Bitwise Operators in JavaScript

Bitwise operators treat their operands as a set of 32 bits (binary digits), rather than as decimal, hexadecimal, or octal numbers. They operate on the binary representations of the numbers.

Here are the basic bitwise operators:

1. Bitwise AND (&)

  • Compares each bit of the first operand to the corresponding bit of the second operand.
  • If both bits are 1, the corresponding result bit is set to 1. Otherwise, the corresponding result bit is set to 0.

Example:

5 & 1

Binary representation:

5 = 0101
1 = 0001
---------
Result: 0001 (which is 1 in decimal)

Explanation: Only the last bit is 1 in both numbers, so the result is 1.

2. Bitwise OR (|)

  • Compares each bit of the first operand to the corresponding bit of the second operand.
  • If at least one of the bits is 1, the corresponding result bit is set to 1. Otherwise, it is set to 0.

Example:

5 | 1

Binary representation:

5 = 0101
1 = 0001
---------
Result: 0101 (which is 5 in decimal)

Explanation: At least one bit is 1 in the first, second, and fourth positions, so the result is 5.

3. Bitwise XOR (^)

  • Compares each bit of the first operand to the corresponding bit of the second operand.
  • If the bits are different, the corresponding result bit is set to 1. If they are the same, the result bit is set to 0.

Example:

5 ^ 1

Binary representation:

5 = 0101
1 = 0001
---------
Result: 0100 (which is 4 in decimal)

Explanation: Only the second bit is different, so the result is 4.

4. Bitwise NOT (~)

  • Inverts all the bits of the operand.
  • Changes 0s to 1s and 1s to 0s.

Example:

~5

Binary representation:

5 = 0000 0101
~5 = 1111 1010 (which is -6 in decimal, using two's complement representation)

Explanation: All bits are inverted.

5. Bitwise Left Shift (<<)

  • Shifts the bits of the first operand to the left by the number of positions specified by the second operand.
  • New bits are filled with 0s.

Example:

5 << 1

Binary representation:

5 = 0101
5 << 1 = 1010 (which is 10 in decimal)

Explanation: All bits are shifted one position to the left, and a 0 is added at the end.

6. Bitwise Right Shift (>>)

  • Shifts the bits of the first operand to the right by the number of positions specified by the second operand.
  • For non-negative numbers, new bits are filled with 0s.

Example:

5 >> 1

Binary representation:

5 = 0101
5 >> 1 = 0010 (which is 2 in decimal)

Explanation: All bits are shifted one position to the right, and a 0 is added at the beginning.

7. Bitwise Zero Fill Right Shift (>>>)

  • Shifts the bits of the first operand to the right by the number of positions specified by the second operand.
  • New bits are filled with 0s.

Example:

5 >>> 1

Binary representation:

5 = 0101
5 >>> 1 = 0010 (which is 2 in decimal)

Explanation: All bits are shifted one position to the right, and a 0 is added at the beginning.

Summary

Bitwise operators perform operations on the binary representations of numbers:

  • AND (&): Returns 1 if both bits are 1.
  • OR (|): Returns 1 if at least one bit is 1.
  • XOR (^): Returns 1 if bits are different.
  • NOT (~): Inverts the bits.
  • Left Shift (<<): Shifts bits to the left, filling with 0s.
  • Right Shift (>>): Shifts bits to the right, filling with 0s for non-negative numbers.
  • Zero Fill Right Shift (>>>): Shifts bits to the right, filling with 0s.

These operators are useful for low-level programming tasks, such as manipulating individual bits within a byte.