JSFiddle - React, Tailwind, and code Playground

JavaScript

function Vector(x, y) {
  if (x === undefined)
    x = 0;
  if (y === undefined)
    y = 0;
  this.x = x;
  this.y = y;
}
function Rectangle(x, y, w, h) {
  this.position = new Vector(x, y);
  this.width = w;
  this.height = h;
}

function GameObject() {
	this.bounds = new Rectangle();
}
Test.prototype = new GameObject();
Test.prototype.constructor = Test;
function Test() {
  this.bounds.width = 50;
  this.bounds.height = 50;
}

var objects = [];
for (var i = 0; i < 3; i++) {
	var test = new Test();
  test.bounds.position = new Vector(i, 0);
  alert(test.bounds.position.x);
  objects.push(test);
}
for (var j = 0; j < objects.length; j++)
	alert(objects[j].bounds.position.x);