JSFiddle - React, Tailwind, and code Playground

HTML

<input id="lbl1" type="text" style="width:200px" /><br/>
<input id="lbl2" type="text" style="width:200px" />

JavaScript

var obj1 = {a: "a", b: "b"};
var obj2 = {c: "c", d: "d"};
var value = (JSON.stringify(obj1).concat(JSON.stringify(obj2))).replace("}{", ",");
document.getElementById("lbl1").setAttribute("value", value);
// back to object
var obj3 = JSON.parse(value);
document.getElementById("lbl2").setAttribute("value", obj3.a + " " + obj3.b + " " + obj3.c + " " + obj3.d);