Heap Sort in TypeScript

class HeapSort
{
   public sort(arr: number[])
   {
       const size = arr.length;

       for(let i = Math.floor(size / 2) - 1; i >= 0; i--)
       {
           this.heapify(arr, size, i);
       }

       let j = size - 1;
       while(j >= 1)
       {
           this.swap(arr, 0, j);
           this.heapify(arr, j, 0);
           j--;
       }
   }

   private heapify(arr: number[], size: number, i: number)
   {
       let largest = i;

       let leftLeaf = 2 * i + 1;
       let rightLeaf = 2 * i + 2;

       // If the left child is larger than the current largest.
    if (leftLeaf < size && arr[leftLeaf] > arr[largest]) 
       {
        largest = leftLeaf;
    }
    // If the right child is larger than the current largest.
    if (rightLeaf < size && arr[rightLeaf] > arr[largest]) 
       {
        largest = rightLeaf;
    }
    
    // If the largest of the two is not the original largest
    if (largest != i) 
       {
        // Swap i and the largest.
        this.swap(arr, i, largest);
        // Heapify the sub-tree. 
        this.heapify(arr, size, largest); 
    }
   }

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