JSFiddle - React, Tailwind, and code Playground

JavaScript

function World() {
    this.mankind = new Mankind(this);
    getName = function(id) {
        return this.mankind.people[id].name;
    }
    alert('Здесь проживают: ' + this.mankind.city.map(getName));
}

function Mankind(world) {
    this.people = new Array();
    this.people[0] = new Man(this, 'Vasily');
    this.people[1] = new Man(this, 'Alessandra');
    this.city = [0, 1];
}

function Man(mankind, name) {
    this.name = name;
}

new World();