Finding sum of every nth element of array in JavaScript

We are required to write a JavaScript function that takes in an array of numbers and returns the cumulative sum of every number present at the index that is a multiple of n from the array.

Example

The code for this will be −

const arr = [5, 3, 5, 6, 12, 5, 65, 3, 2];
const num = 3;
const nthSum = (arr, num) => {
   let sum = 0;
   for(let i = 0; i < arr.length; i++){
      if(i % num !== 0){
         continue;
      };
      sum += arr[i];
   };
   return sum;
};
console.log(nthSum(arr, num));

Output

The output in the console −

76