JSFiddle - React, Tailwind, and code Playground

HTML

<div id="mygroup">
  <input type="text" name="sara">
  <input type="text" name="bella">
</div>

JavaScript

let obj = [];

let items = document.querySelectorAll("input");

items.forEach(function(item) {
  item.addEventListener('change', function() {
    let myname = this.name;
    let myvalue = this.value;
    let id = this.parentNode.id;
    obj[id] = [];
    obj[id][myname] = myvalue;
		console.log(obj);
  });
});