JSFiddle - React, Tailwind, and code Playground

JavaScript

function stringify(obj_from_json) {
  if (typeof obj_from_json !== "object" || Array.isArray(obj_from_json)) {
    // not an object, stringify using native function
    return JSON.stringify(obj_from_json);
  }
  // Implements recursive object serialization according to JSON spec
  // but without quotes around the keys.
  let props = Object.keys(obj_from_json)
    .map((key) => `${key}:${stringify(obj_from_json[key])}`)
    .join(",");
  return `{${props}}`;
}

var obj = {
  name: "John Smith",
  favoriteObjects: [
    { b: "there's", c: "always", d: "something" },
    [1, 2, "spam", { f: "hello" }],
    { vowels: "are missing" },
  ],
  job: {
    name: "Accountant",
    salary: 1000,
  },
  favoriteFruits: ["Apple", "Banana"],
};

document.body.innerHTML = `<pre>${stringify(obj)}</pre>`;