0, 0, 0].*

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