How to check if a JavaScript number is a real, valid number?

Question

MY code is:

function isNumber(n){
return typeof n == \'number\' && !isNaN(n);
}

window.onload=function(){
var a=0,b=1,c=2.2,d=-3,e=-4.4,f=10/3;
var          


        

Answer 1

If you consider a number in its object wrapper to be a number, then it will fail with:

isNumber( new Number(123) )

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Since a downvoter is having some comprehension troubles that couldn't be alleviated by a simple test, new Number(123) will return 'object' from the typeof test, and as such will not pass.