Extend the number class

Question

I want to extend the number class to have instance functions such as odd and even so I can do something like this:

2.odd() => false
         


        

Answer 1

You can extend natives JS objects by using (for example) Number.prototype.myFn = function(){}.

So you could do :

Math.prototype.odd = function(n){
    return n % 2 === 0;
};

Math.prototype.even = function(n){
    return n % 2 === 1;
};

And then use it like so :

var two = 2;
console.log(Math.odd(2)); // true

BUT I would strongly advise you against extending natives in JavaScript. You can read more about it here

EDIT : After trying my code on JSFiddle, it appears the Math object has no prototype, you can read more about it here. The code above won't work !

Instead, you could do :

Math.odd = function(n){
    return n % 2 === 0;
};

Math.even = function(n){
    return n % 2 === 1;
};

console.log(Math.odd(2)); // true

or :

Number.prototype.odd = function(){
    return this % 2 === 0;
};

Number.prototype.even = function(){
    return this % 2 === 1;
};

console.log(new Number(2).odd()); // true