please help im lost

Write a recursive function, `sum(arr, n)`

, that returns the sum of the first `n`

elements of an array `arr`

.

```
function sum(arr, n) {
// Only change code below this line
if (n <= 0) {
return 1;
} else {
return sum(arr, n - 1) + arr[n - 1]
}
// Only change code above this line
}
```