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

, that returns the sum of the first `n`

elements of an array `arr`

.

this code work correctly but i’m not understand please give me explanation?

function sum(arr, n) {

// Only change code below this line

if(n <= 0){

return 0;

}

else{

return sum(arr,n-1) + arr[n-1];

}

// Only change code above this line

}

console.log(sum([1],0))