javascript change select options dynamically

1function getType() {
2  var x = document.getElementById("food").value;
3  var items;
4  if (x === "fruit") {
5    items = ["Apple", "Oranges", "Bananas"];
6  } else {
7    items = ["Eggplants", "Olives"]
8  }
9  var str = ""
10  for (var item of items) {
11    str += "<option>" + item + "</option>"
12  }
13  document.getElementById("pickone").innerHTML = str;
14}
15document.getElementById("btn").addEventListener("click", getType);