JSFiddle - React, Tailwind, and code Playground

HTML

<p>My surname was once <span id="old"></span></p>
<p>And for now it is <span id="new"></span></p>

JavaScript

"use strict";

var Family = {
  name : ["Hooves"]
};

var Derpy = {
	name    : "Derpy",
  surname : Family.name
};

document.getElementById("old").textContent = Derpy.surname;

Family.name[0] = "Whooves";
// (!) //Family.name = ["Whooves"];

document.getElementById("new").textContent = Derpy.surname;