Javascript Challenge Query

Question

Can somebody explain to me, what is going on here ?
var x = 50, y = 5, z = x % y;
var zero = new Number(z);
document.write(zero == true); // gives false
if (zero) { // but here it executes...
document.write(true);
}

Answer 1

Hi Sp Maurya
I try to explain it in 4 steps😊

var x = 50, y = 5, z = x % y;
var zero = new Number(z);

//1 .here new number creates an object with value
//of z . Result=> {0}

document.write(zero == true); // false

// 2. Its false because the object {0} itself
// is not equal to true

// 3. Your can check the value of an object with
//valueOf() method .
//result=> {0}.valueOf() is equal with 0

if (zero) {
document.write(true);
}
//4. Remember always an object with any value
//even falsy values are true when you consider it
//as a boolean. So that's why here the code inside
// block is running.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Boolean

Answer 2

Sp Maurya

here zero is an object

Check console.log(typeof zero)

if (object) will always return true but object == true will return false

Answer 3

50 % 5 = 0

So now check what is the value of zero

new Number(z) will return object so
object == true // false

if(object) //true

Answer 4

Sp Maurya

if you just write zero = Number(z)
then second will not execute.

Answer 5

A͢J
Oh i see... Thanks...

Answer 6

Yasin Rahnaward thanks brother for the effort... You made it a lot clearer...

Answer 7

Yes they are NAN,false,undefined,0,empty string

Answer 8

En résumé, le code teste la conversion de l'objet Number en une valeur booléenne, qui renvoie false car un objet est considéré comme faux lorsqu'il est comparé à une valeur booléenne. Cependant, l'objet est toujours considéré comme "truthy" lorsqu'il est utilisé dans une expression booléenne, ce qui permet à if (zero) de s'exécuter.

Answer 9

A͢J
Yep that much i know...
Like
if (0) {
// not executes
}
if (zero) {
// but this executes
}

Answer 10

And if i'm right falsy means the value which when converted to boolean results in false...

Answer 11

Javascript Challenge Query

Can somebody explain to me, what is going on here ?
var x = 50, y = 5, z = x % y;
var zero = new Number(z);
document.write(zero == true); // gives false
if (zero) { // but here it executes...
document.write(true);
}