Proper way to convert number to string in javascript

Question

According to tutorial by w3schools (http://www.w3schools.com/jsref/tryit.asp?filename=tryjsref_tostring_number), we can use toString() method on a integer var. Kindly look at the following code:

var num = 15;
var n = num.toString();
alert(isNaN(n));

If toString() method is working, why isNaN(n) returning false?

Jongware · Accepted Answer · 2015-06-11 08:43:15Z

3

The IsNaN method tries converting the string passed to it back to a number, and since "15" is still actually a number, the method returns false.

Jongware

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answered Jun 11, 2015 at 8:42

Alen Genzić

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Comments

Oka · Accepted Answer · 2015-06-11 08:49:46Z

1

isNaN() coerces the string '15' into a number value before checking it.

isNaN even coerces booleans, and some falsy values into numbers.

isNaN(true) // >> false
isNaN(false) // >> false
isNaN([]) // >> false
isNaN('') // >> false

Try using typeof to figure out if it's a number or not

var num = 15;
var n = num.toString();
alert(typeof n === 'number');

answered Jun 11, 2015 at 8:43

Oka

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Mukesh Kalgude · Accepted Answer · 2015-06-11 08:43:51Z

-1

isNaN() function returns true if the value is NaN, and false if not. Your code is excute alert(isNaN(15));

So it is return false

answered Jun 11, 2015 at 8:43

Mukesh Kalgude

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