Merge Sort Using JavaScript

mergeSort.js

var unsortedArr = [10, 55, 20, 4, 28, 69, 22, 85, 7, 37];

function merge( arr, left, mid, right)
{
    const n1 = mid - left + 1
    const n2 = right - mid;
    const LA = new Array(n1);
    const RA = new Array(n2);

    for(let i = 0; i< n1; i++)
        LA[i] = arr[left + i];
    for(let j = 0; j < n2; j++)
        RA[j] = arr[mid +j + 1];

   let i = j = 0
   let k = left;
   while(i < n1 && j < n2) {
        if (LA[i] < RA[j]){
            arr[k] = LA[i];
            i++;
        } else {
            arr[k] = RA[j];
            j++;
        }
        k++;
   }

   while (i<n1) {
        arr[k] = LA[i];
        i++;
        k++;
   }

   while (j<n2) {
    arr[k] = RA[j];
    j++;
    k++;
   }

}

function mergeSort(arr, left, right)
{
    if (left >= right)
        return;


    const mid = Math.floor(left + (right - left) / 2);

    mergeSort(arr, left, mid);
    mergeSort(arr, mid + 1, right);
    merge(arr, left, mid, right);

    return arr;
}

console.log(mergeSort(unsortedArr, 0, unsortedArr.length - 1));

Merge Sort
Description: Divides the array into halves, recursively sorts them, and then merges the sorted halves.
Time Complexity: O(n log n)
Use Case: Efficient for large datasets, uses additional space for merging.