selection_sort.js

let arreglo = [9, 8, 4, 3, 2, 1, 3, 6, 8, 5, 4, 7, 6, 5, 4, 2, 3, 1]

function selection_sort(list)
{
  let sorted = 0;
  let min_sorted_index = 0;

  while(!sorted)
  {
    let index_less_so_far = min_sorted_index;
    for(let i = min_sorted_index; i < list.length; i++)
    {
      if(list[i + 1] < list[index_less_so_far])
      {
	index_less_so_far = i + 1;
      }
    }
    if(min_sorted_index != index_less_so_far)
    {
      let swap_helper = list[min_sorted_index];
      list[min_sorted_index] = list[index_less_so_far];
      list[index_less_so_far] = swap_helper;
    }        
    if((list.length - 1) - (min_sorted_index - 1) == 1)
    {
      if(list[min_sorted_index - 1] < list[list.length - 1])
	sorted = true;
    }
    min_sorted_index++;
  }
  return list;
}

console.log(selection_sort(arreglo));

function selection_sort_book(list)
{
  for(let i = 0; i < list.length - 1; i++)
  {
    let lowestNumberIndex = i;
    for(let j = i + 1; j < list.length; j++)
    {
      if(list[j] < list[lowestNumberIndex])
      {
	lowestNumberIndex = j;
      }
    }
    if(lowestNumberIndex != i)
    {
      let temp = list[i];
      list[i] = list[lowestNumberIndex];
      list[lowestNumberIndex] = temp;
    }
  }
  return list;
}

console.log(selection_sort_book(arreglo));