Javascript sort stability

sort.js

function sortArray(n) {
  var array = [];
  for (var i = 1; i <= n; i++) {
    array.push({key: 10, name: i.toString()});
  }
  array.sort(function(a, b) {
    return a.key - b.key;
  });
  for(var j = 0; j < n; j++) {
    process.stdout.write(array[j].name + " ");
  }
}

for (var i = 5; i <= 15; i++) {
  sortArray(i);
  process.stdout.write(" (Array size: " + i + ")\n");
}


/* Output from running:

1 2 3 4 5  (Array size: 5)
1 2 3 4 5 6  (Array size: 6)
1 2 3 4 5 6 7  (Array size: 7)
1 2 3 4 5 6 7 8  (Array size: 8)
1 2 3 4 5 6 7 8 9  (Array size: 9)
1 2 3 4 5 6 7 8 9 10  (Array size: 10)
6 1 3 4 5 2 7 8 9 10 11  (Array size: 11)
7 1 3 4 5 6 2 8 9 10 11 12  (Array size: 12)
7 1 3 4 5 6 2 8 9 10 11 12 13  (Array size: 13)
8 1 3 4 5 6 7 2 9 10 11 12 13 14  (Array size: 14)
8 1 3 4 5 6 7 2 9 10 11 12 13 14 15  (Array size: 15)

*/