Javascript - Using promise for post PHP, get undefined result

I'm a newbie in JS and have a little to no knowledge about asynchronous program and promise. I have a problem in getting result from post PHP as written in this code:

showModalLink = function(d, i) {
$('#myModalLabel').text(d.source.name + ' - ' + d.target.name);
$('#modalJum').text(d.jumlahlelangsama);
var lelang = d.daftarlelangsama.split(", ");
var lelangmodal = [];
var promises = [];
for (var i = 0; i < lelang.length; i++) {
   querystring = "select pemenang from lelang where id = " + lelang[i];
   console.log(querystring);
    var queryobj = {
        query: querystring
    };
    promises.push($.post('indikasi3modal.php', queryobj));   
}
Promise.all(promises).then(function(results) {
  if (results[i] == d.source.name) {
    console.log("1");
    lelangmodal.push(lelang[i] + " - dimenangkan oleh " + d.source.name);
    console.log(lelangmodal);
  }
  else if (results[i] == d.target.name) {
    console.log("2");
    lelangmodal.push(lelang[i] + " - dimenangkan oleh " + d.target.name);
    console.log(lelangmodal);
  }
  else {
    console.log("3");
    lelangmodal.push(lelang[i]);
    console.log(lelangmodal);
  }
  $('#modalLelang').text(lelangmodal);
  $('#myModal').modal('show');      
});}

I have no idea why the results[i] return undefined inside then function loop. Any help (or alternative ways to solve this) appreciated. Thanks!