JavaScript Bitwise Operators

JavaScript Bitwise Operators

Bitwise operators treat its operands as a set of 32-bit binary digits (zeros and ones) and perform actions. However, the result is shown as a decimal value.

Note: The minimum and the maximum integers that are representable through a 32-bit signed number are -2147483648 to 2147483647.

JavaScript Bitwise AND

Bitwise AND & returns 1 if the corresponding bits of both operands are 1 else it returns 0.

Let's take a look at the bitwise AND operation of two integers 12 and 25.

In binary,

12 = 01100
25 = 11001

// Bitwise AND Operation of 12 and 25

    00001100
&   00011001
    ---------
    00001000  = 8 (In decimal)

Note: Converting 12 to 32-bit binary gives us 00000000000000000000000000001100 and 25 gives 00000000000000000000000000011001. However, we have removed the preceding zeros for simplicity.

Example 1: Bitwise AND Operator

// bitwise AND operator example

let a = 12; 
let  b = 25; 

result = a & b; 
console.log(result); // 8 

In the above program,

• The binary value of 12 is 00000000000000000000000000001100
• The binary value of 25 is 00000000000000000000000000011001.
• When bitwise AND operation is performed, the binary result will be 00000000000000000000000000001000 which converts into the decimal value 8.

JavaScript Bitwise OR

Bitwise OR | returns 1 if either of the corresponding bits of one operand is 1 else returns 0.

Let's take a look at the bitwise OR operation of two integers 12 and 25.

In binary,

12 = 01100
25 = 11001

// Bitwise OR Operation of 12 and 25

    00001100
|   00011001
    --------
    00011101  = 29 (In decimal)

Example 2: Bitwise OR Operator

// bitwise OR operator example
let a = 12; 
let  b = 25; 

result = a | b; 
console.log(result); // 29

When bitwise OR operation is performed, the binary result will be 00000000000000000000000000011101 which converts into the decimal value 29.

JavaScript Bitwise XOR

Bitwise XOR ^ returns 1 if the corresponding bits are different and returns 0 if the corresponding bits are the same.

In binary,

12 = 01100
25 = 11001

// Bitwise XOR Operation of 12 and 25

    00001100
^   00011001
    --------
    00010101  = 21 (In decimal)

Example 3: Bitwise XOR Operator

// bitwise XOR operator example
let a = 12; 
let  b = 25; 

result = a ^ b; 
console.log(result); // 21

When bitwise XOR operation is performed, the binary result will be 00000000000000000000000000010101 which converts into the decimal value 21.

JavaScript Bitwise NOT

Bitwise NOT ~ inverts the bit( 0 becomes 1, 1 becomes 0).

In binary,

12 = 00000000000000000000000000001100

// Bitwise Not Operation of 12 

    ~ 00000000000000000000000000001100
      ---------------------------------
      11111111111111111111111111110011  = -13(In decimal)

While converting 11111111111111111111111111110011 to decimal, the value would be 4294967283. But when using bitwise operator, the value is computed in signed 2's complement format except for zero-fill right shift.

2's complement is computed by inverting the bits(1's complement) and then adding 1. For example,

13 in binary: 00000000000000000000000000001101
1's complement of 13: 11111111111111111111111111110010

2's complement of 13: 11111111111111111111111111110010
                                                    +1
                      ---------------------------------
                      11111111111111111111111111110011

Notice the 2's complement of 13 (i.e. -13) is 11111111111111111111111111110011. This value is equivalent to the bitwise NOT of 12.

Example 4: Bitwise NOT Operator

// bitwise NOT operator example
let  b = 12;

result = ~b;

console.log(result); // -13

When bitwise NOT operation is performed, the binary result will be 11111111111111111111111111110011 which converts into the decimal value -13.

Note: Bitwise NOT of a number x gives -(x + 1). Notice above ~2 gives -3.

JavaScript Left shift

In the left shift operator <<, the left operand specifies the number and the right operand specifies the number to be shifted left. Zero bits are added to the right and excess bits from the left are discarded.

For example,

let a = 8;
let  b = 1;

result = a << b;

// 1 ( 00000000000000000000000000010000 )
console.log(result);

JavaScript Sign-propagating right shift

In the right shift operator >>, the first operand specifies the number and the second operand specifies the number to be shifted right. Excess bits from the right are discarded. The copies of the leftmost bit are shifted in from the left, hence the name sign-propagating.

For example,

let a = 8;
let b = 1;
// 11111111111111111111111111111101
let c = -3;

result = a >> b;
result1 = c >> b;

// 4 (00000000000000000000000000000100)
console.log(result); 

// -2 (11111111111111111111111111111110)
console.log(result1); 

JavaScript Zero-fill right shift

Zero-fill right shift >>> shifts the operand to the right by filling the zero bits to the left. Excess bits from the right are discarded.

For example,

let a = 8;
let b = 1;
let c = -3; 

result = a >>> b;
result1 = c >>> b;

// 4 (00000000000000000000000000000100)
console.log(result);

// 1073741823 (00111111111111111111111111111111)
console.log(result);