I tried the following to check for the datatype (specifically for integer), but not working.
var i = 5;
if(Number(i) = 'NaN')
{
console.log('This is not number'));
}
I think of two ways to test for the type of a value:
Method 1:
You can use the isNaN javascript method, which determines if a value is NaN or not. But because in your case you are testing a numerical value converted to string, Javascript is trying to guess the type of the value and converts it to the number 5 which is not NaN. That's why if you console.log out the result, you will be surprised that the code:
if (isNaN(i)) {
console.log('This is not number');
}
will not return anything. For this reason a better alternative would be the method 2.
Method 2:
You may use javascript typeof method to test the type of a variable or value
if (typeof i != number) {
console.log('This is not number');
}
Notice that i'm using double equal operator, because in this case the type of the value is a string but Javascript internally will convert to Number.
A more robust method to force the value to numerical type is to use Number.isNaN which is part of new Ecmascript 6 (Harmony) proposal, hence not widespread and fully supported by different vendors.
