JSFiddle - React, Tailwind, and code Playground

JavaScript

var x = 5;

function PartyWithoutX(person) {
	// This property will go to window and pollute the global object
	dance = function (person) {
		document.write("Hello " + person.getFullName() + ", Welcome to the Party.");
	};

	this.showX = function () {
		// This will change the global x variable
		x = 25;
		document.write("Value of x is " + x);
	};
}

function Person(firstName, lastName) {
	this.firstName = firstName;
	this.lastName = lastName;
}

Person.prototype.getFullName = function () {
	return this.firstName + " " + this.lastName;
};

var dinesh = new Person("Dinesh", "Singh");

var p1 = new PartyWithoutX(dinesh);

document.write(window.dance(dinesh) + "; Enjoy!!");
document.write("<br/>");
document.write(p1.showX());
document.write("<br/>");
document.write(window.x);
document.write("<br/>");