I have json with name like:
product_1
product_2
product_3
Could I have loop with variable + number?
My problem is: json.subject__ + (i + 1)
const json = items[0].json["data"];
var count = json.count;
var subject = [];
for (i = 0; i < count; i++) {
  subject[i] = json.subject__ + (i + 1);
}
My json structure like this:
[
  {
    "data": {
      "use_for": "website",
      "product__1": "bai 1",
      "length__1: "option 1",
      "product__2": "bai 2",
      "length__2": "option 2",
      "product__3": "bai 3",
      "length__3": "option 3",
      "format__3": [
         "sss",
         "kkk", ...
 
    