Shell Sort in TypeScript

class ShellSort
{
   public sort(arr: number[])
   {
       let gap = 0;
       while(gap < Math.floor(arr.length / 3))
       {
           gap = gap * 3 + 1;
       }

       while(gap > 0)
       {
           for(let i = gap; i < arr.length; i++)
           {
               let j = i;
               const tmp = arr[i];

               while(j >= gap && arr[j - gap] > tmp)
               {
                   arr[j] = arr[j - gap];
                   j -= gap;
               }
               arr[j] = tmp;
           }
           gap = Math.floor((gap - 1) / 3);
       }
   }
}