JavaScript - bitwise XOR operator
The main goal of this article is to show how bitwise XOR operation (^ operator, called: Exclusive OR) works on the JavaScript example.
The main concept of the bitwise XOR operation is to make XOR operations on each corresponding bits.
Quick solution:
xxxxxxxxxxconst a = 3; // 0011const b = 5; // 0101const result = a ^ b; // <----- bitwise XOR operation exampleconsole.log(result); // 6 (in dec / base 10)console.log(result.toString(2).padStart(4, '0')); // 0110 (in bin / base 2 )
The truth table for the XOR operation is:
| a | b | a XOR b (in JavaScript: a ^ b) | JS Example |
| 0 | 0 | 0 | 0 ^ 0 === 0 |
| 0 | 1 | 1 | 0 ^ 1 === 1 |
| 1 | 0 | 1 | 1 ^ 0 === 1 |
| 1 | 1 | 0 | 1 ^ 1 === 0 |
So, the above table can be presented in JavaScript as:
xxxxxxxxxxconsole.log(0 ^ 0); // 0console.log(0 ^ 1); // 1console.log(1 ^ 0); // 1console.log(1 ^ 1); // 0
xxxxxxxxxxconst a = 3; // 00000011const b = 5; // 00000101const result = a ^ b; // <----- bitwise XOR operation example // (in dec / base 10)console.log(a); // 3 console.log(b); // 5console.log(result); // 6 // (in bin / base 2 )console.log(getBits(a, 8)); // 00000011console.log(getBits(b, 8)); // 00000101console.log(getBits(result, 8)); // 00000110// Helpers:function getBits(number, length) { let text = ''; for (let i = length - 1; i > -1; --i) { text += 0x01 & (number >> i); } return text;}
Hint: in JavaScript, bitwise XOR works on 32-bit integers. If number is bigger, the most significant bits are dicarded to get 32-bit integer number - it means only bits indexed from 0 to 31 will be used.
So, the above table can be also written as:
xxxxxxxxxx 3 (base 10) = 00000000000000000000000000000011 (base 2) 5 (base 10) = 00000000000000000000000000000101 (base 2) --------------------------------3 ^ 5 (base 10) = 00000000000000000000000000000110 (base 2) = 6 (base 10)
1. bitwise XOR operation is fast - easy to do by any CPU.
2. bitwise XOR operation can be inverted - it means, we do not lose any information with that operation, e.g.
xxxxxxxxxxconst a = 3; // 0011const b = 5; // 0101const result = a ^ b;const a2 = result ^ b; // <-------- bitwise XOR inversion: a achieved with bconst b2 = result ^ a; // <-------- bitwise XOR inversion: b achieved with aconsole.log(a2); // 3 (0011)console.log(b2); // 5 (0011)
