JSFiddle - React, Tailwind, and code Playground

JavaScript

var groups = {
  "group1": {
    "sum": 25,
    "count": 5
  },
  "group3": {
    "sum": 5,
    "count": 5
  }
}

for (var group in groups) {
  alert("[Loop access] " + group + " - sum: " + group["sum"] + " - count: " + group["count"]);
}

alert("[Direct access] group1 - sum: " + groups["group1"]["sum"] + " - count: " + groups["group1"]["count"]);

alert("[Direct access] group3 - sum: " + groups["group3"]["sum"] + " - count: " + groups["group3"]["count"]);