Merge Sort in TypeScript

class MergeSort
{
   arrClone : number[];

   public sort(arr: number[])
   {
       // Clone the array for sorting.
       this.arrClone = Object.assign([], arr);
       this.sortAux(arr, 0, arr.length - 1);

   }

   private sortAux(arr: number[], low: number, high: number)
   {
       if(low < high)
       {
           const mid = Math.floor((low + high) / 2);

           this.sortAux(arr, low, mid);
           this.sortAux(arr, mid + 1, high);

           this.merge(arr, low, mid, high);

       }
   }

   private merge(arr: number[], low: number, mid: number, high: number)
   {
       let i = low;
       let j = mid + 1;
       let k = 0;

       for(k = low; k <= high; k++)
       {
           this.arrClone[k] = arr[k];
       }

       for(k = low; k <= high; k++)
       {
           if( i > mid)
           {
               arr[k] = this.arrClone[j];
               j++;
           }
           else if(j > high)
           {
               arr[k] = this.arrClone[i];
               i++;
           }
           else if(this.arrClone[i] > this.arrClone[j])
           {
               arr[k] = this.arrClone[j];
               j++;
           }
           else
           {
               arr[k] = this.arrClone[i];
               i++;
           }
       }
   }
}