Why can I use (myVar & 1) to test partity and should I do it in Javascript?

Question

I'm working with JS, I was trying to implement an algorithm while I realize that I could use myVar & 1 to return 0 or 1 according to the parity of the number in myVar.

var a = 0 & 1;
var b = 1 & 1;
var c = 42 & 1;
var d = 65 & 1;

console.log(a); //display 0
console.log(b); //display 1
console.log(c); //display 0
console.log(d); //display 1

https://jsfiddle.net/bzjvpyjk/

I don't understand what's happening behind it. How does it work?

Is it clear or even useful to do it?

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Bitwise_Operators — brso05, Jan 18 '16 at 14:56

score 1 · Answer 1 · answered Jan 18 '16 at 15:01

// 9 is 00000000000000000000000000001001
var expr1 = 9;

// 5 is 00000000000000000000000000000101
var expr2 = 5;

// 1 is 00000000000000000000000000000001
var result = expr1 & expr2;// performing and(&) operation

 document.write(result);
// Output: 1

For more info https://msdn.microsoft.com/en-us/library/dazfy1f3(v=vs.94).aspx

Why can I use (myVar & 1) to test partity and should I do it in Javascript?

1 Answers1