Quicksort in TypeScript

class Quicksort
{
   public sort(arr: number[])
   {
       this.quicksort(arr, 0, arr.length - 1);
   }

   private quicksort(arr: number[], low: number, high: number)
   {
       if(low < high)
       {
           const p = this.partition(arr, low, high);

           this.quicksort(arr, low, p - 1);
           this.quicksort(arr, p + 1, high);
       }
   }

   private partition(arr: number[], low: number, high: number) : number
   {
       const pivot = arr[high];
       let i = low;
       for(let j = low; j < high; j++)
       {
           if(arr[j] < pivot)
           {
               this.swap(arr, i, j);
               i++;
           }
       }
       this.swap(arr, i, high);
       return i;
   }

   private swap(arr: number[], a: number, b: number)
   {
       const tmp = arr[a];
       arr[a] = arr[b];
       arr[b] = tmp;
   }
}