For this Question: Complete the function <code>countBy</code>
Such that it takes a initial number which is the defualt value of out counter. And returns 
a function which also takes a number and returns the initialCount + number supplied to second function.

Ex:-
<code>
const count = countBy(4) // initial value of counter 4, returns a function <br>
console. log(count(2)) // prints 6 because 4 + 2 <br>
console. log(count(-4)) // prints 2 because 6 - 4 <br>
console. log(count(8)) // prints 10 because 2 + 8 <br>
</code>

You have to return implement countBy function such that it can be run like that.<code>countBy</code> will take one number as input which will be the initial count.<code>countBy</code> will return a function which can be run many times and takes a number as input and returns the sum of it with previously maintained counter values<code>
const count = countBy(4) // initial value of counter 4, returns a function <br>
console. log(count(2)) // prints 6 because 4 + 2 <br>
console. log(count(-4)) // prints 2 because 6 - 4 <br>
console. log(count(8)) // prints 10 because 2 + 8 <br>
</code>, I have written this Solution Code: function countBy(initial){
    let copy = initial
    return (y)=>{
        copy += y
        return copy
    }
    // return the output using return keyword
    // do not console.log it

}, In this Programming Language: JavaScript, Now tell me if this Code is compilable or not?