Javascript algorithm problem

Question

https://code.sololearn.com/WrCqVk6emfXQ/?ref=app
Why arr variable not store the add up values?

Answer 1

Saad Mughal ahh, ok. Only replace in line 4:

let arr;

Instead

let arr=0;

Cause' when you declarate let arr; arr has "undefined" value, so if you try arr+=2; (undefined+2) you get NaN

Answer 2

Try this:

function oddOrEven(array) {
return array.map( num => num % 2 === 0?"even":"odd");

}
console.log(oddOrEven([0,5,9]));

//Output will be
//even,odd, odd

Answer 3

luis calderón Thanks it's working now

Answer 4

I want To sum all the Elements in array and find there sum is even or odd
And I just want To know in my logic what is the problem

Answer 5

Intialize arr with 0;
When you do
arr+=array[i]
You are basically adding arr=arr+array[i]
While arr has no value and it is returning NaN

um I didn't noticed that Luis already gave an answer ,really slow net