Heap Sort

function heapify(n, i) {
  let largest = i;
  const left = 2 * i + 1;
  const right = 2 * i + 2;
  if (left < n && compare(left, largest))
    largest = left;
  if (right < n && compare(right, largest))
    largest = right;
  if (largest !== i) {
    swap(i, largest);
    heapify(n, largest);
  }
}
// Build max heap
for (let i = (length >> 1) - 1; i >= 0; i--) {
  heapify(length, i);
}
// Extract elements
for (let i = length - 1; i > 0; i--) {
  swap(0, i);
  heapify(i, 0);
}