how do I delay the exiting from a function in javaScript? [duplicate]

my problem is that I need to wait a bit before returning the value.
the function is returning the variable x before the var updates (or at least I think that it’s the problem).

var x; //now it's undefined
  con.connect(function(err) {
    if (err) throw err;
    con.query("SELECT * FROM usrs", function (err, result) {
      if (err) throw err;
      x= result; //trying to update x
  });
});
  return x; //returns undefined(because it doesn't have enough time to change so it stays like it was at the beginning)