Odd even index difference - JavaScript

We are required to write a JavaScript function that takes in an array of numbers like this −

const arr = [3, 6, 34, 12, 6, 8, 8, 5, 6, 8];

The function should return the difference between the sum of elements present at the odd index and the sum of elements present at even index

Example

Following is the code −

const arr = [3, 6, 34, 12, 6, 8, 8, 5, 6, 8];
const oddEvenDiff = arr => {
   let diff = 0;
   for(let i = 0; i < arr.length; i++){
      if(i % 2 === 0){
         diff += arr[i];
      }else{
         diff -= arr[i]
      };
   };
   return Math.abs(diff);
};
console.log(oddEvenDiff(arr));

Output

This will produce the following output in console −

18